Ferulic acid enhances insulin secretion by potentiating L-type Ca2+ channel activation / 中西医结合学报

OBJECTIVE@#To investigate the effect of ferulic acid, a natural compound, on pancreatic beta cell viability, Ca2+ channels, and insulin secretion.@*METHODS@#We studied the effects of ferulic acid on rat insulinoma cell line viability using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide viability assay. The whole-cell patch-clamp technique and enzyme-linked immunosorbent assay were also used to examine the action of ferulic acid on Ca2+ channels and insulin secretion, respectively.@*RESULTS@#Ferulic acid did not affect cell viability during exposures up to 72 h. The electrophysiological study demonstrated that ferulic acid rapidly and concentration-dependently increased L-type Ca2+ channel current, shifting its activation curve in the hyperpolarizing direction with a decreased slope factor, while the voltage dependence of inactivation was not affected. On the other hand, ferulic acid have no effect on T-type Ca2+ channels. Furthermore, ferulic acid significantly increased insulin secretion, an effect inhibited by nifedipine and Ca2+-free extracellular fluid, confirming that ferulic acid-induced insulin secretion in these cells was mediated by augmenting Ca2+ influx through L-type Ca2+ channel. Our data also suggest that this may be a direct, nongenomic action.@*CONCLUSION@#This is the first electrophysiological demonstration that acute ferulic acid treatment could increase L-type Ca2+ channel current in pancreatic β cells by enhancing its voltage dependence of activation, leading to insulin secretion.

Relationship between MCU-mediated mitochondrial dynamics and intestinal ischemia-reperfusion injury in mice / 中华麻醉学杂志

Objective:To evaluate the relationship between mitochondrial calcium uniporter protein (MCU)-mediated mitochondrial dynamics and intestinal ischemia-reperfusion (I/R) injury in mice.Methods:Twenty-four wild-type adult male C57BL/6J mice, aged 6-8 weeks, weighing 18-20 g, were divided into 4 groups ( n=6 each) using a random number table method: sham operation group (S group), intestinal I/R group (IIR group), sham operation+ MCU inhibitor Ru360 group (S+ Ru360 group) and intestinal I/R + Ru360 group (IIR+ Ru360 group). The mouse model of intestinal I/R injury was prepared by clamping the root of the superior mesenteric artery for 45 min followed by 2 h of reperfusion in anesthetized animals. Small intestinal tissues were obtained at the end of reperfusion for examination of the intestinal mucosal injury which was scored according to Chiu and for determination of the content of malondialdehyde (MDA) (TBA method), activity of superoxide dismutase (SOD) (WST-8 method), content of lactic dehydrogenase (LDH) (colorimetric method), and expression of MCU, dynamin-related protein 1 (Drp1), recombinant human mitochondrial fission 1 protein (Fis1), mitofusin-1 (Mfn1) and Mfn2 (by Western blot). Results:Compared with S and S+ Ru360 groups, the Chiu′s score and contents of MDA and LDH were significantly increased, the activity of SOD was decreased, the expression of MCU, Drp1 and Fis1 was up-regulated, and the expression of Mfn1 and Mfn2 was down-regulated in IIR and IIR+ Ru360 groups ( P<0.05). Compared with IIR group, the Chiu′s score and contents of MDA and LDH were significantly decreased, the activity of SOD was increased, the expression of MCU, Drp1 and Fis1 was down-regulated, and the expression of Mfn1 and Mfn2 was up-regulated in IIR+ Ru360 group ( P<0.05). Conclusions:The mechanism underlying intestinal I/R injury may be related to MCU-induced promotion of mitochondrial fission, reduction of mitochondrial fusion and mediation of imbalance in mitochondrial dynamics in mice.

Analgesic effects of Phα1ß toxin: a review of mechanisms of action involving pain pathways

Phα1ß is a neurotoxin purified from spider venom that acts as a high-voltage-activated (HVA) calcium channel blocker. This spider peptide has shown a high selectivity for N-type HVA calcium channels (NVACC) and an analgesic effect in several animal models of pain. Its activity was associated with a reduction in calcium transients, glutamate release, and reactive oxygen species production from the spinal cord tissue and dorsal ganglia root (DRG) in rats and mice. It has been reported that intrathecal (i.t.) administration of Phα1ß to treat chronic pain reverted opioid tolerance with a safer profile than ω-conotoxin MVIIA, a highly selective NVACC blocker. Following a recent development of recombinant Phα1ß (CTK 01512-2), a new molecular target, TRPA1, the structural arrangement of disulphide bridges, and an effect on glial plasticity have been identified. CTK 01512-2 reproduced the antinociceptive effects of the native toxin not only after the intrathecal but also after the intravenous administration. Herein, we review the Phα1ß antinociceptive activity in the most relevant pain models and its mechanisms of action, highlighting the impact of CTK 01512-2 synthesis and its potential for multimodal analgesia.

Analgesic effects of Phalfa1 beta toxin: a review of mechanisms of action involving pain pathways

Phα1ß is a neurotoxin purified from spider venom that acts as a high-voltage-activated (HVA) calcium channel blocker. This spider peptide has shown a high selectivity for N-type HVA calcium channels (NVACC) and an analgesic effect in several animal models of pain. Its activity was associated with a reduction in calcium transients, glutamate release, and reactive oxygen species production from the spinal cord tissue and dorsal ganglia root (DRG) in rats and mice. It has been reported that intrathecal (i.t.) administration of Phα1ß to treat chronic pain reverted opioid tolerance with a safer profile than ω-conotoxin MVIIA, a highly selective NVACC blocker. Following a recent development of recombinant Phα1ß (CTK 01512-2), a new molecular target, TRPA1, the structural arrangement of disulphide bridges, and an effect on glial plasticity have been identified. CTK 01512-2 reproduced the antinociceptive effects of the native toxin not only after the intrathecal but also after the intravenous administration. Herein, we review the Phα1ß antinociceptive activity in the most relevant pain models and its mechanisms of action, highlighting the impact of CTK 01512-2 synthesis and its potential for multimodal analgesia.

Analgesic effects of Ph1 toxin: a review of mechanisms of action involving pain pathways

Abstract Ph1 is a neurotoxin purified from spider venom that acts as a high-voltage-activated (HVA) calcium channel blocker. This spider peptide has shown a high selectivity for N-type HVA calcium channels (NVACC) and an analgesic effect in several animal models of pain. Its activity was associated with a reduction in calcium transients, glutamate release, and reactive oxygen species production from the spinal cord tissue and dorsal ganglia root (DRG) in rats and mice. It has been reported that intrathecal (i.t.) administration of Ph1 to treat chronic pain reverted opioid tolerance with a safer profile than -conotoxin MVIIA, a highly selective NVACC blocker. Following a recent development of recombinant Ph1 (CTK 01512-2), a new molecular target, TRPA1, the structural arrangement of disulphide bridges, and an effect on glial plasticity have been identified. CTK 01512-2 reproduced the antinociceptive effects of the native toxin not only after the intrathecal but also after the intravenous administration. Herein, we review the Ph1 antinociceptive activity in the most relevant pain models and its mechanisms of action, highlighting the impact of CTK 01512-2 synthesis and its potential for multimodal analgesia.

Research progress of T-type calcium channel in cancer / 中国医师杂志

In most non-excited cells, voltage-gated T-type calcium channels present three properties of activation, inactivation and slow inactivation, thus contribute to cellular calcium signaling and membrane potential. By which T-type calcium channels play an important role in many cancer cellular processes such as cell proliferation, differentiation, apoptosis, invasion, and metastasis. Inhibiting T-type calcium channels by drugs or genetic tools can change the related cellular currents and the intracellular Ca 2+ , thereby regulating the biological tumorigenesis. This article reviews the electrophysiological of T-type calcium channels during tumor progression, aims to provide a scientific basis for the study and treatment in cancer.

Sex Differences in Electrophysiological Properties of Mouse Medial Preoptic Area Neurons Revealed by In Vitro Whole-cell Recordings / 神经科学通报·英文版

Despite extensive characterization of sex differences in the medial preoptic area (mPOA) of the hypothalamus, we know surprisingly little about whether or how male and female mPOA neurons differ electrophysiologically, especially in terms of neuronal firing and behavioral pattern generation. In this study, by performing whole-cell patch clamp recordings of the mPOA, we investigated the influences of sex, cell type, and gonadal hormones on the electrophysiological properties of mPOA neurons. Notably, we uncovered significant sex differences in input resistance (male > female) and in the percentage of neurons that displayed post-inhibitory rebound (male > female). Furthermore, we found that the current mediated by the T-type Ca

Experimental Studies to Define the Role of Calcium (Ca2+) and Voltage-Gated Calcium Channel Blockers (vCa-CCB) against Neurosteroid Induced Obesity

Introduction:Obesity is closely associated with various types of illness, primarily caused by more calorie intake than body burn. In adipocytes, Calcium (Ca2+) is an important second messenger involved in theregulation of many physiological functions which are essential for survival. In the present research, we have investigated the role of Ca2+ions in obesity by manipulating cytosolic Ca2+ion concentration by selective blocking/advancing the Ca2+ions through the voltage-gated calcium channels. Voltage-gated calcium channel (vCa) plays a key role in regulating intracellular and extracellular Ca2+concentration.Cytoplasmic level of Ca2+was manipulated by supplying calcium carbonateand by using vCa blockers i.e. nifedipine-(N-type-vCa-CCB) and ethosuximide (T-type, vCa-CCB).Methods:Obesity was induced by progesterone in female mice and test drugs were co-administered with progesterone whereas sibutramine was used as standard. The treatment was carried out for 28 days, during and afterthetreatment periodvarious parameters were studied viz food consumption, change in body weight and temperature, the effect on WAT (white adipose tissue, adiposity index, histology of fat pad) and fecal lipid content.Results:Calcium carbonate treated group has shown promising effects in the decrease in body weight by increasing fecal lipid content and lipolysis which was reflected by an increase in body temperature. Ethosuximide also offered significant protection by decreasing the food intake but has not shown any notable effect on fecal fat content, whereas nifedipine has not offered any protection against the obesity induced by neurosteroid.Conclusion:Calcium carbonate has significant anti-obesity activity by including thermogenesis, and increasing fecal lipid content

Endothelium-Independent Vasorelaxant Effects of Anthocyanins-Enriched Extract from Odontonema strictum (Nees) Kuntze (Acanthaceae) Flowers: Ca2+ Channels Involvement

Aims: We aimed in this study to investigate the mechanisms of the vasorelaxation effect caused by the anthocyanins-enriched extract of Odontonema strictum flowers. Study Design: Anthocyanins-enriched extract of Odontonema strictum flowers and vasorelaxantes activities of mice aortic rings. Place and Duration of Study: The flowers of Odontonema strictum (Nees) Kuntze (Acanthaceae) were collected in January 2015 at the “Institut de Recherche en Sciences de la Santé (IRSS)” experimental station in Ouagadougou. The experiments were conducted in October - November 2018 at the department of Medicine and Traditional Pharmacopeia-Pharmacy (MEPHATRA-PH)/IRSS. Methodology: The extract was enriched in anthocyanins using Amberlite XAD-7 non-ionic resin column. The vasorelaxant activity of anthocyanins-enriched extract of O. strictum flowers (OSF) was tested using isolated organ-chamber technique with mice aorta rings. Results: OSF showed concentration-dependent relaxant effects on mice endothelium intact or denuded aortic rings pre-contracted with U46619 (10-7 M) and KCl (80 mM). OSF induced relaxation in the mice aortic rings by stimulating smooth muscle cells. The vasorelaxant effect of OSF (10-1000 µg/mL) was similar in endothelium-intact and endothelium-denuded aortic rings. The maximum relaxant effect was 93.78 ± 4.69% and 92.30 ± 3.19% for endothelium-intact and endothelium-denuded aortic rings, respectively. Moreover, after incubation of the aorta rings with OSF (400 µg/mL) or vehicle (0.02% of DMSO) in PSS, OSF blocked the contraction through mechanism involving inhibition of CaCl2 and U46619 effect. Conclusions: The present study provides a pharmacological evidence for the antihypertensive medicinal use of Odontonema strictum by highlighting its vasorelaxant activity.

Envolvimento das células da glia na ação antinociceptiva da toxina phα1ß e da ω-conotoxina mviia na dor inflamatória periférica / Involvement of glial cells in the antinociceptive action of phα1ß toxin and ω-conotoxin mviia in peripheral inflammatory pain

A lesão inflamatória de origem periférica aumenta a sensibilidade sensória a um estímulo mecânico de leve intensidade, provocando dor, um processo conhecido como alodinia. A recente descoberta de que astrócitos e micróglia da medula espinal tornam-se reativos devido à inflamação periférica, sugere que a glia deve estar envolvida na manifestação patológica da dor. Nesta tese, observou-se que a inflamação periférica, induzida pela injeção intraplantar do adjuvante completo de Freund (CFA), causa alodinia mecânica assim como mudanças na glia. Dentre essas mudanças destacamos o aumento de marcadores específicos da glia, aumento da proliferação de astrócitos assim como alterações morfológicas na micróglia, todas elas características do fenótipo reativo da glia. Além disso, este estudo descobriu que a injeção intratecal da toxina de aranha Phα1ß, um peptídeo com ação analgésica que bloqueia canais de cálcio dependente de voltagem (VGCC), reverte todas as alterações da glia da medula espinal causadas pela inflamação periférica. Essas observações, em resumo, sugerem que a toxina Phα1ß, além de sua já reconhecida ação analgésica, também possui efeitos anti-inflamatórios sobre a plasticidade glial.

A peripheral inflammatory injury increases the mechanical sensitivity in response to light-touch, also named as allodynia. The discovery that spinal astrocytes and microglia become reactive to the peripheral inflammation suggests that the glia presumably engage with the pain pathophysiology. Here, we found that the peripheral inflammation induced by intraplantar injection of complete Freund's adjuvant (CFA) produce mechanical allodynia and robust changes in the spinal glial. Among these changes we found an increase of specific glial markers, increment of astrocytes proliferation, elevation of microglia density and morphologic changes, all of them compatible with the glia reactive phenotype. Moreover, we found that intrathecal injection with the analgesic Phα1ß spider toxin, a voltage-gated calcium channel (VGCC) blocker, reverses all the glial pathological features of the peripheral inflammation. We therefore suggest that the Phα1ß toxin, apart from its notable analgesic effects, is also a potent anti-inflammatory compound acting on glial plasticity.

Antidiarrheal potential of Distemonanthus benthamianus Baillon. extracts via inhibiting voltage-dependent calcium channels and cholinergic receptors

Objective: To evaluate spasmolytic mechanisms of aqueous and methanolic extracts from Distemonanthus benthamianus trunk-bark. Methods: Spasmolytic activities of extracts were evaluated in vitro on spontaneous and potassium chloride-induced jejunum contractions, or against cholinergic [acetylcholine (0.3μmol/L)] stimulations. High performance liquid chromatography analysis of both extracts was performed in reference to standard compounds. Results: Extracts developed concentration-dependent inhibitory activities. The methanolic extract, which revealed better activity, produced spasmolytic and myorelaxant effects at concentrations of 0.01-0.30 mg/mL with EC50 of 0.06 and 0.09 mg/mL (95％ CI: 0.03-0.3 mg/mL), respectively. Its anticholinergic effect was obtained at the same concentrations with EC50 of 0.11 mg/mL (95％ CI:0.03-0.3 mg/mL). Chromatograms showed the presence of gallic acid in both extracts, rutin being only detected in the aqueous extract. Conclusions: Distemonanthus benthamianus extracts exhibit verapamil and atropine-like activities, thus highlighting calcium channels and muscarinic receptors blocking potentials, which may be conveyed by some phenolic compounds. These results confirm the antidiarrheal activity of Distemonanthus benthamianus extracts.

Regulation mechanism of calcium homeostasis in vascular endothelial cells ／ / 心血管康复医学杂志

:Vascular endothelial cells are the barrier of blood vessels .Endothelial injury will lead to occurrence of multiple diseases ,whose mechanism is related to intracellular calcium signal pool regulation .Ca2+ is a secondary messenger for information delivery inside and outside cells ,it initiates endothelial cell signals and plays an important role in controlling vascular tension and endothelial permeability .Study on mechanism of vascular endothelial cell in‐jury has become a hot topic in recent years ,and calcium homeostasis imbalance is the key factor ,whose mechanism is still not clear .The present article reviewed regulating mechanisms of vascular endothelial cytoplasmic membrane calcium transport and intracellular calcium pool regulation , aimed at providing new thinking for prevention and treatment of calcium regulation related diseases .

A Computational Modeling Reveals That Strength of Inhibitory Input, E/I Balance, and Distance of Excitatory Input Modulate Thalamocortical Bursting Properties

The thalamus is a brain structure known to modulate sensory information before relaying to the cortex. The unique ability of a thalamocortical (TC) neuron to switch between the high frequency burst firing and single spike tonic firing has been implicated to have a key role in sensory modulation including pain. Of the two firing modes, burst firing, especially maintaining certain burst firing properties, was suggested to be critical in controlling nociceptive behaviors. Therefore, understanding the factors that influence burst firing properties would offer important insight into understanding sensory modulation. Using computational modeling, we investigated how the balance of excitatory and inhibitory inputs into a TC neuron influence TC bursting properties. We found that intensity of inhibitory inputs and the timing of excitatory input delivery control the dynamics of bursting properties. Then, to reflect a more realistic model, excitatory inputs delivered at different dendritic locations—proximal, intermediate, or distal—of a TC neuron were also investigated. Interestingly, excitatory input delivered into a distal dendrite, despite the furthest distance, had the strongest influence in shaping burst firing properties, suggesting that not all inputs equally contribute to modulating TC bursting properties. Overall, the results provide computational insights in understanding the detailed mechanism of the factors influencing temporal pattern of thalamic bursts.

Docosahexaenoic acid reduces adenosine triphosphate-induced calcium influx via inhibition of store-operated calcium channels and enhances baseline endothelial nitric oxide synthase phosphorylation in human endothelial cells

Docosahexaenoic acid (DHA), an omega-3-fatty acid, modulates multiple cellular functions. In this study, we addressed the effects of DHA on human umbilical vein endothelial cell calcium transient and endothelial nitric oxide synthase (eNOS) phosphorylation under control and adenosine triphosphate (ATP, 100 µM) stimulated conditions. Cells were treated for 48 h with DHA concentrations from 3 to 50 µM. Calcium transient was measured using the fluorescent dye Fura-2-AM and eNOS phosphorylation was addressed by western blot. DHA dose-dependently reduced the ATP stimulated Ca²⁺-transient. This effect was preserved in the presence of BAPTA (10 and 20 µM) which chelated the intracellular calcium, but eliminated after withdrawal of extracellular calcium, application of 2-aminoethoxy-diphenylborane (75 µM) to inhibit store-operated calcium channel or thapsigargin (2 µM) to delete calcium store. In addition, DHA (12 µM) increased ser1177/thr495 phosphorylation of eNOS under baseline conditions but had no significant effect on this ratio under conditions of ATP stimulation. In conclusion, DHA dose-dependently inhibited the ATP-induced calcium transient, probably via store-operated calcium channels. Furthermore, DHA changed eNOS phosphorylation suggesting activation of the enzyme. Hence, DHA may shift the regulation of eNOS away from a Ca²⁺ activated mode to a preferentially controlled phosphorylation mode.

Effects of n-3 polyunsaturated fatty acid on store-operated calcium channels in coronary artery smooth muscle cells derived from diabetic rat / 中华心血管病杂志

Objective@#To investigate the impact of n-3 polyunsaturated fatty acid (n-3 PUFA) on function and expression of store-operated calcium channels (SOCC) in coronary artery smooth muscle cells (SMC) derived from diabetic rat.@*Methods@#A total of 180 healthy male Sprague-Dawley (SD) rats were randomly divided into normal group (N, n=45), placebo-treated diabetic group (D, n=45), lose dose n-3 PUFA treated diabetic group (DL, n=45) and high dose n-3 PUFAs treated diabetic group (DH, n=45). Streptozotocin-induced diabetic rat animal model was established by two consecutive intraperitoneal injections. After modeling, rats in group DL and DH were treated with 10 mg·kg-1·d-1 and 50 mg·kg-1·d-1 n-3 PUFAs respectively per gavage for eight weeks. After eight weeks, rat coronary artery SMC was isolated by enzyme digestion. Changes of cytosolic calcium concentration in coronary artery SMC were examined by calcium fluorescence imaging technique, coronary artery tension was detected by myograph system, and protein expressions of SOCC on coronary artery SMC were measured by Western blot.@*Results@#SOCC induced ΔF340/F380 of group N, D, DL and DH were 0.425±0.023, 0.838±0.037, 0.342±0.052 and 0.364±0.045 respectively, which was significantly lower in group N, DL, DH than in group D (P<0.05). SOCC induced changes of tensions were 0.94±0.09, 1.95±0.18, 1.35±0.24 and 1.01±0.18 in the group N, D, DL and DH, respectively, which was significantly lower in group N and DH than in group D (P<0.05). Protein expressions of STIM1, Orai1 and TRPC1 were significantly higher in diabetic rat coronary SMC than in group N (P<0.05). STIM1 protein expressions were significantly lower in group DL and DH than in group D, and Orai1 and TRPC1 protein expressions were similar among group.@*Conclusions@#Coronary artery tension, cytosolic calcium concentration and protein expressions of SOCC are higher in diabetic rat coronary artery SMC when compared with normal rats. n-3 PUFA intervention could downregulate the protein expression of SOCC, reduce cytosolic calcium concentration and coronary artery tension, and is protective to the diabetic injury in coronary artery.

Effects and mechanism of digoxin on atrium electrical remodeling and susceptibility of atrial fibrillation in aged rabbits / 中华心血管病杂志

Objective@#To investigate the effects and mechanism of digoxin on atrium electrical remodeling and susceptibility of atrial fibrillation (AF) in aged rabbits.@*Methods@#Twenty aged male New Zealand rabbits were divided into aged group and aged plus digoxin group (n=10 each). Electrical parameters including heart rate (HR), RR and QT interval, ST segment and P wave dispersion from normal Ⅱ electrocardiogram, and the maximum upstroke velocity (Maxdv/dt), plateau potential (plateau P), action potential duration of 10%, 20% and 90% (APD10, APD20, APD90) from recording of monophasic action potential (MAP), as well as atrial effective refractory period (AERP200) and dispersion (dERP200) with 200 ms of basic cycle length (BCL), and frequency self adaptation of AERP with 300 ms and 150 ms of BCLs (fERP) were recorded and compared between the 2 groups. BCLs and inducibility of AF post programmed electrical stimulation and Burst-pacing in left atrium tissue of rabbits in vivo were also analyzed. The L-type calcium current (ICa-L) in 2 groups were recorded via whole-cell patch clamp technique, and the fluorescence intensity of intracellular free Ca2+ was detected with Flup-3/AM loading by the laser scanning confocal microscope in enzymatically dissociated single rabbit atrial myocytes.@*Results@#Compared with aged group, the heart rate was faster, RR and QT interval were obvious shorter, ST segment was raised and P wave dispersion was significantly increased in aged plus digoxin group (all P<0.05). Moreover, compared with aged group, the Maxdv/dt and plateau P were obviously increased, APD10 and APD20 were significantly prolongated, and APD90 was significantly shorter in aged plus digoxin group (all P<0.01). Otherwise, the fERP was markedly increased (0.81±0.15 vs. 0.67±0.05), and the induced rate of AF was obviously higher in aged plus digoxin group than in aged group (6/8 vs. 4/9) (all P<0.01). With voltage clamp model, digoxin significantly increased ICa-L of atrial myocytes of aged rabbits, When command potential was 10 mV, the current densities of ICa-L were significantly higher in digoxin group than that in aged group ((15.45±2.38) pA/pF vs. (7.03±1.69) pA/pF, P<0.01). Otherwise, the I-V curve of ICa-L was downward shifted of all I-V curves in digoxin perfused aged atrial cells of rabbits. Moreover, the fluorescence intensities of intracellular free Ca2+ was significantly higher in aged plus digoxin group than in aged group ((1 748±173) μmol/L vs. (478.13±87.63) μmol/L, P<0.01).@*Conclusion@#Digoxin could aggravate the atrial electrical remodeling in atrium of aged rabbits, facilitate susceptibility of atrial fibrillation in aged rabbit, increased current density of ICa-L and concentration of intracellular free Ca2+, followed Ca2+ overload and oscillations might be part of the underlying mechanisms.

Role and Mechanism of Visfatin in Dysfunction of Colonic Smooth Muscle Contraction in Rats / 胃肠病学

Background: Obesity is associated with many functional gastrointestinal disorders, such as gastrointestinal motility disorder. Previous studies showed that adipose tissue-derived adipokine visfatin (VF), which increased in obesity, might impair myometrial contractility and cause vascular smooth muscle relaxation. Aims: To investigate the effect of VF on contractility of colonic smooth muscle in rats and its underlying mechanism. Methods: Segments of distal colon from normal Sprague-Dawley (SD) rats were dissected into strips (0.3 cm × 0.8 cm), and the effect of VF on contractility of muscle strips was measured by biological signal collection system. In in vitro study, colonic smooth muscle cells (SMCs) from neonatal SD rats were cultured and treated with VF; phosphorylation of myoglobulin light chain (MLC) and expression of calcium channel protein Cav1.2 (α1 subunit) were assessed by Western blotting. Cultured in buffer solution with or without calcium, the acetylcholine-stimulated intracellular Ca2+ level in SMCs was detected by confocal laser scanning microscopy. Results: In muscle strip contractility assay, VF (200 ng/mL) significantly inhibited the contractility of colonic smooth muscle strip from normal adult rats (P<0.05). In cultured colonic SMCs, VF (200 ng/mL) down-regulated the calcium channel protein Cav1.2 expression and reduced the intracellular Ca2+ level and MLC phosphorylation (P<0.05). Conclusions: VF may down-regulate the expression of calcium channel protein Cav1.2 on the membrane of colonic SMCs and cause colonic dysmotility by interfering with Ca2+ signaling and smooth muscle contractility.

Progress in Study on Ion Channel and Pathogenesis of Irritable Bowel Syndrome / 胃肠病学

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder, mainly manifested as recurrent abdominal pain, abdominal discomfort and/or changes of defecation habits and stool character, its pathogenesis has not been fully clarified. The pathophysiology is characterized by visceral hypersensitivity, abnormal intestinal motility, and so on. Abnormality of ion channels may be in involved in the pathophysiological mechanism of IBS. This article reviewed the progress in study on ion channels and pathogenesis of IBS.

Effect of 17β-estradiol on Ca2+ channels during osteogenic differentiation of rat bone marrow mesenchymal stem cells / 吉林大学学报(医学版)

Objective: To observe the effect of 17β-estradiol (17β-E2) on the calcium (Ca2) channels during the osteogenic differentiation of rat bone marrow mesenchymal stem cells (MSCs), and to elucidate the mechanism of 17β-E2 in the osteogenic differentiation of MSCs. Methods: The MSCs were separated by density gradient centrifugation and adherent screening, and passaged for 3 times continuously to induce osteoblast differentiation. The MSCs were divided into control group [cultivated in osteoblast culture medium alone (OBM)] and different doses of 17β-E2 groups (added with 0. 1, 1.0, 10. 0, and 100. 0 pmol · L-1 17β-E2 in OBM, respectively). On the 14th day of osteogenic induction, the cells in each group were stained with Fluo-3/AM, and the Ca2 levels were determinated by laser scanning confocal microscope; the mean fluorescence intensity (MFD was used to respresent the level of Ca2. Whole-cell Ca2 currents were recorded using whole-cell patch clamp technique under different conditions. Results: The MSCs with fibroblast-like cells, oval nuclei and visible nucleoli were successfully isolated by density gradient centrifugation and adherent screening. The subcultured MSCs grew vigorously and maintained the morphological characteristics of primary cells. Following the increase of 17β-E2 concentration, the Fluo-3 fluorescence staining intensity of Ca2 in each group was also gradually increased, especially in 100. 0 pmol · L-1 17β-E2 group. Compared with control group, the MFI of Ca' and the current peak values of Ca' in 10. 0 and 100. 0 pmol · L-1 17β-E2 groups were increased (P0. 05). Conclusion: The cells isolated by density gradient and adherent screening method are the rat MScs. 17β-E2 plays a role in promoting osteogenesis by enhancing the opening of Ca' channels in the MSCs and the inward current of calcium ions in a dose-dependent manner.