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An increase in opening of BKCa channels in smooth muscle cells in streptozotocin-induced diabetic mice

Acta Pharmacologica Sinica 2004年第6期25卷 42-48页

作者： Chun-ling YE2, Bing SHEN4, Xian-da REN, Rong-jing LUO3, Sheng-yuan DING3, Fu-man YAN3, Jia-hua JIANG Department of Pharmacology, Pharmacy College of Ji-nan University, Guangzhou 510632 3Department of Physiology, Guangzhou University of Traditional Chinese Medicine, Guangzhou 510407 4Department of Molecular Biology and Cell Biology, School ofLife Sciences, University of Sciences and Technology of China, Hefei 230036, China Department of Pharmacology Pharmacy College of Ji-nan University Guangzhou 510632 Department of Molecular Biology and Cell Biology School of Life Sciences University of Sciences and Technology of China Hefei Department of Physiology Guangzhou University of Traditional Chinese Medicine Guangzhou 510407

AIM: To investigate the changes of function of large conductance of calcium-activated potassium channels (BKCa channels) in thoracic aortic smooth muscle cells in early stage of streptozotocin (STZ)-induced diabetic C57BL/6J mice. METHODS: Vascular muscle tension in the isolated thoracic aortic rings of mice was compared, and the role of BKCa channels in relaxation of isolated mice thoracic aortic rings induced by acetylcholine (ACh) was determined. Meanwhile, single vascular smooth muscle cells (VSMCs) were isolated by collagenase, and BKCa currents were recorded by patch-clamp single channel recording technique in symmetric high potassium solution. RESULTS: Tetraethylammonium (TEA) 1 mmol/L, a selective calcium-activated potassium channel blocker, caused significant rightward shift in the concentration-response curves of ACh in the isolated thoracic aortic rings of diabetic mice and pD2 value of ACh-induced relaxation was decreased notably after TEA treatment [(6.3±0.4) vs (6.9±0.5), n=10 rings from 7 mice, P0.05]. Furthermore, conductance of BKCa channels in single thoracic aortic smooth muscle cells was decreased [(199±15) pS, n=10 cells from 7 mice vs (266±11) pS, n=12 cells from 6 mice, P<0.01], but probability of open of BKCachannels was increased [(0.51±0.28) vs (0.11±0.06), n=6 cells from 6 mice, P<0.01], and the mean closed time in diabetic mice was reduced [(15±15) vs (132±98), n=6 cells from 6 mice, P<0.05]. CONCLUSION: The opening of BKCa channels was increased in thoracic aortic smooth muscle cells in the early stage of STZ-induced diabetic C57BL/6J mice by reducing mean closed time, but the conductance of BKCa channels was decreased.

关键词： diabetes mellitus streptozotocin aorta patch-clamp techniques potassium channels calcium

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Tetrandrine inhibits Ca2+-activated chloride channel in cultured human umbilical vein endothelial cells

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Acta Pharmacologica Sinica 2004年第3期25卷 73-79页

作者： Qi-zhi FANG1,2,Ning ZHONG1,3,Yi ZHANG1,Zhao-nian ZHOU1,4 1Physiological Lab of Hypoxia,Shanghai Institute of BiologicalSciences,Chinese Academy ofSciences,Shanghai200031,China 3Department of Molecular and Cell Biology,University of California at Berkeley,Berkeley,CA 94720,USA 2 Now in CardiovascularResearch Institute,University of Cali- fornia at San Francisco,San Francisco,CA 94143,USA Physiological Laboratory of Hypoxia Shanghai Institutes for Biological Sciences Chinese Academy of Sciences 上海 200031

AIM: To characterize the electrophysiological and kinetic properties of Ca2+-activated chloride channel (CaCC) in cultured human umbilical vein endothelial cell line (HUVEC), and test the inhibitory effects of tetrandrine (Tet) on CaCC. METHODS: Ca2+-activated Cl- currents (ICl,Ca) were recorded by patch-clamp whole cell configurations. [Ca2+]i was measured via intracellular Fura-2 fluorescence intensities. RESULTS: ICl,Ca was activated by increasing [Ca2+]i via direct elevation of intracellular calcium. ICl,Ca showed an apparent outward rectification properties, and it was activated in a voltage- and calcium-dependent mode. Tet dose-dependently inhibited ICl,Ca, the IC50 was (5.2±0.4) μmol/L (n=8 cells). Tet suppressed both voltage-dependent and calcium-dependent activation of ICl,Ca. The activa- tion time constant was (326±12) ms [in the presence of 10 μmol/L Tet, compared to control (175±17) ms, at +100 mV], and Ca2+ concentration for half maximal activation was (387±61) nmol/L for Tet (compared to control (287±36) nmol/L. CONCLUSIONS: Tet effectively blocked ICl,Ca, and such effects might be due to its inhibitory effects on the activation process of Ca2+-activated chloride channel.

关键词： chloride channels endothelium tetrandrine patch-clamp techniques calcium

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Inactivation gating determines drug potency:a common mechanism for drug blockade of HERG channels

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Acta Pharmacologica Sinica 2004年第5期25卷 12-18页

作者： Bao-feng YANG1, Dong-hui XU2, Chao-qian XU, Zhe LI, Zhi-min DU, Hui-zhen WANG, De-li DONGDepartment of Pharmacology, Harbin Medical University, Harbin 150086, China 2Department of Pharmacy, Sun Yat-sen University, Guangzhou 510080, China Department of Pharmacology Harbin Medical University Harbin 150086 Department of Pharmacy Sun Yat-sen University Guangzhou 510080

AIM: To determine the mechanisms of interactions between different drugs and HERG channels. METHODS:Various antiarrhythmic (dofetilide, quinidine, azimilide, RP58866) and non-antiarrhythmic (terfenadine, nicotine)agents were used on HERG channels expressed in Xenopus oocyte. Whole-cell voltage-clamp techniques wereused. RESULTS: All drugs produced concentration-dependent block of HERG current. The inhibition was mark-edly facilitated with voltage protocols favoring channel inactivation (eg, less negative holding potentials). Maneu-vers that weakened channel inactivation (eg, elevation of external K+), relieved HERG blockade by all drugs. Moreover,the inhibitory potency was reduced by at least 20-300 fold with varying compounds when rapid C-type inactivationwas removed by a mutation located between the transmembrane domains 5 and 6 (S631A). CONCLUSION: Theinactivation gating of HERG channels determines the blocking potency of drugs. This mechanism might be com-mon to drugs of various classes.

关键词： antiarrhythmic agents potassium channels mutation channel inactivation patch-clamp techniques oocytes Xenopus

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Modulatory effect of substance P on GABA-activated currents from rat dorsal root ganglion

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Acta Pharmacologica Sinica 2004年第5期25卷 81-87页

作者： Jun-qiang SI2, Zhi-qin ZHANG, Chun-xia LI, Li-feng WANG, Yun-lei YANG3, Zhi-wang LI3Department of Physiology, Medical College Shihezi University, Shihezi 832002, China3 Now in Tongji Medical College, Huazhong University of Sci-ence and Technology, Wuhan 430030, China. Department of Physiology Medical College Shihezi University Shihezi 832002 Tongji Medical College Huazhong University of Science and Technology Wuhan 430030

AIM: To explore the modulatory effect of substance P (SP) on GABA-activated current of dorsal root ganglion(DRG) neurons in rat. METHODS: The whole-cell patch-clamp technique was used to record SP- and GABA-activated currents in neurons freshly dissociated from rat DRG neurons. Drugs were applied by rapid solutionexchange. RESULTS: Application of SP (28/41, 68.5 %) and GABA (36/41, 88.2 %) could induce concentration-dependent inward current in some cells. SP-(10 mol/L) and GABA (100 mol/L)-activated inward currents were(24483) pA (n=9) and (1.80.5) nA (n=13), respectively. The majority of GABA-activated current had obviousthree processes, the peak value (Ip), the steady state (Iss) and the desensitization (Id). The desensitization of GABA-activated current was a biphasic process, including fast and slow desensitization. However, pre-application of SP(0.0011 mol/L) could inhibit the GABA-activated inward current which was identified to be GABAA receptor-mediated current. The inhibitory effects were concentration-dependent. The inhibitory effect of SP on the peakvalue of GABA-activated current was more than the steady state of GABA-activated current. The inhibition ofGABA-activated current by SP (0.1 mol/L) was related to the time after application of SP, the inhibition of GABA-activated currents by SP reached the peak at about 4 min (49.8 %7.2 %, n=7, Ppatch clamp. CONCLUSION: Pre-application of SP exerts a more strong inhibitoryeffect on the peak value of GABA-activated current than the steady state of GABA-activated current.

关键词： patch-clamp techniques spinal ganglia substance P GABA protein kinase C

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Modulating effect of ginseng saponins on heterologously expressed HERG currents in Xenopus oocytes

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Acta Pharmacologica Sinica 2005年第5期26卷 551-558页

作者： Cuk-seongKIM Sook-jinSON Hyo-shinKIM Yong-dukKIM Kyu-seungLEE Byeong-hwaJEON Kwang-jinKIM Jin-kyu PARK Jin-bong PARK Department of Physiology College of Medicine Chungnam National University Daejeon 301-131 Korea Department of Physiology College of Medicine Chungnam National University Daejeon 301-131 Korea Department of Physiology College of Medicine Chungnam National University Daejeon 301-131 Korea Department of Physiology College of Medicine Chungnam National University Daejeon 301-131 Korea Department of Physiology College of Medicine Chungnam National University Daejeon 301-131 Korea Department of Physiology College of Medicine Chungnam National University Daejeon 301-131 Korea Department of Physiology College of Medicine Chungnam National University Daejeon 301-131 Korea Korea Ginseng and Tobacco Research Institute Daejeon 305-805 Korea Department of Physiology College of Medicine Chungnam National University Daejeon 301-131 Korea

Aim:To examine the effects of ginseng saponins on the heterologously expressedhuman ether-a-go-go related gene（HERG）that encodes the rapid component ofthe delayed rectifier K+***:A two-electrode voltage clamp tech-nique was *** currents were recorded in Xenopus oocytes injected withHERG ***:Crude saponins of Korean red ginseng（GS）induced aminimal increase of the maximal HERG conductance without changes in the volt-age-dependent HERG current activation and inactivation ***,however,decelerated HERG current deactivation in a concentration-dependent manner,which was more noticeable with panaxitriol（PT）than panaxidiol（PD）.Consistently,ginseng saponins increased the HERG deactivation time constants with the orderof potency of Rg1（a maj or component of PT）>Rf1>Rb1（a major component of PD）.Re had little effect on HERG *** a cardiac action potential,GSincreased the outward HERG ***:Ginseng saponins enhanceHERG currents,which could be in part a possible mechanism of the shorteningcardiac action potential of ginseng saponins.

关键词： Ginseng saponins Xenopus laevis potassium channels action potentials patch-clamp techniques

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Bradykinin potentiates 5-HT3 receptor-mediated current in rat trigeminal ganglion neurons

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Acta Pharmacologica Sinica 2005年第4期26卷 428-434页

作者： Wang-ping HU~(1,2) Xue-mei LI~2 Ji-liang WU~3 Min ZHENG~3 Zhi-wang LI~4 2 Department of Physiology,3 Department of Pharmacology,Xianning College,Xianning 437100,China 4 Department of Neurobiology,Tongji Medical College of Huazhong University of Science and Technology,Wuhan 430030,China Department of Physiology Xianning College Xianning China Department of Pharmacology Xianning College Xianning China Department of Neurobiology Tongji Medical College of Huazhong University of Science and Technology Wuhan China

Aim:To explore the modulatory effect of bradykinin （BK） on 5-HT3receptor-mediated current in trigeminal ganglion （TG） neurons in ***:The whole-cell patch-clamp technique was used to record 5-HT-activated currents (I5-HT) inneurons freshly dissociated from rat *** were applied by rapid ***:The majority of the neurons examined responded to 5-HTapplied externally with an inward current （76.3%,74/97） that could be blocked bythe 5-HT3receptor antagonist,ICS-205,930 (1×10-6mol/L).In 66 of the 74 cellssensitive to 5-HT （89.2%）,pretreatment for 30 s with BK (1×10-6-1×10-10mol/L)could potentiate I5-HTwith the maximal modulatory effect occurring at10-7mol/L BK （71.6%+4.9%）.BK shifted the 5-HT concentration-response curveupwards with an increase of 68.9%±7.2% in the maximal current response,but withno significant change in the EC50value （19.1±3.2 μmol/L vs 20.9±3.5 μmol/L;t-test,P>0.05;n=8）.BK potentiated I5-HTin a holding potential-independent manner anddid not alter the reverse potential of *** BK-induced potentiation ofI5-HTwas almost completely blocked by Hoe 140 (5×10-7mol/L),a selective B2BKreceptor antagonist,and was removed after intracellular dialysis of GF-109203X（2 μmol/L）,a selective protein kinase C （PKC） inhibitor,with the re-patch ***:Pre-application of BK exerts an enhancing effect on I5-HTvia a PKC-dependent pathway in rat TG neurons,which may explain the peripheral'mecha-nism of pain and hyperalgesia caused by,for example,tissue damage andinflammation.

关键词： bradykinin 5-HT3 serotonin receptor regulation patch-clamp techniques trigeminal ganglion

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Ferulic acid enhances insulin secretion by potentiating L-type Ca^(2+)channel activation

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Journal of Integrative Medicine 2023年第1期21卷 99-105页

作者： Katesirin Ruamyod Wattana B.Watanapa Chanrit Kakhai Pimchanok Nambundit Sukrit Treewaree Parin Wongsanupa Department of Physiology Faculty of Medicine Siriraj HospitalMahidol UniversityBangkok 10700Thailand

Objective To investigate the effect of ferulic acid,a natural compound,on pancreatic beta cell viability,Ca^(2+)channels,and insulin *** 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 *** whole-cell patch-clamp technique and enzyme-linked immunosorbent assay were also used to examine the action of ferulic acid on Ca^(2+)channels and insulin secretion,*** Ferulic acid did not affect cell viability during exposures up to 72 *** electrophysiological study demonstrated that ferulic acid rapidly and concentration-dependently increased L-type Ca^(2+)channel current,shifting its activation curve in the hyperpolarizing direction with a decreased slope factor,while the voltage dependence of inactivation was not *** the other hand,ferulic acid have no effect on T-type Ca^(2+)***,ferulic acid significantly increased insulin secretion,an effect inhibited by nifedipine and Ca^(2+)-free extracellular fluid,confirming that ferulic acid-induced insulin secretion in these cells was mediated by augmenting Ca^(2+)influx through L-type Ca^(2+)*** data also suggest that this may be a direct,nongenomic *** This is the first electrophysiological demonstration that acute ferulic acid treatment could increase L-type Ca^(2+)channel current in pancreaticβcells by enhancing its voltage dependence of activation,leading to insulin secretion.

关键词： Calcium channels,L-type Diabetes mellitus,type2 Ferulicacid Insulin Insulin-secreting cells patch-clamp techniques

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Differential sensitivity of GABAergic and glycinergic inputs to orexin-A in preganglionic cardiac vagal neurons of newborn rats

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Acta Pharmacologica Sinica 2005年第12期26卷 1442-1447页

作者： Ji-jiang WANG~2 Yong-hua CHEN Ke-yong LI Feng-yan SUN National Key Laboratory of Medical Neurobiology,Fudan University Shanghai Medical College,Shanghai 200032,China National Key Laboratory of Medical Neurobiology Fudan University Shanghai Medical College Shanghai China

Aim:To test the effect of orexin-A(hypocretin-1),a neuropeptide synthesized inthe lateral hypothalamus and the perifornical area,on the glycinergic inputs andthe GABAergic inputs of cardiac vagal neurons(CVN).Methods:The effects oforexin-A at three concentrations(20 nmol/L,100 nmol/L,500 nmol/L)on theglycinergic inputs and the GABAergic inputs were investigated by using retro-grade fluorescent labeling of cardiac neurons(CVN)in the nucleus ambiguus(NA)and the voltage patch-clamp ***:Orexin-A dose-depen-dently increased the frequency of both the glycinergic and the GABAergic spon-taneous inhibitory postsynaptic currents(sIPSC).However,at a lower concentra-tion(20 nmol/L)of orexin-A,although the frequency of the glycinergic sIPSC wassignificantly increased,the frequency of the GABAergic sIPSC was not signifi-cantly ***:The glycinergic inputs and the GABAergic inputshave different sensitivities to orexin-A,which suggests that the two kinds ofinhibitory inputs might play different roles in the synaptic control of cardiac vagalfunctions.

关键词： patch-clamp techniques nervous system synaptic transmission vagus nerve

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Effects of AMP579 and adenosine on L-type Ca2+current in isolated rat ventricular myocytes

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Acta Pharmacologica Sinica 2005年第5期26卷 559-562页

作者： Xiong WANG~1,Bo-wei WU,Dong-mei WUDepartment of Physiology Shanxi Medical University,Taiyuan 030001,China Department of Physiology Shanxi Medical University Taiyuan China

Aim:To compare the effects of AMP579 and adenosine on L-type Ca2+current(ICa-L)in rat ventricular myocytes and explore the mechanism by which AMP579acts on ***:ICaLwas recorded by patch-clamp technique in ***:Adenosine(10nmol/L to 50μmol/L)showed no effect onbasal ICaL,but it inhibited the ICaLinduced by isoproterenol 10 nmol/L in a concen-tration-dependent manner with the IC50of 13.06 μmol/*** to adenosine,AMP579 also showed an inhibitory effect on the ICaLinduced by ***579 and adenosine(both in 10 μmol/L)suppressed isoproterenol-inducedICaLby 11.1% and 5.2%, *** addition,AMP579 had a direct inhibitoryeffect on basal ICaLin a concentration-dependent manner with IC50(1.17 μmol/L).PD 116948(30μmol/L),an adenosine A1receptor blocker,showed no action on theinhibitory effect of AMP579 on basal ***,GF109203X(0.4μmol/L),aspecial protein kinase C(PKC)blocker,could abolish the inhibitory effect of AMP579on basal I*** the inhibitory effect of AMP579 on basal ICaLwas inducedthrough activating PKC,but not linked to adenosine ***:AMP579 shows a stronger inhibitory effect than adenosine on the ICaLinducedby ***579 also has a strong inhibitory effect on basal ICaLin ratventricular *** of PKC is involved in the inhibitory effect ofAMP579 on basal ICaLat downstream-mechanism.

关键词： AMP579 adenosine heart ventricles cardiac myocytes L-type calcium channels patch-clamp techniques

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Effect of didrovaltrate on l-calcium current in rabbit ventricular myocytes

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Journal of Traditional Chinese Medicine 2012年第3期32卷 442-445页

作者： Qiang Xie Weihua Li ZhengRong Huang Ziguan Zhang Department of Cardiology the First Affiliated Hospital of Xiamen UniversityXiamen 361003China

OBJECTIVE:To investigate the effect of didrovaltrate on L-type calcium current(I Ca-L) in rabbit ventricular ***:We used the whole cell patch clamp recording ***:Didrovaltrate at concentrations of 30 μg/L and 100 μg/L significantly decreased peak I Ca-L(I Ca-Lmax) from(6.01±0.48) pA/pF to(3.45±0.27) pA/pF and(2.16 ± 0.19) pA/pF(42.6% and 64.1%,n=8,P< 0.01),*** shifted upwards the current-voltage curves of I Ca-L without changing their active,peak and reverse *** affected the steady-state inactivation of I *** half activation potential(V 1/2) was significantly shifted from(-26 ± 2) to(-36 ± 3) mV(n=6,P<0.05),with a significant change in the slope factor(k)(from 8.8 ± 0.8 to 11.1 ± 0.9,n=6,P<0.05).Didrovaltrate did not affect the activation ***:Didrovaltrate blocks I Ca-L in a concentration-dependent manner and probably inhibits I Ca-L in its inactive state,which may contribute to its cardiovascular effect.

关键词： Didrovaltrate patch-clamp techniques Calcium channels,L-Type Myocytes Cardiac

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