Medical Physiology

The hormone leptin, by binding to hypothalamic receptors, suppresses food intake and decreases body adiposity. Leptin receptors are also widely expressed in extra-hypothalamic areas such as hippocampus, amygdala and cerebellum, where leptin modulates synaptic transmission. Here we show that a defective leptin receptor affects the electrophysiological properties of cerebellar Purkinje neurons (PNs). PNs from (db/db) mice recorded in cerebellar slices display a higher firing rate of spontaneous action potentials than PNs from wild type (WT) mice. Blockade of GABAergic tonic inhibition with bicuculline in WT mice changes the firing pattern from continuous, uninterrupted spiking into bursting firing, but bicuculline does not produce these alterations in db/db neurons, suggesting that they receive a weaker GABAergic inhibitory input. Our results also show that the intrinsic firing properties (auto-rhythmicity) of WT and db/db PNs are different. Tonic firing of PNs, the only efferent drive from the cerebellar cortex, is a persistent signal to downstream cerebellar targets. The significance of leptin modulation of PNs spontaneous firing is not known. Also, it is not clear if the increased excitability of cerebellar PNs in db/db mice results from hyperglycemia or from the lack of leptin signaling, since both conditions coexist in the db/db strain.

Rises of intracellular Ca2+ ([Ca2+]i) are key signals for cell division, differentiation, and maturation. Similarly, they are likely to be important for the unique processes of meiosis and spermatogenesis, carried out exclusively by male germ cells. In addition, elevations of [Ca2+]i and intracellular pH (pHi) in mature sperm trigger at least two events obligatory for fertilization: capacitation and acrosome reaction. Evidence implicates the activity of Ca2+ channels modulated by pHi in the origin of these Ca2+ elevations, but their nature remains unexplored, in part because work in individual spermatozoa are hampered by formidable experimental difficulties. Recently, late spermatogenic cells have emerged as a model system for studying aspects relevant for sperm physiology, such as plasmalemmal ion fluxes. Here we describe the first study on the influence of controlled intracellular alkalinization on [Ca2+]i on identified spermatogenic cells from mouse adult testes. In BCECF [(2′,7′...

The role of ryanodine-sensitive intracellular Ca2+ stores present in nonmuscular cells is not yet completely understood. Here we examine the physiological parameters determining the dynamics of caffeine-induced Ca2+ release in individual fura-2–loaded sympathetic neurons. Two ryanodine-sensitive release components were distinguished: an early, transient release (TR) and a delayed, persistent release (PR). The TR component shows refractoriness, depends on the filling status of the store, and requires caffeine concentrations ≥10 mM. Furthermore, it is selectively suppressed by tetracaine and intracellular BAPTA, which interfere with Ca2+-mediated feedback loops, suggesting that it constitutes a Ca2+-induced Ca2+-release phenomenon. The dynamics of release is markedly affected when Sr2+ substitutes for Ca2+, indicating that Sr2+ release may operate with lower feedback gain than Ca2+ release. Our data indicate that when the initial release occurs at an adequately fast rate, Ca2+ trigger...

Ca2+ currents ( ICa) recorded from adrenal chromaffin cells (CCs) of spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats are similar to one another, but different from those recorded in other rodent species. ICa in WKY/SHR CCs comprises an early, transient ( ICae) and a late, sustained component ( ICas). In Wistar CCs, ICae is absent, and ICas is of greater amplitude. Activation and steady-state inactivation of ICae and ICas in WKY/SHR CCs suggest the recruitment of at least two populations of Ca2+ channels with different voltage dependence and kinetics. In WKY/SHR CCs, ICae is inhibited by nifedipine, enhanced by BAY K 8644, is not blocked by the mibefradil analog NNC 55–0396, and displays Ca2+-dependent inactivation and fast deactivation kinetics, suggesting that it results from the opening of L-type rather than T-type Ca2+ channels. ICae properties suggest that it originates from the opening of Ca2+ channels formed with the short splice variant (CaV1.342A). ...

Modulation of high-threshold voltage-dependent calcium channels by neurotransmitters has been the subject of numerous studies in cultures of neurons and chromaffin cells. However, no studies on such modulation exist in chromaffin cells in their natural environment, the intact adrenal medullary tissue. Here we performed such a study in voltage-clamped chromaffin cells of freshly prepared mouse adrenal slices under the whole cell configuration of the patch-clamp technique. The subcomponents of the whole cell inward Ca2+ current ( ICa) accounted for 49% for L-, 28% for N-, and 36% for P/Q-type channels. T-type Ca2+ channels or residual R-type Ca2+ currents were not seen. However, under the perforated-patch configuration, 20% of ICa accounted for a toxin-resistant R-type Ca2+ current. Exogenously applied ATP and methionine-enkephalin (Met-enk) inhibited ICa by 33%. Stop-flow and Ca2+ replacement by Ba2+, which favored the release of endogenous ATP and opioids, also inhibited ICa, with n...

Parkin is an ubiquitin‐E3 ligase that is involved in cellular mitophagy and was recently shown to contribute to controlling adipose tissue thermogenic plasticity. We found that Parkin expression is induced in brown (BAT) and white (WAT) adipose tissues of aged mice. We determined the potential role of Parkin in the aging-associated decline in the thermogenic capacity of adipose tissues by analyzing subcutaneous WAT, interscapular BAT, and systemic metabolic and physiological parameters in young (5 month-old) and aged (16 month-old) mice with targeted invalidation of the Parkin (Park2) gene, and their wild-type littermates. Our data indicate that suppression of Parkin prevented adipose accretion, increased energy expenditure and improved the systemic metabolic derangements, such as insulin resistance, seen in aged mice. This was associated with maintenance of browning and reduction of the age-associated induction of inflammation in subcutaneous WAT. BAT in aged mice was much less aff...

differences between menstrual cycle phases (p> 0.05). miR-30c-5p associated with testosterone concentration (R 2 =0.13, p=0.033). These pilot data indicate differences in adipose tissue miRNAs in healthy women across the menstrual cycle and a weak association with ovarian hormones. Further research in larger sample sizes is required to confirm regulation of miRNA expression across the menstrual cycle.

Cyclical changes in hormone profiles across the menstrual cycle are associated with alterations in metabolic control. MicroRNAs (miRNAs) contribute to regulating metabolic control, including adipose tissue metabolism. How fluctuations in hormonal profiles across the menstrual cycle affect adipose tissue miRNA expression remains unknown. Eleven healthy, regularly menstruating females underwent four sampling visits across their menstrual cycle. Subcutaneous abdominal adipose tissue and venous blood samples were collected at each sampling visit. Luteinizing hormone (LH) tests, calendar counting, and serum hormone concentrations were used to determine menstrual cycle phases: early-follicular (EF), late-follicular (LF), postovulatory (PO), and midluteal (ML). Serum follicle-stimulating hormone, LH, estrogen, progesterone, and testosterone were determined using multiplex magnetic bead panels and enzyme-linked immunosorbent assays. Global adipose tissue miRNA expression levels were determi...

IAEA AFRA TC in the last years is initiating in cooperation with its international partners and technical and expert’s staff from other IAEA departments the need of establishing the Master Program (MSc) and Postgraduate Diploma (PGD) in African Member States. This proposal aims to contribute to ongoing efforts by Member States in Africa to address the importance of Radiopharmacy in development of Good Radiopharmaceutical Practice in Nuclear Medicine and Departments and all institutions involved in the production, control, distribution and research of radiopharmaceuticals by promoting e-learning program in a combination of traditional teaching and practical work that provide effective, low cost educational opportunities to all professionals in a field of Radiopharmacy. The first component of the project will be to establish e-learning platform designed as an innovative learning apparatus that, working alongside conventional teaching methods, integrates education in all aspects of Rad...

AimAlzheimer's disease (AD) is largely considered a neuron‐derived insult, but also involves failure of astroglia. A recent study indicated that mutated presenilin 1 (PS1M146V), a putative endoplasmic reticulum (ER) Ca2+ channel with decreased Ca2+ conductance, impairs the traffic of astroglial peptidergic vesicles. Whether other pathogenically relevant PS1 mutants, such as PS1ΔE9, which code for ER channel with putative increased Ca2+ conductance, similarly affect vesicle traffic, is unknown.MethodsHere, we cotransfected rat astrocytes with plasmids encoding mutant PS1ΔE9 and atrial natriuretic peptide or vesicular glutamate transporter 1 tagged with fluorescent proteins (pANP.emd or pVGLUT1‐EGFP respectively), to microscopically examine whether alterations in vesicle mobility and Ca2+‐regulated release of gliosignalling molecules manifest as a general vesicle‐based defect; control cells were transfected to co‐express exogenous or native wild‐type PS1 and pANP.emd or pVGLUT1‐EG...

This 48-week, randomized, placebo-controlled phase 3 study (DMD114044; NCT01254019) evaluated efficacy and safety of subcutaneous drisapersen 6 mg/kg/week in 186 ambulant boys aged ≥5 years, with Duchenne muscular dystrophy (DMD) resulting from an exon 51 skipping amenable mutation. Drisapersen was generally well tolerated, with injection-site reactions and renal events as most commonly reported adverse events. A nonsignificant treatment difference (P = 0.415) in the change from baseline in six-minute walk distance (6MWD; primary efficacy endpoint) of 10.3 meters in favor of drisapersen was observed at week 48. Key secondary efficacy endpoints (North Star Ambulatory Assessment, 4-stair climb ascent velocity, and 10-meter walk/run velocity) gave consistent findings. Lack of statistical significance was thought to be largely due to greater data variability and subgroup heterogeneity. The increased standard deviation alone, due to less stringent inclusion/exclusion criteria, reduced th...

Myocardial fatty acid oxidation is regulated by carnitine palmitoyltransferase I (CPT I), which is inhibited by malonyl-CoA. Increased cardiac power causes a fall in malonyl-CoA content and accelerated fatty acid oxidation; however, the mechanism for the decrease in malonyl-CoA is unclear. Malonyl-CoA is formed by acetyl-CoA carboxylase (ACC) and degraded by malonyl-CoA decarboxylase (MCD); thus a fall in malonyl-CoA could be due to activation of MCD, inhibition of ACC, or both. This study assessed the effects of increased cardiac power on malonyl-CoA content and ACC and MCD activities. Anesthetized pigs were studied under control conditions and during increased cardiac power in response to dobutamine infusion and aortic constriction alone, under hyperglycemic conditions, or with the CPT I inhibitor oxfenicine. An increase in cardiac power was accompanied by increased myocardial O2 consumption, decreased malonyl-CoA concentration, and increased fatty acid oxidation. There were no di...

The fine structure of the secondary lamellae of gills was examined in two cold-water marine teleosts, the winter flounder, Pseudopleuronectes americanus, and the antarctic cod, Trematomus borchgrevinki. In both species the overall lamellar fine structure is similar to that of other marine teleosts. The major variations in cellular organization involve the distribution of both the "chloride cells" and the mucous cells on the secondary lamellae of P. americanus. At winter water temperatures of +2.5~ significantly more chloride and mucous cells are present than in summer with water temperatures of + 15.2 ~ C. Both cell types are routinely present throughout the length of a secondary lamella as far as the lamellar tip. The chloride cells on the secondary lamellae are always situated in the inner layer of epithelium deep to the outer pavement cells. T. borchgrevinki shows no apparent difference in the distribution of mucous cells either at its normal water temperature of-1.9 ~ C or at a temperature of + 4 ~ C, the upper limit of its thermal tolerance to which some specimens were adapted in the aquarium. Chloride cells were never observed on the secondary lamellae of T. borchgrevinki. This suggests that low environmental water temperatures may be related to the distribution of mucous cells and chloride cells on the secondary lamella of the teleost gill.

In recent years, the intestinal mucosa has proven to be an intriguing organ to study tissue oxygenation. The highly vascularized lamina propria juxtaposed to an anaerobic lumen containing trillions of metabolically active microbes results in one of the most austere tissue microenvironments in the body. Studies to date have determined that a healthy mucosa contains a steep oxygen gradient along the length of the intestine and from the lumen to the serosa. Advances in technology have allowed multiple independent measures and indicate that, in the healthy mucosa of the small and large intestine, the lumen-apposed epithelia experience Po2conditions of <10 mmHg, so-called physiologic hypoxia. This unique physiology results from a combination of factors, including countercurrent exchange blood flow, fluctuating oxygen demands, epithelial metabolism, and oxygen diffusion into the lumen. Such conditions result in the activation of a number of hypoxia-related signaling processes, includin...

73.33° ± 8.11°, significant differences were found in sagittal and coronal classifications. The most prevalent canal was: cylindrical sagittal shape (48.2 %); slanted-straight direction-course (57.6 %); Ya-type coronal shape (42.4 %); and one foramen incisive with two Stenson's foramina (1-2) (50.9 %). Sagittal shape was associated with sagittal direction-course (p < 0.001). Coronal shape was associated with axial classification (p < 0.001). Conclusions The NC anatomy is highly variable. Gender is related to the NC length and BBP width, while dental status is related to BBP length. There was an association between the different sagittal classifications of the NC and between the coronal shape and axial classification.

Anxiety is a risk factor for many adverse neuropsychiatric and socioeconomic outcomes, and has been linked to functional and structural changes in the ventromedial prefrontal cortex (VMPFC). However, the nature of these differences, as well as how they develop in children and adolescents, remains poorly understood. More effective interventions to minimize the negative consequences of anxiety require better understanding of its neurobiology in children. Recent research suggests that structural imaging studies may benefit from clearly delineating between cortical surface area and thickness when examining these associations, as these distinct cortical phenotypes are influenced by different cellular mechanisms and genetic factors. The present study examined relationships between cortical surface area and thickness of the VMPFC and a self-report measure of anxiety (SCARED-R) in 287 youths aged 7-20 years from the Pediatric Imaging, Neurocognition, and Genetics (PING) study. Age and gende...

ABSTRACTThe formation and refinement of synaptic connections are dependent on the activity that emerges from nascent synaptic connections. Such activity has the effect of regulating the production and release of specific neurotransmitters. To determine the role of activity in regulating the production of peptide‐positive synapses, we used antibodies against Phe‐Met‐Arg‐Phe‐NH2 and acetylated α‐tubulin as well as intracellular injections of Neurobiotin to examine varicosities belonging to heart excitor (HE) neurons on the heart tubes of medicinal leeches, Hirudo spp. We found that the production of peptide‐positive varicosities increased considerably during the last week of embryogenesis, which coincided with the emergence of rhythmic activity of the heart tube. When we compromised central input to HE neurons with bicuculline or by surgical ablation of the central pattern generator during early embryogenesis, we found that activity in the heart tubes and its rhythmicity were greatly ...

A case of a renal transplant recipient with colchicine-induced myopathy is presented. He was on colchicine therapy for 10 months. He was hospitalized for investigation of fatigue, severe myalgia in the lower extremities and elevated serum aminotransferase levels. His viral markers and other factors that may cause myalgia and that may increase the serum aminotransferase levels were either normal or negative. Creatine phosphokinase (CK) levels were normal. Electrophysiological findings indicated myopathy and muscle biopsy was consistent with vacuolar myopathy. After withdrawal of colchicine, the symptoms disappeared gradually and serum aminotransferase levels were normalized. We suggest that colchicine myopathy should be taken into account in patients who have been on colchicine therapy and had unexplained myalgia as well as elevated aminotransferase levels even with normal CK levels.

At present the progression of chronic renal failure is an intriguing matter [l]. One of the topics being debated is whether lowering the blood pressure (BP) reduces the progression of chronic renal failure: however, whether a lowered BP is the cause or the effect of a reduced progres sion is still a problem to be solved . Here we report an anecdotical case of a bad control of BP for 8 years with an unchanged or even ameliorated renal function. This fe male patient, aged 55, was discharged from our unit in January 1982, with a diagnosis of chronic pyelonephritis and two 9-cm kidneys, a 150/100 mm Hg BP and a creatinine of 180 umol. At the end of the year the BP was 220/120 mm Hg.

Analisamos as características clínicas e moleculares de 205 pacientes portadores das diferentes formas clínicas da deficiência da 21-hidroxilase, com diagnóstico hormonal e molecular definidos. As mutações mais freqüentes foram a I2 splice na forma perdedora de sal, a I172N na forma virilizante simples e a V281L na forma não clássica, com freqüências semelhantes às de outros estudos. Obtivemos baixa freqüência de deleção do gene da 21-hidroxilase, de forma semelhante ao identificado nas populações argentina e mexicana. Cinco mutações novas foram descritas em nossa população: G424S, H28+C, Ins 1003^1004 A, R408C e IVS2-2A&gt;G. A severidade do genótipo também se correlacionou diretamente com níveis mais elevados de 17OH-progesterona e de testosterona. As mutações foram classificadas em três grupos, de acordo com o comprometimento da atividade enzimática observado in vitro: Grupo A: atividade de 0-2%; Grupo B: atividade de 3-7% e Grupo C: atividade &gt;20%. Houve forte correlação do g...

According to a generally accepted concept, the stationary structure of the receptive field of a visually sensitive central neuron predetermines transformation and central processing of the incoming information, including that related to moving visual stimuli. We found, however, that a small group of visually sensitive neurons of the cat extrastriate cortical area 21a does not fit this statement and exhibits no responses to stationary visual stimuli while responding vigorously to moving images. The results of our experiments showed that response patterns of these neurons to moving stimuli display high degrees of diversification and processing of incoming visual information. We suppose that these neurons may be strictly specialized in the detection and central processing of visual information necessary for perception of moving images.

Background: Infant Respiratory Distress Syndrome (IRDS) is a major cause of neonatal morbidity and mortality, often linked to genetic mutations affecting pulmonary surfactant metabolism. Mutations in genes such as SFTPA1, SFTPA2, SFTPB, SFTPC, SFTPD, ABCA3, and NKX2-1 have been implicated in surfactant dysfunction and IRDS pathogenesis. However, the functional consequences of many nonsynonymous single nucleotide polymorphisms (nsSNPs) remain poorly characterized. Objective: This study aims to identify and prioritize potentially deleterious nsSNPs in surfactant-associated genes using an integrated computational approach, providing insights into their structural and functional impacts for future experimental validation. Methods: We performed a comprehensive in silico analysis of rare missense variants (MAF < 1%) obtained from public databases (dbSNP, ClinVar, UniProt). Functional impact was predicted using SIFT, PolyPhen-2, Panther, and CADD. Protein stability changes were assessed using I-Mutant2.0 and MUpro. Evolutionary conservation was evaluated via ConSurf, and structural modeling was carried out with AlphaFold, SWISS-MODEL, PyMOL, and GROMACS to analyze RMSD and hydrogen bonding patterns. Results: Mutation frequency analysis revealed ABCA3 as the most variant-rich gene (n = 36,391), while SFTPD had the lowest mutation load (n = 4,646). Consensus prediction identified several high-risk nsSNPs, including R276W (SFTPB), V48M (SFTPC), G86E (SFTPA2), and P131T (SFTPD), consistently classified as damaging across tools. Protein stability analysis confirmed significant destabilization for R276W (SFTPB) and V48M (SFTPC). Structural modeling showed increased RMSD and reduced hydrogen bonds in variants such as G123V (SFTPA1) and G100S (SFTPC), indicating potential structural disruption. Highly conserved residues (ConSurf score ≥ 7), especially those involving glycine or proline substitutions, were more likely to be functionally critical. Conclusion: This comprehensive in silico analysis identifies several high-confidence deleterious nsSNPs that may contribute to surfactant dysfunction and IRDS pathogenesis. These findings offer valuable insights for future functional studies and may aid in the development of targeted genetic screening strategies for IRDS risk assessment.

Patients with obstructive sleep apnea (OSA) are frequently obese and are predisposed to weight gain. They also have heightened sympathetic drive. We reasoned that noradrenergic activation of β3-receptors on adipocytes would inhibit leptin production, predisposing to obesity in sleep apnea. We therefore tested the hypothesis that obesity and predisposition to weight gain in OSA are associated with low levels of plasma leptin. We prospectively studied 32 male patients (43 ± 2 yr) with OSA who were newly diagnosed and never treated and who were free of any other diseases. Control measurements were obtained from 32 similarly obese closely matched male subjects (38 ± 2 yr). Leptin levels were 13.7 ± 1.3 and 9.2 ± 1.2 ng/ml in patients with OSA and controls, respectively ( P = 0.02). Weight gain over the year before diagnosis was 5.2 ± 1.7 and 0.5 ± 0.9 kg in sleep apnea patients and similarly obese control subjects, respectively ( P = 0.04). Muscle sympathetic activity was 46 ± 4 and 30 ...

) in mature starfish oocytes induces a massive calcium mobilization that results in the discharge of the cortical granules and in the elevation of the fertilization envelope. The Ca 2؉ liberation starts as a circumscribed subplasma membrane hotspot, which is followed by a flash of Ca 2؉ increase restricted to the cortical layer. Ca 2؉ propagates rapidly from these peripheral regions to the center of the oocyte, initiating calcium oscillations. Blockade of the inositol 1,4,5-trisphosphate receptors with heparin does not affect the liberation of Ca 2؉ at the initial hotspot or the cortical flash, but abolishes the centripetal spreading of the wave and the Ca 2؉ oscillations. In Ca 2؉ -free medium, LAT-A also initiates Ca 2؉ release at a discrete cortical point, but then propagates throughout the cell without first forming the uniform cortical flash. The latter is thus linked to the influx of external Ca 2؉ , somehow promoted by the depolymerization of cortical (microvillar) actin. The Ca 2؉ response to spermatozoa (i.e., peripheral hotspot, cortical flash, globalization of the signal) closely mimics that promoted by LAT-A. Thus, the initial cortical release of Ca 2؉ promoted by the sperm may be due to the depolymerization of actin.-Lim, D.,

Nicotinic acid adenine dinucleotide phosphate (NAADP) is involved in the Ca 2+ response observed at fertilization in several species, including starfish. In this study, we have employed Ca 2+ imaging and the single-electrode voltage-clamp technique to investigate whether the NAADP-mediated Ca 2+ entry discovered in our laboratory in starfish oocytes was underlain by a membrane current and whether the response to NAADP required an intact cytoskeleton. Uncaging of preinjected NAADP evoked a cortical Ca 2+ flash that was followed by the spreading of the wave to the remainder of the cell. No Ca 2+ increase was detected in Ca 2+ -free sea water. Under voltage-clamp conditions, the photoliberation of NAADP activated an inward rectifying membrane current, which reversed at potentials more positive than +50 mV and was abolished by removal of Ca 2+ but not of Na + . The current was affected by preincubation with verapamil, SK&F 96356, and thapsigargin but not by preinjection of heparin, 8-NH 2 -cyclic ADP-ribose, or both antagonists. The membrane current and the Ca 2+ wave were inhibited by latrunculin-A and jasplakinolide, which depolymerize and stabilize actin cytoskeleton, respectively. These data offer the first demonstration that NAADP initiates a Ca 2+ sweep by activating a Ca 2+ -permeable membrane current that requires an intact F-actin cytoskeleton as other Ca 2+ -permeable currents, such as I CRAC and I ARC .

Cyclic ADP-ribose (cADPr) is a second messenger that regulates intracellular free [Ca 2+ ] ([Ca 2+ ] i ) in a variety of cell types, including immature oocytes from the starfish Astropecten auranciacus. In this study, we employed confocal laser scanning microscopy and voltage clamp techniques to investigate the source of the cADPr-elicited Ca 2+ wave originating from the cortical Ca 2+ patches we have described previously. The Ca 2+ swing was accompanied by a membrane current with a reversal potential of %+20 mV. Decreasing external Na + almost abolished the current without affecting the Ca 2+ response. Removal of extracellular Ca 2+ altered neither the Ca 2+ transient nor the ionic current, nor did the holding potential exert any effect on the Ca 2+ wave. Both the Ca 2+ response and the membrane current were abolished when BAPTA, ruthenium red or 8-NH 2 -cADPr were preinjected into the oocytes, while perfusion with ADPr did not elicit any [Ca 2+ ] i increase or ionic current. However, elevating [Ca 2+ ] i by uncaging Ca 2+ from nitrophenyl-(NP-EGTA) or by photoliberating inositol 1,4,5-trisphosphate (InsP 3 ) induced an ionic current with biophysical properties similar to that elicited by cADPr. These results suggest that cADPr activates a Ca 2+ wave by releasing Ca 2+ from intracellular ryanodine receptors and that the rise in [Ca 2+ ] i triggers a non-selective monovalent cation current that does not seem to contribute to the global Ca 2+ elevation.

In invertebrates oocytes or eggs, the fertilization or activation potential establishes the fast electrical block to polyspermy and, in some species, provides the Ca 2+ influx which contributes to the following intracellular Ca 2+ wave. In echinoderms, the molecule triggering the activation potential is still unknown. The aim of this study was to assess whether nicotinic acid-adenine dinucleotide phosphate (NAADP) elicited the fertilization potential in starfish oocytes. The changes in membrane potential induced by the sperm were measured in oocytes held at a low resting potential, so that the Ca 2+ -action potential was inactivated and only the initial slower depolarization caused by the sperm could be studied. Decreasing extracellular Na + concentration did not prevent the onset of the fertilization potential, while removal of external Ca 2+ abolished it. The pre-incubation with SK&F 96365 and verapamil and the pre-injection of BAPTA inhibited the fertilization potential, while the injection of heparin only reduced its duration. The biophysical and pharmacological properties of the sperm-elicited depolarization were similar to those displayed by the NAADP-activated Ca 2+ -mediated current recently described in starfish oocytes. Indeed, the desensitization of NAADP-receptors prevented the onset of the fertilization potential. Taken together, these data suggest that NAADP could trigger the fertilization potential in starfish oocytes.

Starfish oocytes undergo massive intracellular Ca2+ signalling during meiotic maturation and fertilization. Although the igniting stimulus of Ca2+ mobilization may differ in different cell contexts, its final leverage is usually the Ca2+‐releasing second messengers such as InsP3, cADPr and NAADP. The general scheme of intracellular Ca2+ release is that the corresponding receptors for these molecules serve as ion channels to release free Ca2+ from its internal stores such as the lumen of the endoplasmic reticulum. However, a growing body of evidence has suggested that intracellular Ca2+ release can be strongly modulated by the actin cytoskeleton. Although it is known that Ca2+ contributes to remodelling of the actin cytoskeleton, whether the actin cytoskeleton modulates Ca2+ signalling in return has not been much explored. An emerging candidate to answer to this reciprocal causality of Ca2+ and the actin cytoskeleton may be actin‐binding proteins. In this review, we discuss how the a...

Background: Induction of haemeoxygenase-1 (HO-1) increases adiponectin secretion by remodeling adipose tissue in obesity. The objective of our study is to explore whether HO-1 induction directly improves endothelial function independent of adiponectin changes in obese rats. Methods: Rats were divided into control and obesity groups. Aortic endothelial function was determined by measuring endothelium-dependent vasodilatation (EDV). Vascular segments of the obese rats were incubated in an organ bath in the presence or absence of cobalt protoporphyrin (CoPP) or CoPP plus stannous protoporphyrin. Nitric oxide (NO) production, superoxide anion production and NF-κB p65 expression in the aorta were determined. The expression of AMP-activated kinase (AMPK), Akt and endothelial nitric oxide synthase (eNOS) in endothelial cells was determined by western blotting. The aortic rings from the obese rats were then incubated with CoPP in the presence of specific inhibitors of AMPK, phosphatidylinositol 3-kinase (PI3K) or eNOS. Results: Acetylcholine-induced EDV was significantly attenuated in the obese rats, compared with the NC group (p < 0.05). Preincubation of vessels from obese rats with CoPP significantly increased EDV (p < 0.05). However, this beneficial effect of CoPP was partly attenuated in vitro in the presence of inhibitors of AMPK, PI3K or eNOS. HO-1 induction with CoPP significantly increased the activation of the AMPK-PI3K/Akt-eNOS pathway and NO production in parallel with reduced superoxide anion production and NF-κB p65 expression in obese rats. Conclusions: HO-1 induction with CoPP directly improved endothelial function in obese rats independent of adiponectin changes. The mechanism of this protective effect is related to increasing NO production by activation of the AMPK-PI3K/Akt-eNOS signaling pathway.

Background: The induction of haemeoxygenase-1 (HO-1) exerts beneficial effects in the setting of endothelial dysfunction in obesity. High free fatty acid (FFA) levels are a common feature of obesity and are the primary cause of endothelial dysfunction. The objective of our study was to explore the effects of HO-1 induction on FFA-induced endothelial dysfunction in rats. Methods: Rats received FFA treatment with either cobalt protoporphyrin (CoPP) to induce HO-1 or stannous protoporphyrin (SnPP) to inhibit HO-1. Endothelial function was determined by measuring endothelium-dependent vasodilatation (EDV). Nitric oxide (NO) production, superoxide production and nuclear factor (NF)-κB expression in the aorta were each determined. The levels of adenosine monophosphate (AMP)-activated kinase (AMPK) and endothelial nitric oxide synthase (eNOS) expression in endothelial cells were determined via Western blotting. Results: Induction of HO-1 by CoPP decreased circulating FFA, highsensitivity C-reactive protein and malondialdehyde levels and increased serum adiponectin and glutathione levels compared with the FFA group (P<0.05). High FFA levels resulted in EDV impairment, which was improved by HO-1 induction (P<0.05). Induction of HO-1 increased NO levels and reduced aortic superoxide production and NF-κB expression compared with the FFA group. The FFA group exhibited decreased AMPK expression and eNOS phosphorylation, both of which were enhanced via HO-1 induction (P<0.05). The beneficial effects of CoPP on EDV were partially attenuated in vitro in the presence of inhibitors of AMPK, phosphatidylinositol 3-kinase (PI3K), and eNOS. Conclusions: HO-1 induction with CoPP improves FFA-induced endothelial dysfunction in the rat aorta. The protective mechanism appears to be related to the activation of the AMPK-PI3K-eNOS pathway as a result of increased adiponectin levels as well as decreased inflammation and oxidative stress.

Aims: To determine whether irisin could improve endothelial dysfunction by regulating heme oxygenase-1(HO-1)/adiponectin axis in perivascular adipose tissue (PVAT) in obesity. Methods: Male C57BL/6 mice were fed with a high-fat diet (HFD) with or without irisin treatment. Endothelium-dependent vasorelaxation of the thoracic aorta with or without PVAT (PVAT+ or PVAT-) was determined. Western blot was employed to determine the levels of HO-1 and adiponectin in PVAT. UCP-1, Cidea, and TNF-α gene expression in PVAT were tested by real-time PCR. Results: The presence of PVAT significantly impaired endothelial function in the HFD mice. Treatment of HFD mice with irisin significantly restored this impairment and improved endothelial function in vivo or ex vivo. Incubated aortic rings (PVAT-) with PVATderived conditioned medium (CM) from HFD mice impaired endothelial function in control mice. This impairment was prevented by incubating the aortic rings (PVAT-) from HFD mice with PVAT-derived CM from irisin. However, the beneficial effects were partly attenuated in the presence of HO-1 inhibitor and adiponectin receptor blocking peptide. Treatment of HFD mice with irisin significantly increased NO production, protein levels of HO-1 and adiponectin, mRNA expressions of UCP-1 and Cidea, and decreased superoxide production and TNF-α expression in PVAT. Conclusion: Irisin improved endothelial function by modulating HO-1/ adiponectin axis in PVAT in HFD-induced obese mice. These findings suggest that regulating PVAT function may be a potential mechanism by which irisin improves endothelial function in obesity.

Irisin is a novel hormone secreted by myocytes. Lower levels of irisin are independently associated with endothelial dysfunction in obese subjects. The objective of this study was to explore whether irisin exerts a direct vascular protective effect on endothelial function in high-fat-diet-induced obese mice. Male C57BL/6 mice were given chow or a high-fat diet with or without treatment with irisin. Aortic endothelial function was determined by measuring endothelium-dependent vasodilatation (EDV). Nitric oxide (NO) in the aorta was determined. The effect of irisin on the levels of AMP-activated protein kinase (AMPK), Akt, and endothelial NO synthase (eNOS) phosphorylation in endothelial cells was determined. Human umbilical vein endothelial cells were used to study the role of irisin in the AMPK-eNOS pathway. Acetylcholine-stimulated EDV was significantly lower in obese mice compared with control mice. Treatment of obese mice with irisin significantly enhanced EDV and improved endothelial function. This beneficial effect of irisin was partly attenuated in the presence of inhibitors of AMPK, Akt, and eNOS. Treatment of obese mice with irisin enhanced NO production and phosphorylation of AMPK, Akt, and eNOS in endothelial cells. These factors were also enhanced by irisin in human umbilical vein endothelial cells in vitro. Suppression of AMPK expression by small interfering RNA blocked irisin-induced eNOS and Akt phosphorylation and NO production. We have provided the first evidence that irisin improves endothelial function in aortas of high-fat-diet-induced obese mice. The mechanism for this protective effect is related to the activation of the AMPK-eNOS signaling pathway. irisin; endothelial function; nitric oxide; obesity Irisin improved endothelial function in aortas of high-fat-dietinduced obese mice. The mechanism for the protective effect of irisin is related to activation of the AMP-activated protein kinase-endothelial nitric oxide synthase signaling pathway.

Induction of haemeoxygenase-1 (HO-1) increases adiponectin secretion by remodeling adipose tissue in obesity. The objective of our study is to explore whether HO-1 induction directly improves endothelial function independent of adiponectin changes in obese rats. Rats were divided into control and obesity groups. Aortic endothelial function was determined by measuring endothelium-dependent vasodilatation (EDV). Vascular segments of the obese rats were incubated in an organ bath in the presence or absence of cobalt protoporphyrin (CoPP) or CoPP plus stannous protoporphyrin. Nitric oxide (NO) production, superoxide anion production and NF-κB p65 expression in the aorta were determined. The expression of AMP-activated kinase (AMPK), Akt and endothelial nitric oxide synthase (eNOS) in endothelial cells was determined by western blotting. The aortic rings from the obese rats were then incubated with CoPP in the presence of specific inhibitors of AMPK, phosphatidylinositol 3-kinase (PI3K) ...

The recognition of discernible anatomical regularities that appear to self-organize during development makes apparent the modular organization of the cerebral cortex. The metabolic cost engendered in sustaining interneuronal communications has emphasized the viability of short connections among neighboring neurons. This pattern of connectivity establishes a microcircuit which is repeated in parallel throughout the cerebral cortex. This canonical circuit is contained within the smallest module of information processing of the cerebral cortex; one which Vernon Mountcastle called the minicolumn. Plasticity within the brain is accounted, in part, by the presence of weak linkages that allow minicolumns to process information from a variety of sources and to quickly adapt to environmental exigencies without a need for genetic change. Recent research suggests that interlaminar correlated firing between minicolumns during the decision phase of target selection provides for the emergence of some executive functions. Bottlenecks of information processing within this modular minicolumnar organization may account for a variety of mental disorders observed in neurodevelopmental conditions.

The recognition of discernible anatomical regularities that appear to self-organize during development makes apparent the modular organization of the cerebral cortex. The metabolic cost engendered in sustaining interneuronal communications has emphasized the viability of short connections among neighboring neurons. This pattern of connectivity establishes a microcircuit which is repeated in parallel throughout the cerebral cortex. This canonical circuit is contained within the smallest module of information processing of the cerebral cortex; one which Vernon Mountcastle called the minicolumn. Plasticity within the brain is accounted, in part, by the presence of weak linkages that allow minicolumns to process information from a variety of sources and to quickly adapt to environmental exigencies without a need for genetic change. Recent research suggests that interlaminar correlated firing between minicolumns during the decision phase of target selection provides for the emergence of ...

There is no accepted pathology to autism spectrum disorders (ASD) but research suggests the presence of an altered excitatory/inhibitory (E/I) bias in the cerebral cortex. Repetitive transcranial magnetic stimulation (rTMS) offers a non-invasive means of modulating the E/I cortical bias with little in terms of side effects. In this study, 124 high functioning ASD children (IQ &gt; 80, &lt;18 years of age) were recruited and assigned using randomization to either a waitlist group or one of three different number of weekly rTMS sessions (i.e., 6, 12, and 18). TMS consisted of trains of 1.0 Hz frequency pulses applied over the dorsolateral prefrontal cortex (DLPFC). The experimental task was a visual oddball with illusory Kanizsa figures. Behavioral response variables included reaction time and error rate along with such neurophysiological indices such as stimulus and response-locked event-related potentials (ERP). One hundred and twelve patients completed the assigned number of TMS se...

Objectives: Reports in autism spectrum disorders (ASD) of a minicolumnopathy with consequent deficits of lateral inhibition help explain observed behavioral and executive dysfunctions. We propose that neuromodulation based on low frequency repetitive Transcranial Magnetic Stimulation (rTMS) will enhance lateral inhibition through activation of inhibitory double bouquet interneurons and will be accompanied by improvements in the prefrontal executive functions. In addition we proposed that rTMS will improve cortical excitation/inhibition ratio and result in changes manifested in event-related potential (ERP) recorded during cognitive tests. Along with traditional clinical behavioral evaluations the current study used ERPs in a visual oddball task with illusory figures. We compared clinical, behavioral and electrocortical outcomes in two groups of children with autism (TMS, waitlist group). We predicted that 18 session long course in autistic patients will have better behavioral and ERP outcomes as compared to age-and IQ-matched WTL group. We used 18 sessions of 1 Hz rTMS applied over the dorso-lateral prefrontal cortex in 27 individuals with ASD diagnosis. The WTL group was comprised of 27 age-matched subjects with ASD tested twice. Both TMS and WTL groups were assessed at the baseline and after completion of 18 weekly sessions of rTMS (or wait period) using clinical behavioral questionnaires and during performance on visual oddball task with Kanizsa illusory figures. Results: Post-TMS evaluations showed decreased irritability and hyperactivity on the Aberrant Behavior Checklist (ABC), and decreased stereotypic behaviors on the Repetitive Behavior Scale (RBS-R). Following rTMS course we found decreased amplitude and prolonged latency in the frontal and fronto-central N100, N200 and P300 (P3a) ERPs to non-targets in active TMS treatment group. TMS resulted in increase of P2d (P2a to targets minus P2a to non-targets) amplitude. These ERP changes along with increased centro-parietal P100 and P300 (P3b) to targets are indicative of more efficient processing of information post-TMS treatment. Another important finding was decrease of the latency and increase of negativity of error-related negativity (ERN) during commission errors that may reflect improvement in error monitoring and correction function. Enhanced information processing was also manifested in lower error rate. In addition we calculated normative post-error treaction time (RT) slowing response in both groups and found that rTMS treatment was accompanied by post-error RT slowing and higher accuracy of responses, whereas the WTL group kept on showing typical for ASD post-error RT speeding and higher commission and omission error rates. Results from our study indicate that rTMS improves executive functioning in ASD as evidenced by normalization of ERP responses and behavioral reactions (RT, accuracy) during executive function test, and also by improvements in clinical evaluations.

Background: The aim of the study is to compare the effects of hyperhomocysteinemia induced by methionine overload on lipid parameters and structure of the aorta in both male and female rabbits. Materials and methods: Study is carried on 20 male rabbits (control, n=11 and experimented, n=9) and 16 female rabbits, control (n=8) and tested (n=8). Control models are fed standard diet, the Met females and males received standard diet supplemented with Met (500 mg/day) during 3 months. Results obtained from MetM and MetF are compared with those of the respective controls. The body weight is measured, the parameters, Hcy, total cholesterol, total lipids, TG, atherogenicity index ((VLDL+LDL)/ HDL) are determinate by appropriate methods (FPIA, colorimetry). In aorta tissue we assess the total lipids, TC and TG contents and realize a histological study (Masson&#39;s staining). Results and discussion: the Met-enriched diet causes a low increase of Hcy (p&lt;0.05) in male, but a significant inc...

Modeling the electric field and images in electric fish contributes to a better understanding of the pre-receptor conditioning of electric images. Although the boundary element method has been very successful for calculating images and fields, complex electric organ discharges pose a challenge for active electroreception modeling. We have previously developed a direct method for calculating electric images which takes into account the structure and physiology of the electric organ as well as the geometry and resistivity of fish tissues. The present article reports a general application of our simulator for studying electric images in electric fish with heterogeneous, extended electric organs. We studied three species of Gymnotiformes, including both wave-type (Apteronotus albifrons) and pulse-type (Gymnotus obscurus and Gymnotus coropinae) fish, with electric organs of different complexity. The results are compared with the African (Gnathonemus petersii) and American (Gymnotus omaro...

Defects in vesicular trafficking underlie a wide variety of human diseases. Genetic disruption of leucine-rich repeat kinase 2 (LRRK2) in rodents results in epithelial vesicular trafficking errors that can also be induced by treatment of animals with LRRK2 kinase inhibitors. Here we demonstrate that defects in human renal cells lacking LRRK2 phenocopy those seen in the kidneys of Lrrk2 knockout mice, characterized by accumulation of intracellular waste vesicles and fragmentation of the Golgi apparatus. This phenotype can be recapitulated by knockdown of N-ethylmaleimide-sensitive factor, which physically associates with LRRK2 in renal cells. Deficiency in either protein leads to a defect in trans-Golgi to lysosome protein trafficking, which compromises the capacity of lysosomes to degrade endocytic and autophagic cargo. In contrast, neither bulk endocytosis nor autophagic flux are impaired when LRRK2 is acutely knocked down in normal immortalized human kidney (HK2) cells. These data...

Background. Ivabradine is an If ion current inhibitor that has proved to reduce mortality in patients with systolic heart failure by slowing heart rate without decreasing myocardial contractility. Photoplethysmography is a simple, low-cost optical technique that can evaluate vascular function and detect changes in blood flow, pulse, and swelling of tissular microvascular space. Objective. To evaluate the effect of ivabradine on endothelial function by photoplethysmography in diastolic and right heart failure patients. Methodology. 15 patients were included (mean age of 78.1 ± 9.2 years) with optimally treated diastolic and right heart failure. They underwent photoplethysmography before and after induced ischemia to evaluate the wave blood flow on the finger, using the maximum amplitude time/total time (MAT/TT) index. Two measurements were made before and after oral Ivabradine (mean 12.5 mg a day during 6 months of followup). Results. In the study group, the MAT/TT index was 29.1 ± 2...

Annexin A2 (ANXA2) is present in vivo in the mid-and late-secretory endometria and is mainly localized in the luminal epithelium. Our aim was to evaluate its function in regulating the human implantation process. With an in vitro adhesion model, constructed to evaluate how the mouse embryo and JEG-3 spheroids attach to human endometrial epithelial cells, we demonstrated that ANXA2 inhibition significantly diminishes embryo adhesiveness. ANXA2 is also implicated in endometrial epithelial cell migration and trophoblast outgrowth. ANXA2 was seen to be linked to the RhoA/ROCK pathway and to regulate cell adhesion. We noted that ANXA2 inhibition significantly reduces active RhoA, although RhoA inactivation does not alter the ANXA2 levels. RhoA inactivation and ROCK inhibition also moderate embryo adhesiveness to endometrial epithelial cells. We corroborated that the induction of constitutively active RhoA partially reverses the effects of ANXA2 inhibition on endometrial adhesiveness. These molecules colocalize on the plasma membrane of endometrial epithelial cells, and a large proportion of ANXA2 and RhoA are colocalized in the F-actin networks. The functional effects of ANXA2 inhibition and RhoA/ROCK inactivation are associated with significant alterations in F-actin organization and its depolymerization. ANXA2 may act upstream of the RhoA/ROCK pathway by regulating F-actin remodeling and is a key factor in human endometrial adhesiveness.

The kinetics of amiloride action on the isolated epithelium of the hen coprodaeum are reported. Tissues were taken from birds fed on low salt diets for 9-10 days, conditions which induce a high resting short circuit current due to sodium and sensitive to amiloride. The relation between the inhibition of amiloride sensitive short circuit current and blocker concentration obeyed simple mass laws with an apparent stoichiometry of 1 : 1 between amiloride and the sodium entry sites. The concentration of amiloride producing its half maximal effect (K~) was 1.77 _+ 0.20 laM at a sodium concentration of 130 raM. There was a shallow dependence of K~ on sodium concentration, the value of K~ falling to 0.78 _+ 0.1 gM at 1.3 mM Na. The relation of Ki to Na concentration was linear indicating competitive antagonism. The sodium concentration which half saturates the amiloride site (KN,) was 80 raM. This value is very different from the concentration of sodium which half saturates SCC (Kscc = 5-7 raM) suggesting there are at least two sites at which sodium can modify the transporting charadteristics. These data are compared to those for other epithelia where Kscc and Kya are rather similar. The benzyl derivative of amiloride (benzamil) was found to be 11.6 times more potent than amiloride on this tissue. The potency ratio is similar to that for other sodium transporting epithelia suggesting that the structure of the ion translocation mechanism is partly conserved between species although the Ki for amiloride may vary by an order of magnitude.

An in vivo rat model was used to evaluate the effects of Escherichia coli pneumonia on lung function and surfactant in bronchoalveolar lavage (BAL). Total extracellular surfactant was increased in infected rats compared with controls. BAL phospholipid content in infected rats correlated with the severity of alveolar-capillary leak as reflected in lavage protein levels (R(2) = 0.908, P &lt; 0.0001). Western blotting showed that levels of surfactant protein (SP)-A and SP-D in BAL were significantly increased in both large and small aggregate fractions at 2 and 6 h postinstillation of E. coli. SP-B was also increased at these times in the large aggregate fraction of BAL, whereas SP-C levels were increased at 2 h and decreased at 6 h relative to controls. The small-to-large (S/L) aggregate ratio (a marker inversely proportional to surfactant function) was increased in infected rats with &gt;50 mg total BAL protein. There was a significant correlation (R(2) = 0.885, P &lt; 0.0001) betwee...