Voltage-activated currents through calcium channels in normal bovine lactotrophs
Voltage-activated currents through calcium channels in normal bovine lactotrophs
复制标题
正常牛泌乳素细胞中通过钙通道的电压激活电流
DOI：
10.1016/0306-4522(87)90084-4
复制
发表时间：
1987
期刊：
影响因子：
3.3
通讯作者：
W. Mason
中科院分区：
文献类型：
--
作者：
P. Cobbett;C. Ingram;W. Mason
用膜片钳技术研究了免疫细胞化学鉴定的正常牛催乳素细胞的全细胞Ba2+电流特性。在电流钳模式下，记录到电流诱发和自发的Ba2+动作电位。与Na+动作电位相比，这些动作电位持续时间更长，失活频率更低。电压钳下，Ba2+电流的激活阈值约为−35 mV，峰值位于−15 mV~+20 mV。电流失活到依赖于电位的非零稳态水平表明存在一个快速失活分量和一个缓慢失活分量。这两个分量的区别还在于：(1)电流失活时间常数的电压依赖性，(2)峰值电流和稳态电流的差频相关失活，(3)电流存在两个半失活电位。对非失活分量的总体电流方差分析得出，在0 mV时，单通道幅度为0.19pA，斜率电导为3ps。电压激活的Ba2+电流噪声的涨落分析揭示了两个时间常数，一个与电压有关，另一个与电位无关。这两种电流对钙依赖激素分泌的作用尚不清楚。
The properties of whole cell Ba2+currents were studied in immunocytochemically identified, normal bovine lactotrophs using the patch clamp technique. In the current clamp mode, current-induced and spontaneous Ba2+action potentials were recorded. These were of longer duration and showed less inactivation with stimulation frequency when compared with Na+action potentials. Under voltage clamp, isolated Ba2+currents had an activation threshold of about −35 mV and peak value at −15 mV to + 20 mV. Inactivation of the current to a potential-dependent, non-zero steady-state level indicated the presence of one rapidly and one slowly inactivating component to the current. These two components were also distinguished by:(1) the voltage dependence of the inactivation time constant of the current, (2) the differential frequency-dependent inactivation of the peak and steady-state currents,(3) the presence of two half-inactivation potentials for the current.Analysis of the ensemble current variance of the non-inactivating component gave a single-channel amplitude of 0.19 pA at 0 mV and a slope conductance of 3 pS. Fluctuation analysis of the voltage-activated Ba2+current noise revealed two time constants, one which was voltage dependent and the other was independent of potential. The contribution of these two currents to Ca2+-dependent hormone secretion remains to be clarified.
促甲状腺激素释放激素 (TRH) 刺激 GH3 细胞中细胞质游离钙的双相升高。
影响因子：
4.8
作者：
Gershengorn,MC;Thaw,C
通讯作者：
Thaw,C