The properties of voltage dependent Ca2+ current (VDCC) were investigated in interstitial cells of Cajal (ICC) distributed in the myenteric layer (ICC-MY) of guinea-pig antrum. In tissue, ICC-MY showed c-Kit positive reactions and produced driving potentials with the amplitude and frequency of about 62 mV and 2 times min(-1), respectively, in the presence of 1micrometer nifedipine. Single ICC-MY isolated by enzyme treatment also showed c-Kit immunohistochemical reactivity. These cells were also identified by generation of spontaneous inward current under K+-rich pipette solution. The voltage clamp experiments revealed the amplitude of - 329 pA inward current at irregular frequency. With Cs+-rich pipette solution at Vh=?80 mV, ICC-MY produced voltage-dependent inward currents (VDIC), and nifedipine (1micrometer) blocked VDIC. Therefore, we successfully isolated c-Kit positive single ICC from guinea-pig stomach, and found that ICC-MY potently produced dihydropiridine sensitive L-type voltage-dependent Ca2+ currents (VDCCL).
Interstitial Cells of Cajal ; Nifedipine ; Stomach

Eugenol is widely used in dentistry to relieve pain. We have recently demonstrated voltage-gated Na+ and Ca2+ channels as molecular targets for its analgesic effects, and hypothesized that eugenol acts on P2X3, another pain receptor expressed in trigeminal ganglion (TG), and tested the effects of eugenol by whole-cell patch clamp and Ca2+ imaging techniques. In the present study, we investigated whether eugenol would modulate 5'-triphosphate (ATP)-induced currents in rat TG neurons and P2X3-expressing human embryonic kidney (HEK) 293 cells. ATP-induced currents in TG neurons exhibited electrophysiological properties similar to those in HEK293 cells, and both ATP- and alpha,beta-meATP-induced currents in TG neurons were effectively blocked by TNP-ATP, suggesting that P2X3 mediates the majority of ATP-induced currents in TG neurons. Eugenol inhibited ATP-induced currents in both capsaicin-sensitive and capsaicin-insensitive TG neurons with similar extent, and most ATP-responsive neurons were IB4-positive. Eugenol inhibited not only Ca2+ transients evoked by alpha,beta-meATP, the selective P2X3 agonist, in capsaicin-insensitive TG neurons, but also ATP-induced currents in P2X3-expressing HEK293 cells without co-expression of transient receptor potential vanilloid 1 (TRPV1). We suggest, therefore, that eugenol inhibits P2X3 currents in a TRPV1-independent manner, which contributes to its analgesic effect.
Adenosine Triphosphate ; Animals ; Dentistry ; Eugenol ; HEK293 Cells ; Humans ; Kidney ; Neurons ; Nociceptors ; Rats ; Trigeminal Ganglion

Retinal prostheses are being developed to restore vision for the blind with retinal diseases such as retinitis pigmentosa (RP) or age-related macular degeneration (AMD). Among the many issues for prosthesis development, stimulation encoding strategy is one of the most essential electrophysiological issues. The more we understand the retinal circuitry how it encodes and processes visual information, the greater it could help decide stimulation encoding strategy for retinal prosthesis. Therefore, we examined how retinal ganglion cells (RGCs) in in-vitro retinal preparation act together to encode a visual scene with multielectrode array (MEA). Simultaneous recording of many RGCs with MEA showed that nearby neurons often fired synchronously, with spike delays mostly within 1 ms range. This synchronized firing - narrow correlation - was blocked by gap junction blocker, heptanol, but not by glutamatergic synapse blocker, kynurenic acid. By tracking down all the RGC pairs which showed narrow correlation, we could harvest 40 functional connectivity maps of RGCs which showed the cell cluster firing together. We suggest that finding functional connectivity map would be useful in stimulation encoding strategy for the retinal prosthesis since stimulating the cluster of RGCs would be more efficient than separately stimulating each individual RGC.
Fires ; Gap Junctions ; Heptanol ; Kynurenic Acid ; Macular Degeneration ; Neurons ; Prostheses and Implants ; Retinal Diseases ; Retinal Ganglion Cells ; Retinaldehyde ; Retinitis Pigmentosa ; Synapses ; Track and Field ; Vision, Ocular ; Visual Prosthesis

The advantages of monounsaturated fatty acids (MUFAs) on insulin resistance and type 2 diabetes mellitus (T2DM) have been well established. However, the molecular mechanisms of the anti-diabetic action of MUFAs remain unclear. This study examined the anti-hyperglycemic effect and explored the molecular mechanisms involved in the actions of fish oil- rich in MUFAs that had been acquired from hybrid catfish (Pangasius larnaudii×Pangasianodon hypophthalmus) among experimental type 2 diabetic rats. Diabetic rats that were fed with fish oil (500 and 1,000 mg/kg BW) for 12 weeks significantly reduced the fasting plasma glucose levels without increasing the plasma insulin levels. The diminishing levels of plasma lipids and the muscle triglyceride accumulation as well as the plasma leptin levels were identified in T2DM rats, which had been administrated with fish oil. Notably, the plasma adiponectin levels increased among these rats. The fish oil supplementation also improved glucose tolerance, insulin sensitivity and pancreatic histological changes. Moreover, the supplementation of fish oil improved insulin signaling (p-Akt(Ser473) and p-PKC-ζ/λ(Thr410/403)), p-AMPK(Thr172) and membrane GLUT4 protein expressions, whereas the protein expressions of pro-inflammatory cytokines (TNF-α and nuclear NF-κB) as well as p-PKC-θ(Thr538) were down regulated in the skeletal muscle. These data indicate that the effects of fish oil-rich in MUFAs in these T2DM rats were partly due to the attenuation of insulin resistance and an improvement in the adipokine imbalance. The mechanisms of the anti-hyperglycemic effect are involved in the improvement of insulin signaling, AMPK activation, GLUT4 translocation and suppression of pro-inflammatory cytokine protein expressions.
Adipokines ; Adiponectin ; AMP-Activated Protein Kinases ; Animals ; Blood Glucose ; Catfishes ; Cytokines ; Diabetes Mellitus, Type 2 ; Fasting ; Fatty Acids, Monounsaturated ; Fish Oils ; Glucose ; Glucose Transporter Type 4 ; Insulin ; Insulin Resistance ; Leptin ; Membranes ; Muscle, Skeletal ; Plasma ; Rats* ; Triglycerides

Caspases, a family of cysteine proteases, cleave substrates and play significant roles in apoptosis, autophagy, and development. Recently, our group identified 72 genes that interact with Death Caspase-1 (DCP-1) proteins in Drosophila by genetic screening of 15,000 EP lines. However, the cellular functions and molecular mechanisms of the screened genes, such as their involvement in apoptosis and autophagy, are poorly understood in mammalian cells. In order to study the functional characterizations of the genes in human cells, we investigated 16 full-length human genes in mammalian expression vectors and tested their effects on apoptosis and autophagy in human cell lines. Our studies revealed that ALFY, BIRC4, and TAK1 induced autophagy, while SEC61A2, N-PAC, BIRC4, WIPI1, and FALZ increased apoptotic cell death. BIRC4 was involved in both autophagy and apoptosis. Western blot analysis and luciferase reporter activity indicated that ALFY, BIRC4, PDGFA, and TAK1 act in a p53-dependent manner, whereas CPSF1, SEC61A2, N-PAC, and WIPI1 appear to be p53-independent. Overexpression of BIRC4 and TAK1 caused upregulation of p53 and accumulation of its target proteins as well as an increase in p53 mRNA levels, suggesting that these genes are involved in p53 transcription and expression of its target genes followed by p53 protein accumulation. In conclusion, apoptosis and/or autophagy mediated by BIRC4 and TAK1 may be regulated by p53 and caspase activity. These novel findings may provide valuable information that will aid in a better understanding of the roles of caspase-related genes in human cell lines and be useful for the process of drug discovery.
Apoptosis* ; Autophagy* ; Blotting, Western ; Caspases ; Cell Death ; Cell Line ; Cysteine Proteases ; Drosophila ; Drug Discovery ; Genetic Testing ; Humans ; Luciferases ; RNA, Messenger ; Up-Regulation

Paeoniflorin (PAE) is the most abundant compound in Xuebijing injection widely used to treat sepsis. We aimed to investigate effect of PAE on expression of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) in a rat model of sepsis. Wistar rats were divided into Normal, Model, and PAE groups (n=20 each). Endotoxin was administrated at 5 mg/ml/kg in Model and PAE rats to establish rat sepsis model. 1 h after endotoxin administration, PAE was administrated at 4 ml/kg in PAE group once per day for 3 days. Routine blood tests and biochemical indexes were assessed, including aspartate aminotransferase (AST) and creatine kinase-MB (CK-MB). The plasma sTREM-1 level was measured using quantitative ELISA. At the end of experiment, the small intestine, liver, kidney and lung were subjected to pathological examinations. A rat model of sepsis-induced multiple organ dysfunction syndrome (MODS) was established successfully with endotoxin administration (5 mg/ml/kg), evidenced by histo-pathological examinations, routine blood tests and biochemical indexes: platelet count decreased and white blood cell count increased (p<0.05), CK-MB and AST increased (p<0.05). PAE treatment significantly reduced the plasma levels of AST, CK-MB, and sTREM-1, compared to Model group (p<0.05). Meanwhile, sepsis-induced damages in the liver, lung, stomach and intestinal mucosa were also markedly ameliorated by PAE treatment. PAE demonstrated a significantly protective effect in a rat model of sepsis by decreasing plasma sTREM-1 level, reducing inflammation, preventing MODS and protecting organ functions.
Animals ; Aspartate Aminotransferases ; Creatine ; Enzyme-Linked Immunosorbent Assay ; Hematologic Tests ; Inflammation ; Intestinal Mucosa ; Intestine, Small ; Kidney ; Leukocyte Count ; Liver ; Lung ; Models, Animal ; Multiple Organ Failure ; Plasma ; Platelet Count ; Rats* ; Rats, Wistar ; Sepsis ; Stomach

Metabotropic glutamate receptor (mGluR)-dependent long-term depression (LTD), a type of synaptic plasticity, is characterized by a reduction in the synaptic response, mainly at the excitatory synapses of the neurons. The hippocampus and the cerebellum have been the most extensively studied regions in mGluR-dependent LTD, and Group 1 mGluR has been reported to be mainly involved in this synaptic LTD at excitatory synapses. However, mGluR-dependent LTD in other brain regions may be involved in the specific behaviors or diseases. In this paper, we focus on five cortical regions and review the literature that implicates their contribution to the pathogenesis of several behaviors and specific conditions associated with mGluR-dependent LTD.
Brain ; Cerebellum ; Depression* ; Hippocampus ; Neuronal Plasticity ; Neurons ; Receptors, Metabotropic Glutamate* ; Synapses

Myometrial relaxation of mouse via expression of two-pore domain acid sensitive (TASK) channels was studied. In our previous report, we suggested that two-pore domain acid-sensing K⁺ channels (TASK-2) might be one of the candidates for the regulation of uterine circular smooth muscles in mice. In this study, we tried to show the mechanisms of relaxation via TASK-2 channels in marine myometrium. Isometric contraction measurements and patch clamp technique were used to verify TASK conductance in murine myometrium. Western blot and immunehistochemical study under confocal microscopy were used to investigate molecular identity of TASK channel. In this study, we showed that TEA and 4-AP insensitive non-inactivating outward K⁺ current (NIOK) may be responsible for the quiescence of murine pregnant longitudinal myometrium. The characteristics of NIOK coincided with two-pore domain acid-sensing K⁺ channels (TASK-2). NIOK in the presence of K⁺ channel blockers was inhibited further by TASK inhibitors such as quinidine, bupivacaine, lidocaine, and extracellular acidosis. Furthermore, oxytocin and estrogen inhibited NIOK in pregnant myometrium. When compared to non-pregnant myometrium, pregnant myometrium showed stronger inhibition of NIOK by quinidine and increased immunohistochemical expression of TASK-2. Finally, TASK-2 inhibitors induced strong myometrial contraction even in the presence of L-methionine, a known inhibitor of stretch-activated channels in the longitudinal myometrium of mouse. Activation of TASK-2 channels seems to play an essential role for relaxing uterus during pregnancy and it might be one of the alternatives for preventing preterm delivery.
Acidosis ; Animals ; Blotting, Western ; Bupivacaine ; Estrogens ; Female ; Isometric Contraction ; Lidocaine ; Methionine ; Mice* ; Microscopy, Confocal ; Muscle, Smooth ; Myometrium ; Oxytocin ; Pregnancy ; Quinidine ; Relaxation* ; Tea ; Uterine Contraction ; Uterus

Nafamostat mesilate (NM), a synthetic serine protease inhibitor, has anticoagulant and anti-inflammatory properties. The intracellular mediator and external anti-inflammatory external signal in the vascular wall have been reported to protect endothelial cells, in part due to nitric oxide (NO) production. This study was designed to examine whether NM exhibit endothelium dependent vascular relaxation through Akt/endothelial nitric oxide synthase (eNOS) activation and generation of NO. NM enhanced Akt/eNOS phosphorylation and NO production in a dose- and time-dependent manner in human umbilical vein endothelial cells (HUVECs) and aorta tissues obtained from rats treated with various concentrations of NM. NM concomitantly decreased arginase activity, which could increase the available arginine substrate for NO production. Moreover, we investigated whether NM increased NO bioavailability and decreased aortic relaxation response to an eNOS inhibitor in the aorta. These results suggest that NM increases NO generation via the Akt/eNOS signaling pathway, leading to endothelium-dependent vascular relaxation. Therefore, the vasorelaxing action of NM may contribute to the regulation of cardiovascular function.
Animals ; Aorta ; Arginase ; Arginine ; Biological Availability ; Endothelial Cells ; Endothelium ; Human Umbilical Vein Endothelial Cells ; Mesylates* ; Nitric Oxide ; Nitric Oxide Synthase ; Nitric Oxide Synthase Type III ; Phosphorylation ; Rats ; Relaxation ; Serine Proteases ; Vasodilation*

Angiogenesis plays an essential role in embryo development, tissue repair, inflammatory diseases, and tumor growth. In the present study, we showed that endothelial nitric oxide synthase (eNOS) regulates retinal angiogenesis. Mice that lack eNOS showed growth retardation, and retinal vessel development was significantly delayed. In addition, the number of tip cells and filopodia length were significantly reduced in mice lacking eNOS. Retinal endothelial cell proliferation was significantly blocked in mice lacking eNOS, and EMG-2-induced endothelial cell sprouting was significantly reduced in aortic vessels isolated from eNOS-deficient mice. Finally, pericyte recruitment to endothelial cells and vascular smooth muscle cell coverage to blood vessels were attenuated in mice lacking eNOS. Taken together, we suggest that the endothelial cell function and blood vessel maturation are regulated by eNOS during retinal angiogenesis.
Animals ; Blood Vessels ; Embryonic Development ; Endothelial Cells ; Female ; Mice ; Muscle, Smooth, Vascular ; Nitric Oxide Synthase Type III* ; Pericytes ; Pregnancy ; Pseudopodia ; Retina ; Retinal Vessels ; Retinaldehyde* ; Signal Transduction