Conductances and selective permeability of connexin43 gap junction channels examined in neonatal rat heart cells.
Conductances and selective permeability of connexin43 gap junction channels examined in neonatal rat heart cells.
复制标题
在新生大鼠心脏细胞中检查 connexin43 间隙连接通道的电导和选择性通透性。
DOI：
10.1161/01.res.80.5.708
复制
发表时间：
1997
影响因子：
20.1
通讯作者：
R. Weingart
中科院分区：
文献类型：
--
作者：
V. Valiunas;F. Bukauskas;R. Weingart
采用双电压钳方法，对新生大鼠心肌细胞缝隙连接通道的传导特性进行了研究。对三种类型（组）的制剂进行实验：（1）诱导的细胞对，（2）具有很少间隙连接通道的预形成的细胞对（1至3个通道），以及（3）具有许多通道的预制电池对在用解偶联剂如SKF-525 A（75 μ mol/L）、庚醇（3 mmol/L）和花生四烯酸（100 μ mol/L）处理后，可以观察到（100至200个通道）。在第1组中，新形成的通道的第一次开放是缓慢的（20至65毫秒），并发生在物理细胞接触后7至25分钟。通道插入速率为1.3通道/min。与结电压梯度（Vj）相关，通道显示多个电导、主开放状态[gamma（j）（主状态）]、几个子状态[gamma（j）（子状态）]和残留状态[gamma（j）（残留状态）]。在极少数情况下，通道完全关闭。在第2组和第3组中观察到相同的现象。γ（j）（残留状态）的存在为具有许多间隙连接通道的细胞对中在大Vj值下的连接电流（Ij）的不完全失活提供了解释。从第1、2和3组获得的伽马（j）（主药状态）和伽马（j）（残留状态）值结果相当，因此合并。数据与高斯分布的拟合揭示了两个电导的窄单峰。γ（j）值取决于移液器溶液的组成。解决办法如下：（1）KCl溶液，γ（j）（主态）=96 pS，γ（j）（残留态）=23 pS;（2）Cs+天冬氨酸溶液，γ（j）（主态）=61 pS，γ（j）（残留态）=12 pS;（3）四乙基铵+天冬氨酸溶液，γ（j）（主态）=19 pS，γ（j）（残留态）=3 pS。相应的伽马（j）（主状态）与伽马（j）（残留状态）的比率为4.2、5.1和6.3。这表明残留态比主态更有效地限制离子渗透。Ij在开放状态（主开放状态、子状态和残留状态）之间的转换是快速的（<2 ms），而涉及闭合状态和开放状态的转换是缓慢的（15至65 ms）。这意味着存在两种门控机制。剩余态可被视为由Vj控制的电门控的基态;闭合态可被视为化学门控的基态。
Myocytes from neonatal rat hearts were used to assess the conductive properties of gap junction channels by means of the dual voltage-clamp method. The experiments were carried out on three types (groups) of preparations: (1) induced cell pairs, (2) preformed cell pairs with few gap junction channels (1 to 3 channels), and (3) preformed cell pairs with many channels (100 to 200 channels) after treatment with uncoupling agents such as SKF-525A (75 micromol/L), heptanol (3 mmol/L), and arachidonic acid (100 micromol/L). In group 1, the first opening of a newly formed channel was slow (20 to 65 ms) and occurred 7 to 25 minutes after physical cell contact. The rate of channel insertion was 1.3 channels/min. Associated with a junctional voltage gradient (Vj), the channels revealed multiple conductances, a main open state [gamma(j)(main state)], several substates [gamma(j)(substates)], and a residual state [gamma(j)(residual state)]. On rare occasions, the channels closed completely. The same phenomena were observed in groups 2 and 3. The existence of gamma(j)(residual state) provides an explanation for the incomplete inactivation of the junctional current (Ij) at large values of Vj in cell pairs with many gap junction channels. The values of gamma(j)(main state) and gamma(j)(residual state) gained from groups 1, 2, and 3 turned out to be comparable and hence were pooled. The fit of the data to a Gaussian distribution revealed a narrow single peak for both conductances. The values of gamma(j) were dependent on the composition of the pipette solution. Solutions were as follows: (1) KCl solution, gamma(j)(main state)=96 pS and gamma(j)(residual state)=23 pS; (2) Cs+ aspartate solution, gamma(j)(main state)=61 pS and gamma(j)(residual state)=12 pS; and (3) tetraethylammonium+ aspartate solution, gamma(j)(main state)=19 pS and gamma(j)(residual state)=3 pS. The respective gamma(j)(main state)-to-gamma(j)(residual state) ratios were 4.2, 5.1, and 6.3. This indicates that the residual state restricts ion permeation more efficiently than does the main state. Transitions of Ij between open states (main open state, substates, and residual state) were fast (<2 ms), and transitions involving the closed state and an open state were slow (15 to 65 ms). This implies the existence of two gating mechanisms. The residual state may be regarded as the ground state of electrical gating controlled by Vj; the closed state, as the ground state of chemical gating.
登录
查看更多内容
影响因子：
20.1
作者：
DARROW, BJ;LAING, JG;BEYER, EC
通讯作者：
BEYER, EC
通过跨接点电压对哺乳动物心脏间隙连接通道进行门控。
影响因子：
3.4
作者：
Wang,HZ;Li,J;Lemanski,LF;Veenstra,RD
通讯作者：
Veenstra,RD
影响因子：
20.1
作者：
KANTER, HL;LAING, JG;SAFFITZ, JE
通讯作者：
SAFFITZ, JE
成人心室肌细胞之间间隙连接的一些电学和药理学特性。
DOI：
10.1152/ajpcell.1985.249.5.c447
发表时间：
1985
期刊：
The American journal of physiology
影响因子：
--
作者：
White,RL;Spray,DC;CamposdeCarvalho,AC;Wittenberg,BA;Bennett,MV
通讯作者：
Bennett,MV
胚胎鸡心室细胞对间隙连接通道的电压依赖性门控。
DOI：
10.1152/ajpcell.1990.258.4.c662
发表时间：
1990
期刊：
The American journal of physiology
影响因子：
--
作者：
Veenstra,RD
通讯作者：
Veenstra,RD