Electrophysiological properties of neurons within the nucleus ambiguus of adult guinea pigs.
Electrophysiological properties of neurons within the nucleus ambiguus of adult guinea pigs.
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成年豚鼠疑核内神经元的电生理特性。
DOI：
10.1152/jn.1991.66.3.744
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发表时间：
1991
影响因子：
2.5
通讯作者：
Getting,PA
中科院分区：
文献类型：
--
作者：
Johnson,SM;Getting,PA
1.本研究的目的是确定疑核(NA)内神经元的电生理特性，该区域包含腹侧呼吸群。用体外脑干切片的方法，该区域神经元(简称NA神经元，n=235)的细胞内记录显示出以下特性：抑制后反弹(PIR)、延迟兴奋(DE)、适应和强直后超极化(PTH)。根据PIR和DE的表达将NA神经元分为三组：PIR细胞(58%)、DE细胞(31%)和无细胞(10%)。无细胞既不表达PIR也不表达DE，无细胞同时表达PIR和DE。2.PIR是一种瞬时去极化，当细胞从超极化状态释放时，它会产生单个动作电位或一连串动作电位。在河豚毒素(TTX)存在下，PIR的最大值为7-12 mV。在电压钳制条件下，超极化电压阶跃在超极化过程中产生小的内向电流，在超极化释放时产生小的内向尾流。这些介导PIR的电流很可能是由Q电流引起的，因为它们被细胞外的铯阻断，对Ba2+不敏感。3.去极化是细胞在施加去极化电流前超极化时，动作电位放电起始时间的延迟。当细胞超极化至-90 mV，持续时间大于或等于300ms时，最大延迟时间为150~450ms。根据电流的激活和失活特性，推测DE下的瞬时外向电流为A电流，并被4-氨基吡啶(4-AP)消除。4.对2.0%的S施加去极化电流，并测量诱发动作电位的频率，观察其适应情况。尽管在适应程度上有很大的变异性，但PIR细胞比DE和非细胞表现出更少的适应。近四分之三的NA神经元适应迅速(即50%的适应在不到200ms内)，但PIR细胞的适应速度往往快于DE和非细胞。一系列动作电位后的甲状旁腺激素相对较少，在DE细胞(43%)和非细胞(33%)中的发生率高于PIR细胞(13%)。PTH的震级高达18 mV，时间常数反映了一个分量(1·7+/-1·4 S，均值+/-SD)或两个分量(0·28+/-0·13和4·1+/-2·2 S)的存在。
1. The purpose of this study was to determine the electrophysiological properties of neurons within the region of the nucleus ambiguus (NA), an area that contains the ventral respiratory group. By the use of an in vitro brain stem slice preparation, intracellular recordings from neurons in this region (to be referred to as NA neurons, n = 235) revealed the following properties: postinhibitory rebound (PIR), delayed excitation (DE), adaptation, and posttetanic hyperpolarization (PTH). NA neurons were separated into three groups on the basis of their expression of PIR and DE: PIR cells (58%), DE cells (31%), and Non cells (10%). Non cells expressed neither PIR nor DE and no cells expressed both PIR and DE. 2. PIR was a transient depolarization that produced a single action potential or a burst of action potentials when the cell was released from hyperpolarization. In the presence of tetrodotoxin (TTX), the maximum magnitude of PIR was 7-12 mV. Under voltage-clamp conditions, hyperpolarizing voltage steps elicited a small inward current during the hyperpolarization and a small inward tail current on release from hyperpolarization. These currents, which mediate PIR, were most likely due to Q-current because they were blocked with extracellular cesium and were insensitive to barium. 3. DE was a delay in the onset of action potential firing when cells were hyperpolarized before application of depolarizing current. When cells were hyperpolarized to -90 mV for greater than or equal to 300 ms, maximum delays ranged from 150 to 450 ms. The transient outward current underlying DE was presumed to be A-current because of the current's activation and inactivation characteristics and its elimination by 4-aminopyridine (4-AP). 4. Adaptation was examined by applying depolarizing current for 2.0 s and measuring the frequency of evoked action potentials. Although there was a large degree of variability in the degree of adaptation, PIR cells tended to express less adaptation than DE and Non cells. Nearly three-fourths of all NA neurons adapted rapidly (i.e., 50% adaptation in less than 200 ms), but PIR cells tended to adapt faster than DE and Non cells. PTH after a train of action potentials was relatively rare and occurred more often in DE cells (43%) and Non cells (33%) than in PIR cells (13%). PTH had a magnitude of up to 18 mV and time constants that reflected the presence of one (1.7 +/- 1.4 s, mean +/- SD) or two components (0.28 +/- 0.13 and 4.1 +/- 2.2 s).(ABSTRACT TRUNCATED AT 400 WORDS)