Sah P, Isaacson J S
Discipline of Physiology, Faculty of Medicine and Health Sciences, University of Newcastle, New South Wales, Australia.
Neuron. 1995 Aug;15(2):435-41. doi: 10.1016/0896-6273(95)90047-0.
The slow afterhyperpolarization in hippocampal pyramidal neurons is mediated by a calcium-activated potassium current (IAHP) and is a target for variety of different neurotransmitters. The characteristics of the channels underlying IAHP and how they are modulated by neurotransmitters are, however, unknown. In this study, we have examined the properties of the channels underlying IAHP using fluctuation analysis of the macroscopic current. Our results indicate that this channel has a unitary conductance of 2-5 pS and a mean open time of about 2 ms. When the peak amplitude of IAHP was maximal, these channels have an open probability of 0.4. Noradrenaline and carbachol reduced IAHP amplitude by lowering open channel probability. These result indicate that a novel calcium-activated potassium channel underlies IAHP. This channel is modulated in a similar fashion by two different transmitter systems that utilize distinct protein kinases.
海马锥体神经元中的缓慢超极化后电位由钙激活钾电流（IAHP）介导，并且是多种不同神经递质的作用靶点。然而，IAHP所依赖通道的特性以及它们如何被神经递质调节尚不清楚。在本研究中，我们使用宏观电流的波动分析来研究IAHP所依赖通道的特性。我们的结果表明，该通道的单位电导为2 - 5 pS，平均开放时间约为2毫秒。当IAHP的峰值幅度最大时，这些通道的开放概率为0.4。去甲肾上腺素和卡巴胆碱通过降低开放通道概率来降低IAHP幅度。这些结果表明，一种新型的钙激活钾通道是IAHP的基础。该通道被利用不同蛋白激酶的两种不同递质系统以类似方式调节。
