ELECTROPHYSIOLOGY OF MAMMALIAN INFERIOR OLIVARY NEURONS INVITRO - DIFFERENT TYPES OF VOLTAGE-DEPENDENT IONIC CONDUCTANCES
ELECTROPHYSIOLOGY OF MAMMALIAN INFERIOR OLIVARY NEURONS INVITRO - DIFFERENT TYPES OF VOLTAGE-DEPENDENT IONIC CONDUCTANCES
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DOI：
10.1113/jphysiol.1981.sp013763
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发表时间：
1981-01-01
影响因子：
5.5
通讯作者：
YAROM, Y
中科院分区：
文献类型：
--
作者：
LLINAS, R;YAROM, Y
在体外脑干切片制备中，研究了豚鼠下橄榄核(IO)细胞的电生理特性。对该核团185个神经元的细胞内记录表明，逆行、顺行或直接刺激产生的动作电位由快速峰电位和后除极电位(ADP)组成。ADP的波幅为49.+-。8 mV(平均值+-SD)和随去极化程度在大范围内变化的持续时间。该ADP之后是幅度为12.+-的后超极化电位(AHP)。3 mV(平均值+-。SD)，持续时间长达250毫秒。AHP显示了一个反弹的去极化波。用位于IO核附近的双极电极刺激橄榄核周围可以获得突触激活。这些电位是去极化和超极化突触事件的混合体，可被直接膜极化逆转。在浴液中加入河豚毒素(TTX)，或去除细胞外钠，取消快速初始动作电位，但不改变ADP或AHP。用钴、锰、镉或D600[甲氧基维拉帕米]阻断钙电导，或用镁取代钙，取消ADP-AHP序列。神经元的超极化揭示了低阈值的钙电导，这种电导在静止时是失活的，具有与ADP相似的药理学特性。这一低门槛峰值在AHP之后的反弹潜力中发挥着核心作用。同时刺穿IO神经元对显示神经元之间存在电紧张性耦合，尤其是在内侧副橄榄核。
The electrophysiological properties of guinea-pig inferior olivary (IO) cells were studied in an in vitro brain stem slice preparation. Intracellular recordings from 185 neurons in this nucleus reveal that antidromic, orthodromic or direct stimulation generates action potentials consisting of a fast spike followed by an after-depolarizing potential (ADP). The ADP had an amplitude of 49 .+-. 8 mV (mean .+-. SD) and a duration which varied over a wide range with the level of depolarization. This ADP is followed by an after-hyperpolarizing potential (AHP) having an amplitude of 12 .+-. 3 mV (mean .+-. SD) from rest and lasting up to 250 ms. The AHP shows a rebound depolarization wave. Synaptic activation may be obtained by peri-olivary stimulation with a bipolar electrode located in the immediate vicinity of the IO nucleus. These potentials are a mixture of depolarizing and hyperpolarizing synaptic events which can be reversed by direct membrane polarization. Addition of tetrodotoxin (TTX) to the bath, or removal of extracellular Na, abolishes the fast initial action potential but does not modify the ADP or the AHP. Blockage of Ca conductance by Co, Mn, Cd or D600 [methoxyverapamil], or replacement of Ca by Mg, abolishes the ADP-AHP sequence. Hyperpolarization of the neuron uncovers a low-threshold Ca conductance, which is inactivated at rest and has similar pharmacological properties to the ADP. This low-threshold spike plays a central role in the rebound potential following the AHP. Simultaneous impalement of IO neuron pairs demonstrated the presence of electrotonic coupling between neurons, which is especially prominent in the medial accessory olive.