Synaptic events in ventral respiratory neurones during apnoea induced by laryngeal nerve stimulation in neonatal pig.
Synaptic events in ventral respiratory neurones during apnoea induced by laryngeal nerve stimulation in neonatal pig.
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新生猪喉神经刺激引起的呼吸暂停期间腹侧呼吸神经元的突触事件。
DOI：
10.1113/jphysiol.1991.sp018543
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
Lawson,EE
中科院分区：
文献类型：
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作者：
Czyzyk-Krzeska,MF;Lawson,EE
1.在戊巴比妥麻醉、切断迷走神经和人工通气的新生仔猪（n = 14，4 - 7日龄）中，在SLN诱导的腹侧呼吸组（VRG）呼吸神经元呼吸暂停期间，记录由上级喉神经（SLN）电刺激诱发的突触后电位。所有记录的吸气（n = 10）、吸气后（n = 10）和呼气（n = 20）神经元均具有膜电位的三相模式，并确定其向脊髓或颈迷走神经的投射。2.在SLN刺激诱导的长时间呼吸暂停期间，记录的每种神经元的膜电位轨迹保持在大致对应于呼气阶段I期间达到的膜电位的水平。在大多数呼吸相关神经元中诱发的复合突触后电位具有早期短持续和晚期长持续成分。3.在7个吸气神经元中，有4个的突触后电位得到了很好的证明，其特征是早期去极化，随后是持久的超极化。在其他三个吸气神经元，只有晚超极化。在晚期超极化的早期和晚期部分，通过细胞内氯化物注射实现了不同程度的晚期超极化的逆转。4.在16个神经元中研究了呼气神经元中诱发的突触后电位，并显示出两种模式：早期超极化，随后是长期超极化（n = 7，6个在脊髓刺激后未被逆向激活）或早期超极化，随后是晚期去极化（n = 9，8个投射到脊髓）。早期超极化很容易逆转氯化物注射。晚期超极化较难逆转，通常逆转不完全。5.在吸气后神经元中诱发的突触后电位显示出两个连续的去极化相的模式。6.本研究表明，在SLN刺激诱发的长时间呼吸暂停期间，每种VRG呼吸神经元都接收到来自喉传入神经反射的初始快速输入和代表整个呼吸网络参与反应的晚期输入的时间同步组合。
1. Postsynaptic potentials evoked by electrical stimulation of superior laryngeal nerve (SLN) were recorded during SLN‐induced apnoea from the respiratory neurones of the ventral respiratory group (VRG) in pentobarbitone‐anaesthetized, vagotomized and artificially ventilated newborn piglets (n = 14, 4‐7 days old). All recorded inspiratory (n = 10), post‐inspiratory (n = 10) and expiratory (n = 20) neurones had a triphasic pattern of membrane potential and were identified for their projections to the spinal cord or cervical vagus nerve. 2. During long‐lasting apnoea, induced by SLN stimulation, the membrane potential trajectory of each type of recorded neurone was held at the level corresponding approximately to the membrane potential reached during stage I of expiration. Compound postsynaptic potentials evoked in most respiratory‐related neurones had an early short‐lasting and a late long‐lasting component. 3. Postsynaptic potentials in four out of seven inspiratory neurones, in which postsynaptic potentials were well demonstrated, were characterized by an early depolarization followed by long‐lasting hyperpolarization. In three other inspiratory neurones only late hyperpolarization was present. The reversal of the late hyperpolarization by intracellular chloride injection was achieved to a different degree in the early and late portions of late hyperpolarization. 4. Postsynaptic potentials evoked in expiratory neurones were studied in sixteen neurones and displayed two patterns: early hyperpolarization followed by long‐lasting hyperpolarization (n = 7, six were not antidromically activated after spinal cord stimulation) or early hyperpolarization followed by late depolarization (n = 9, eight projected to the spinal cord). The early hyperpolarization was readily reversed by chloride injection. The late hyperpolarization was more difficult to reverse and usually the reversal was not completed. 5. Postsynaptic potentials evoked in post‐inspiratory neurones showed a pattern of two consecutive phases of depolarization. 6. The present study revealed that during long‐lasting apnoea evoked by SLN stimulation each category of VRG respiratory neurones received a temporally synchronized combination of an initial fast input derived reflexly from laryngeal afferents, and of late inputs representing involvement of the whole respiratory network in the response.