Tian G F, Peever J H, Duffin J
Department of Physiology, University of Toronto, Ontario, Canada.
Exp Brain Res. 1999 Jan;124(2):173-80. doi: 10.1007/s002210050612.
Extracellularly recorded action potentials from 49 Bötzinger-complex, bulbospinal expiratory neurones were used as triggers to compute 162 spike-triggered averages (STAs) of intracellular potentials recorded from 167 respiratory neurones in the ventral respiratory group (VRG) near the obex in 15 vagotomized, paralysed, ventilated and decerebrated rats. All of the Bötzinger-complex expiratory neurones were antidromically activated from the ipsilateral border between the C2/C3 segments of the spinal cord and discharged only during the late part of expiration with an augmenting pattern. We found evidence for monosynaptic inhibitory post-synaptic potentials (IPSPs) in 74 (approximately 44%) of the STAs computed using 34 (approximately 69%) of the trigger neurones. For vagal motoneurones, IPSPs were found in 24 of the 53 STAs of expiratory motoneurones, but in none of the 12 STAs of inspiratory motoneurones. For inspiratory neurones, IPSPs were found in 23 of the 33 STAs of bulbospinal neurones and in 6 of the 26 STAs of not antidromically activated (NAA) neurones. For expiratory neurones, IPSPs were found in one of the two STAs of bulbospinal neurones and in 20 of the 36 STAs of NAA neurones. We conclude that Bötzinger-complex, bulbospinal expiratory neurones monosynaptically inhibit bulbospinal inspiratory neurones, expiratory vagal motoneurones and other unidentified inspiratory and expiratory neurones in the VRG of rats during the late part of expiration.
在15只经迷走神经切断、麻痹、通气和去大脑的大鼠中，从延髓闩部附近腹侧呼吸组（VRG）的167个呼吸神经元记录细胞内电位，以49个来自包钦格复合体的延髓脊髓呼气神经元的细胞外记录动作电位作为触发信号，计算出162个锋电位触发平均值（STA）。所有来自包钦格复合体的呼气神经元均能被来自脊髓C2/C3节段同侧边界的逆向激活，且仅在呼气后期以增强模式放电。我们发现，在使用34个（约69%）触发神经元计算出的74个（约44%）STA中，存在单突触抑制性突触后电位（IPSP）。对于迷走运动神经元，在呼气运动神经元的53个STA中的24个中发现了IPSP，但在吸气运动神经元的12个STA中均未发现。对于吸气神经元，在延髓脊髓神经元的33个STA中的23个以及未被逆向激活（NAA）神经元的26个STA中的6个中发现了IPSP。对于呼气神经元，在延髓脊髓神经元的2个STA中的1个以及NAA神经元的36个STA中的20个中发现了IPSP。我们得出结论，在呼气后期，来自包钦格复合体的延髓脊髓呼气神经元对大鼠VRG中的延髓脊髓吸气神经元、呼气迷走运动神经元以及其他未明确的吸气和呼气神经元具有单突触抑制作用。
