Distinct contributions of small and large conductance Ca2+-activated K+ channels to rat Purkinje neuron function
Distinct contributions of small and large conductance Ca2+-activated K+ channels to rat Purkinje neuron function
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DOI：
10.1113/jphysiol.2002.027854
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发表时间：
2003-04-01
影响因子：
5.5
通讯作者：
Reinhart, PH
中科院分区：
文献类型：
--
作者：
Edgerton, JR;Reinhart, PH
小脑对行为的许多方面都很重要，从保持姿势和以目标为导向的伸展运动到为任务计时和某些形式的学习。在每种情况下，流经小脑的信息都通过浦肯野神经元，这些神经元接受来自两个主要小脑传入的输入，并产生连续的动作电位流，构成从小脑皮质到深部核团的唯一输出。在体内观察到的浦肯野神经元的紧张性放电行为在脑片中保持，即使突触输入被阻断，这表明浦肯野神经元的活动在很大程度上依赖于内在电导。以前的研究表明，钙电流和钙激活的钾通道(K-Ca通道)之间的相互作用对浦肯野细胞的活动很重要，但存在多少种不同的KCA通道类型，以及每种通道类型对细胞行为的贡献尚不清楚。为了更好地了解控制这些神经元行为的离子机制，我们观察了不同的钙通道和钾-钙通道拮抗剂对大鼠小脑急性脑片浦肯野神经元的影响。我们的数据表明，钙离子通过P型电压门控钙离子通道同时激活小电导(SK)和大电导(BK)钾-钙通道。SK通道在设定固有放电频率中起作用，而BK通道调节动作电位的形状，并可能参与独特的爬行纤维反应。
The cerebellum is important for many aspects of behaviour, from posture maintenance and goal-oriented reaching movements to timing tasks and certain forms of learning. In every case, information flowing through the cerebellum passes through Purkinje neurons, which receive input from the two primary cerebellar afferents and generate continuous streams of action potentials that constitute the sole output from the cerebellar cortex to the deep nuclei. The tonic firing behaviour observed in Purkinje neurons in vivo is maintained in brain slices even when synaptic inputs are blocked, suggesting that Purkinje neuron activity relies to a significant extent on intrinsic conductances. Previous research has suggested that the interplay between Ca2+ currents and Ca2+-activated K+ channels (K-Ca channels) is important for Purkinje cell activity, but how many different KCa channel types are present and what each channel type contributes to cell behaviour remains unclear. In order to better understand the ionic mechanisms that control the behaviour of these neurons, we investigated the effects of different Ca2+ channel and K-Ca channel antagonists on Purkinje neurons in acute slices of rat cerebellum. Our data show that Ca2+ entering through P-type voltage-gated Ca2+ channels activates both small-conductance (SK) and large-conductance (BK) K-Ca channels. SK channels play a role in setting the intrinsic firing frequency, while BK channels regulate action potential shape and may contribute to the unique climbing fibre response.