Ezure K, Manabe M
Department of Neurobiology, Tokyo Metropolitan-Institute for Neurosciences, Japan.
Exp Brain Res. 1988;72(1):159-66. doi: 10.1007/BF00248511.
In Nembutal-anesthetized, immobilized and artificially ventilated cats, decrementing expiratory (E-DEC) neurons which were excited by lung inflation were isolated in the vicinity of the Bötzinger complex. Then intracellular recordings were made from the respiratory neurons in the contralateral ventral respiratory group (VRG). The intracellular membrane potentials were averaged using extracellular spikes of the E-DEC neurons as triggers (spike-triggered averaging method). Hyperpolarizing potentials locked to the triggering spikes were obtained and they were shown to be unitary IPSPs since their polarity was reversed when averaged during passage of hyperpolarizing current. The latencies of antidromic activation of the E-DEC neurons from the area of intracellular recordings were shorter by about 0.2 ms than those of unitary IPSPs. This showed that the connections were monosynaptic. A total of 47 pairs were analyzed and unitary IPSPs were found in 12 pairs. The E-DEC neurons inhibited both inspiratory and expiratory neurons, including bulbospinal inspiratory neurons, propriobulbar inspiratory neurons, and vagal motoneurons with expiratory activity. These inhibitory E-DEC neurons, receiving excitatory inputs from the stretch receptors of the lungs, presumably intervene in reflex loops such as the Hering-Breuer reflex and may make some contribution to normal breathing.
在戊巴比妥麻醉、麻痹并进行人工通气的猫身上，在布氏复合体附近分离出了因肺扩张而兴奋的递减呼气（E-DEC）神经元。然后从对侧腹侧呼吸组（VRG）的呼吸神经元进行细胞内记录。以E-DEC神经元的细胞外锋电位作为触发信号（锋电位触发平均法），对细胞内膜电位进行平均。获得了与触发锋电位锁定的超极化电位，并且由于在通过超极化电流时进行平均时其极性发生反转，表明它们是单一抑制性突触后电位（IPSPs）。从细胞内记录区域对E-DEC神经元进行逆向激活的潜伏期比单一IPSPs的潜伏期短约0.2毫秒。这表明连接是单突触的。总共分析了47对，在12对中发现了单一IPSPs。E-DEC神经元抑制吸气和呼气神经元，包括延髓脊髓吸气神经元、脑桥固有吸气神经元以及具有呼气活动的迷走运动神经元。这些抑制性E-DEC神经元从肺的牵张感受器接受兴奋性输入，推测参与诸如黑林-布雷尔反射等反射回路，可能对正常呼吸有一定作用。
