甲苯喹哌对培养爪蟾胚胎肌细胞和神经细胞离子通道的作用

研究新型抗心律失常药甲苯喹哌对离子通道的作用。通过膜片钳技术记录培养爪蟾胚胎肌细胞和神经细胞全细胞的钠通道，其ＩＣ５０为７．２μｍｏｌＬ＾－１（５．３－９．８μｍｏｌＬ＾－１）。甲苯硅派（１０μｍｏｌＬ＾－１）可抑制神经细胞的高电压激活的钙通道。然而，肌细胞上的稳态外向钾电流却受甲苯喹哌的激活。甲苯喹哌抑制钠、钙通道、但激活稳态外向钾通道。     

雌二醇抑制豚鼠心室肌细胞内向整流和延迟整流钾通道电流

目的:研究雌二醇(Estradiol,Est)对心室肌细胞动作电位(AP)、内向整流钾通道电流(I_(K1))及延迟整流钾通道电流(I_K)的影响。方法:全细胞膜片箝技术。结果:EST 10μmol·L~(-1)使豚鼠心室肌细胞AP时程明显缩短,APD_(50)由给药前(474±71)ms缩短至(330±75)ms(P<0.05),Est 100μmol·L~(-1)使APD_(50)缩短至(229±67)ms(P<0.01),使APD_(90)由(587±60)ms缩短至(418±79)ms(P<0.05)。Est浓度依赖性地抑制I_K尾电流(I_K·tail),10μmol·L~(-1)浓度下,I_K·tail减少53％(P<0.05),100μmol·L~(-1)浓度下,I_K·tail减少80％(P<0.05)。10μmol·L~(-1)以上浓度Est明显抑制I_(K1),在-100mV刺激电压下,内向电流最大抑制为49％(P<0.01);在-40mV刺激电压下,外向电流最大抑制为72％(P<0.01)。同时,Est使I_(K1)翻转电位向负电位方向移位(由-70mV变为-76mV)。结论:Est对豚鼠心室肌细胞I_(K1)和I_K通道具有明显的抑制作用。     

DDPH抑制豚鼠单个心室肌细胞L-钙电流和钠电流(英文)

目的:研究1-(2,6-二甲基苯氧基)-2-(3,4-二甲氧基苯乙氨基)丙烷盐酸盐(DDPH)对豚鼠心室肌细胞L-型钙电流和钠电流的作用。方法:全细胞膜片箝技术。结果:(1)DDPH(3-300μmol·L~(-1))浓度依赖性地抑制L-型钙电流,IC_(50)为28.5μmol·L~(-1)(95％可信限:14.3-42.7μmol·L~(-1))。维拉帕米0.3-30μmol/L浓度依赖性地抑制钙电流,IC_(50)为1.8μmol·L~(-1)(95％可信限:1.3-2.3μmol·L~(-1))。美西律100μmol·L~(-1)对钙电流无影响。DDPH30μmol·L~(-1)使用依赖性阻滞钙电流,1Hz时抑制率为58％±13％(n=5,P<0.01),3Hz时为76％±11％(n=5,P<0.01)。(2)DDPH(20-320μmol·L~(-1))浓度依赖性抑制钠电流,IC_(50)为89.0μmol·L~(-1)(95％可信限:68.7-109.3μmol·L~(-1))。美西律抑制钠电流的IC_(50)为32.2μmol·L~(-1)(95％可信限:11.7-52.7μmol·L~(-1))。维拉帕米10μmol·L~(-1)对钠电流无影响(P>0.05).DDPH80μmol·L~(-1)对钠电流无使用依赖性阻滞。结论:DDPH抑制豚鼠心室肌细胞L-型钙电流和钠电流,但抑制钙电流的作用弱于维拉帕米,抑制钠电流的作用弱于美西律。     

大豆苷元对大鼠心室肌细胞I_(Na)的影响

目的观察大豆苷元对大鼠心室肌细胞钠通道电流(I_(Na))的影响,探讨其抗心律失常的机制。方法 MTT比色法检测大豆苷元对心室肌细胞活力的影响;单酶解法分离大鼠单个心室肌细胞;全细胞膜片钳技术观察、记录、分析大豆苷元给药前后大鼠心室肌细胞I_(Na)及其动力学特征的变化。结果 MTT实验表明,大豆苷元的IC_(50) 30～100μmol·L~(-1),由此选定用于后续实验的药物浓度为0.3～10μmol·L~(-1)。膜片钳实验结果表明,当给予终浓度为0.3、1、3、10μmol·L~(-1)大豆苷元后,药物对I_(Na)呈浓度依赖性抑制现象;大豆苷元0.3μmol·L~(-1)时对I_(Na)作用的时间过程也具有一定影响,随时间推移缓慢减小;1、3、10μmol·L~(-1)大豆苷元使I-U曲线上移;在此同等条件下,激活曲线向去极化方向移动、稳态失活曲线向超极化方向移动和失活后恢复曲线的τ值延长。结论大豆苷元对大鼠心室肌Na~+通道有明显的抑制作用,这可能是其抗心律失常的机制之一。     

常咯啉对豚鼠和家兔单个心肌细胞钾电流的影响(英文)

目的:研究常咯啉是否对心肌细胞的钾电流有影响作用。方法:采用高阻抗密封膜片箝全细胞技术,记录分离的豚鼠和家兔心肌单个细胞的钾电流。结果:在临床用量常咯啉50μmol·L~(-1)抑制家兔心房肌细胞的瞬间外向钾电流(I_(TO))17.7％±2.4％(n=8)。但并不影响电压依赖性通道。同一剂量的常咯啉对单个家兔心室肌细胞的内向整流钾电流(I_(Kl))和单个豚鼠心室肌细胞的延迟整流钾电流(I_K)并不产生任何作用。结论:提示常咯啉具有阻制(I_(TO))的作用,而对(I_K)和(I_(Kl))无任何作用。     

六肽FRCRSFa对大鼠心室肌Na~ /Ca~(2 )交换的抑制(英文)

目的:研究六肽FRCRSFa对大鼠心室肌细胞Na~ /Ca~(2 )交换的作用及其特异性.方法:用膜片箝全细胞记录法测定Na~ /Ca~(2 )交换电流(I_(Na Ca~(2 ))及其它离子通道电流.结果:六肽FRCRSFa对大鼠心室肌细胞Na~ /Ca~(2 )交换呈剂量依赖性抑制,内向和外向I_(Na~ Ca~(2 ))的IC_(50)分别是2μmol/L和4μmol/L.FRCRSFa 5μmol/L对L型钙电流,门控钠电流、瞬时外向钾电流和内向整流钾电流均无显著抑制作用.结论:FRCRSFa是一个对Na~ /Ca~(2 )交换选择性较高的抑制剂,对研究心肌细胞Na~ /Ca~(2 )交换具有较高价值.     

1—（2，6—二甲基苯氧基）—2—（3，4—二甲氧基苯乙氨基）丙烷盐酸盐抑制豚鼠心室肌细胞内向整流和延迟整流钾电流

目的:研究1-(2,6-二甲基苯氧基)-2-(3,4-二甲氧基苯乙氨基)丙烷盐酸盐(DDPH)对心室肌细胞动作电位(AP)、内向整流钾通道电流(I_(K1))及延迟整流钾通道电流(I_K)的影响。方法:全细胞膜片箝技术。结果:DDPH 10,100μmol·L~(-1)使豚鼠心室肌细胞AP时程APD_(50)明显缩短;但DDPH(>1μmol·L~(-1))延长APD_(90)。DDPH浓度依赖性地抑制I_K尾电流(I_(K·tail)),EC_(50)为13.3(11.6.6-16.7)μmol·L~(-1)。DDPH(>1.0μmol·L~(-1))明显抑制I_(Kl);同时,DDPH使I_(Kl)翻转电位向正电位方向移动。结论:DDPH对豚鼠心室肌细胞I_(Kl)和I_K具有明显的抑制作用。     

蝙蝠葛碱对豚鼠心室肌细胞钾电流的阻断作用(英文)

目的:研究蝙蝠葛碱对豚鼠心室肌细胞快激活(I_(Kr))和慢激活(I_(Ks))延迟整流钾电流及内向整流钾电流(I_(K1))的作用。方法:酶解法制备单个心室肌细胞。电压箝制方式下全细胞记录豚鼠单个心室肌细胞钾通道电流。结果:蝙蝠葛碱1-100μmol·L~(-1)浓度依赖性阻断I_(Ks),I_(Ks-tail)[IC_(50)=33(95 ％可信限:24-46)μmol·L~(-1)]及I_(Kr),I_(Kr-tail)[IC_(50))=16 (95％可信限:13-22)μmol·L~(-1)]。对I_(Ks-tail),I_(Kr-tail)的去激活过程无明显影响,给药前的时间常数分别为(92±18)ms和(140±38)ms,给药后分别为(84±16)ms和(130±26)ms(P>0.05)。蝙蝠葛碱对I_(Ks)的抑制作用具有电压依赖性。 蝙蝠葛碱20μmol·L~(-1)对I_(K1)的内向部分具有阻断作用。结论:蝙蝠葛碱对I_(Kr)和I_(Ks)具有阻断作用,但不影响此两种成分的去激活过程. 蝙蝠葛碱同时具有阻断I_(K1)的作用。     

苄普地尔抑制大鼠海马CA1区锥体细胞钠电流(英文)

目的:研究苄普地尔对大鼠海马CA1区锥体细胞钠电流的影响。方法:膜片箝全细胞记录技术。结果:苄普地尔显著降低大鼠海马CA1区锥体细胞钠电流,作用呈时间及浓度依赖关系。苄普地尔10μmol·L~(-1)的半阻断时间约为10min。IC_(50)为2.6(2.3-2.9)μmol·L~(-1)。苄普地尔10μmol·L~(-1)右移最大电流的激活电位10mV,左移半失活膜电位18mV,表明其电压依赖地影响钠通道的激活和失活过程。结论:苄普地尔阻断大鼠海马CA1区锥体细胞钠电流,可能是其抗脑缺血机制之一。     

卡维地洛对大鼠心室肌细胞钠通道的影响

目的研究卡维地洛对大鼠心室肌细胞膜钠通道的影响,在离子通道水平探讨卡维地洛的抗心律失常作用机制。方法用急性酶解法获得单个大鼠心室肌细胞,标准的全细胞膜片钳技术记录钠通道电流。结果①卡维地洛呈浓度依赖性抑制钠通道电流,IC50=(6.35±0.40)μmol·L-1。②10μmol·L-1卡维地洛能使心肌细胞钠通道电流-电压关系曲线明显上移,峰电流从(17.31±1.68)pA/pF减少至(6.58±1.35)pA/pF(n=8,P<0.05),激活电位、峰电位和翻转电位无明显改变。③卡维地洛能使钠通道电流失活曲线明显左移。④卡维地洛对钠通道电流的激活和复活曲线无明显影响。⑤卡维地洛呈频率依赖性地抑制钠通道电流。⑥1μmol·L-1卡维地洛能明显阻断10μmol·L-1异丙肾上腺素增加钠通道电流效应。结论卡维地洛能够抑制心肌细胞钠通道电流,呈浓度依赖性和频率依赖性。     

Interaction of hydrogen sulfide with ion channels

1. Hydrogen sulfide (H₂S) is a signalling gasotransmitter. It targets different ion channels and receptors, and fulfils its various roles in modulating the functions of different systems. However, the interaction of H₂S with different types of ion channels and underlying molecular mechanisms has not been reviewed systematically. 2. H₂S is the first identified endogenous gaseous opener of ATP‐sensitive K⁺ channels in vascular smooth muscle cells. Through the activation of ATP‐sensitive K⁺ channels, H₂S lowers blood pressure, protects the heart from ischemia and reperfusion injury, inhibits insulin secretion in pancreatic β cells, and exerts anti‐inflammatory, anti‐nociceptive and anti‐apoptotic effects. 3. H₂S inhibited L‐type Ca²⁺ channels in cardiomyocytes but stimulated the same channels in neurons, thus regulating intracellular Ca²⁺ levels. H₂S activated small and medium conductance K_Ca channels but its effect on BK_Ca channels has not been consistent. 4. H₂S‐induced hyperalgesia and pro‐nociception seems to be related to the sensitization of both T‐type Ca²⁺ channels and TRPV₁ channels. The activation of TRPV₁ and TRPA₁ by H₂S is believed to result in contraction of nonvascular smooth muscles and increased colonic mucosal Cl^? secretion. 5. The activation of Cl^? channel by H₂S has been shown as a protective mechanism for neurons from oxytosis. H₂S also potentiates N‐methyl‐d ‐aspartic acid receptor‐mediated currents that are involved in regulating synaptic plasticity for learning and memory. 6. Given the important modulatory effects of H₂S on different ion channels, many cellular functions and disease conditions related to homeostatic control of ion fluxes across cell membrane should be re‐evaluated.     

The real life of voltage-gated K channels: more than model behaviour

The past ten years have provided an embarrassment of riches for those interested in cloned voltage-gated K⁺ (Kv) channels. Details of their physiology and pharmacology in expression systems, and their precise cellular location abound, making them excellent targets for pharmacologists. However, there is still a considerable and important gap in our knowledge between the behaviour of expressed Kv channels and K⁺ currents in vivo. In this review Brian Robertson focuses on a few of the recent developments in the field of Kv channels, namely modulation of their behaviour by accessory subunits, their control, and localization of identified Kv subunits.     

An assessment of the present and future roles of non-ligand gated ion channel modulators as CNS therapeutics

Few approved drugs have, as their primary known mechanism of action, modulation of non-ligand gated ion channels. However, these proteins are important regulators of neuronal function through their control of sodium, potassium, calcium and chloride flux, and are ideal candidates as drug discovery targets. Recent progress in the molecular biology and pharmacology of ion channels suggests that many will be associated with specific pharmacological profiles that will include both activators and inhibitors. Ion channels, through their regulation by G-proteins, are a major component of the final common pathway of many drugs acting at classical neuronal receptors. Thus, targeting of the ion channels themselves may confer different profiles of efficacy and specificity to drug action in the brain and spinal cord. Three areas for drug discovery are profiled that the authors consider prime targets for ion channel based therapies, anticonvulsant drugs, cognition enhancing drugs and drugs for improving neurone survival following ischaemia.     

罗哌卡因对豚鼠心室肌细胞钠电流、钙电流和钾电流的影响

目的:研究罗哌卡因(Rop)对豚鼠心室肌细胞钠电流(Ⅰ_(Na))、L-型钙电流(Ⅰ_(Ca-L)、内向整流钾电流(Ⅰ_(Kl)及延迟整流钾电流(I_K)的影响.方法:全细胞膜片箝技术.结果:罗哌卡因10,50与100μmol/L使Ⅰ_(Na)的峰电流分别减小8.3％、33.3 ％和62.5％(P<0.01),使失活时间常数分别延长8.2％、24.7％和64.1％(P<0.05);罗哌卡因50与100μmol/L使Ⅰ_(Ca-L)的峰电流分别减小7.6％和22.5％(P<0.05),使慢失活时间常数分别延长15.5％和33.0％(P<0.01);罗哌卡因50与100μmol/L对Ⅰ_(Kl)和Ⅰ_K的峰电流无明显影响.结论:罗哌卡因抑制Ⅰ_(Na)和Ⅰ_(Ca-L),可能与其心脏毒性作用有关.     

Pharmacological activation and inhibition of Slack (Slo2.2) channels

The Slack (Sequence like a calcium-activated K channel) (Slo2.2) gene is abundantly expressed in the mammalian brain and encodes a sodium-activated K+ (KNa) channel. Although the specific roles of Slack channel subunits in neurons remain to be identified, they may play a role in the adaptation of firing rate and in protection against ischemic injury. In the present study, we have generated a stable cell line expressing the Slack channel, and have analyzed the pharmacological properties of these channels in these cells and in Xenopus oocytes. Two known blockers of KNa channels, bepridil and quinidine, inhibited Slack currents in a concentration-dependent manner and decreased channel activity in excised membrane patches. The inhibition by bepridil was potent, with an IC50 of 1.0 microM for inhibition of Slack currents in HEK cells. In contrast, bithionol was found to be a robust activator of Slack currents. When applied to the extracellular face of excised patches, bithionol rapidly induced a reversible increase in channel opening, suggesting that it acts on Slack channels relatively directly. These data establish an important early characterization of agents that modulate Slack channels, a process essential for the experimental manipulation of Slack currents in neurons.     

高血压发展过程中脑血管平滑肌细胞离子通道的变化

脑血管重构是高血压发展过程中最重要的病理生理改变,由此引起的脑卒中更日益危害人类的健康。在高血压发展过程中,脑血管平滑肌细胞上分布的多种离子通道,如钾钙、氯等均发生变化,导致细胞内离子浓度异常,在脑血管重构的发生发展过程中发挥了重要作用。     

Pharmacological modulation of voltage-gated potassium channels as a therapeutic strategy

Importance of the field: The human genome encodes at least 40 distinct voltage-gated potassium channel subtypes, which vary in regional expression, pharmacological and biophysical properties. Voltage-dependent potassium (Kv) channels help orchestrate many of the physiological and pathophysiological processes that promote and sometimes hinder the healthy functioning of our bodies.

Areas covered in this review: This review summarizes patent and scientific literature reports from the past decade highlighting the opportunities that Kv channels offer for the development of new therapeutic interventions for a wide variety of disorders.

What the reader will gain: The reader will gain an insight from an analysis of the associations of different Kv family members with disease processes, summary and evaluation of the development of therapeutically relevant pharmacological modulators of these channels, particularly focusing on proprietary agents being developed.

Take home message: Development of new drugs that target Kv channels continue to be of great interest but is proving to be challenging. Nevertheless, opportunities for Kv channel modulators to have an impact on a wide range of disorders in the future remain an exciting prospect.     

Functional and pharmacological properties of human and rat NaV1.8 channels

The aim of this work is to characterise the functional properties of human and rat Na_V1.8 channels and to investigate the action of anti-nociceptive agents. Na_V1.8 α-subunits were expressed in mammalian sensory neuron-derived ND7/23 cells, and sodium currents were recorded using whole-cell patch clamp. The current-voltage curves for activation were similar for human and rat Na_V1.8 channels. However, for inactivation, human Na_V1.8 showed more hyperpolarised voltage-dependence than for the rat channel, faster development of inactivation, slower recovery from the fast component of inactivation, and faster recovery from the slow component. Thus, this would imply that the human channel is more inactivated at normal resting potentials. Compounds 227c89, A-803467, V102862, ralfinamide and tetracaine all showed greater affinity for the inactivated state than for the resting state. Compounds A-803467 and V102862 were the most potent, and A-803467 showed greater inactivated state affinity for human than for rat channels. Surprisingly, during recovery from inactivation, an increase in current was observed for V102862 and A-803467, probably due to disinhibition of resting block. Rather than the use-dependent inhibition normally seen with inactivated state blockers, for A-803467 this disinhibition led to an increase in current during repetitive stimulation, while V102862 showed less inhibition than otherwise expected at lower frequencies. Thus the data supports the suggestion that, while both V102862 and A-803467 are potent inhibitors of Na_V1.8, the compound V102862, rather than A-803467, may be useful as an analgesic where physiological firing frequencies are higher.     

Arachidonic acid and ion channels: an update

Arachidonic acid (AA), a polyunsaturated fatty acid with four double bonds, has multiple actions on living cells. Many of these effects are mediated by an action of AA or its metabolites on ion channels. During the last 10 years, new types of ion channels, transient receptor potential (TRP) channels, store-operated calcium entry (SOCE) channels and non-SOCE channels have been studied. This review summarizes our current knowledge about the effects of AA on TRP and non-SOCE channels as well as classical ion channels. It aims to distinguish between effects of AA itself and effects of AA metabolites. Lipid mediators are of clinical interest because some of them (for example, leukotrienes) play a role in various diseases, others (such as prostaglandins) are targets for pharmacological therapeutic intervention.