Richter D W, Camerer H, Meesmann M, Röhrig N
Pflugers Arch. 1979 Jul;380(3):245-57. doi: 10.1007/BF00582903.
In cats anaesthetized with pentobarbital, medullary respiratory neurones of both dorsal and ventral populations were recorded intracellularly with 1 mol.l-1 KCl-electrodes. The neurones were classified according to the projection of their axons to the spinal cord (bulbospinal neurones) or to the vagal nerves (vagal neurones). Those neurones which could not be activated antidromically (NAA-neurones) by either procedure were subdivided into (inspiratory) R beta-neurones, which were monosynaptically excited by lung stretch receptor afferents, and into inspiratory and expiratory NAA-neurones, which did not receive a direct synaptic input, from these afferents. All types of neurone investigated revealed postsynaptic activity during both inspiration and expiration. The periods when synaptic activity was minimal were the periods of transition between respiratory phases. The input resistance of most respiratory neurones varied in parallel with the respiratory cycle. A drastic fall of the input resistance during expiration was observed in R beta-neurones and in some inspiratory vagal neurones. This was not seen in inspiratory bulbospinal neurones. In stable intracellular recordings, periodic postsynaptic inhibition was demonstrated in 52 of 53 respiratory neurones by IPSP reversal following chloride injection. Maximal membrane potential then was generally reached during one of the periods of respiratory phase transition. Reasons for the failure of others to demonstrate these IPSPs are presented and discrepancies between other findings and these are discussed. It is concluded that reciprocal inhibition between bulbar respiratory neurones does exist and is a general phenomenon. It is argued that reciprocal inhibition is the fundamental mechanism underlying respiratory gating of afferent inputs. The probable existence of recurrent inhibition is inferred from the changes in the pattern of membrane depolarization during the active period of neurones.
在用戊巴比妥麻醉的猫身上，用1mol·L⁻¹氯化钾电极对背侧和腹侧的延髓呼吸神经元进行细胞内记录。根据轴突投射到脊髓（延髓脊髓神经元）或迷走神经（迷走神经元）对神经元进行分类。那些不能通过任何一种方法被逆向激活的神经元（非逆向激活神经元，NAA神经元）被细分为（吸气性）Rβ神经元，它们受到肺牵张感受器传入纤维的单突触兴奋，以及吸气性和呼气性NAA神经元，它们没有从这些传入纤维接受直接的突触输入。所有研究的神经元类型在吸气和呼气期间均显示出突触后活动。突触活动最小的时期是呼吸相之间的过渡时期。大多数呼吸神经元的输入电阻与呼吸周期平行变化。在Rβ神经元和一些吸气性迷走神经元中观察到呼气期间输入电阻急剧下降。在吸气性延髓脊髓神经元中未观察到这种情况。在稳定的细胞内记录中，通过注射氯化物后IPSP反转，在53个呼吸神经元中的52个中证明了周期性突触后抑制。最大膜电位通常在呼吸相过渡的某个时期达到。给出了其他一些未能证明这些IPSP的原因，并讨论了其他发现与这些发现之间的差异。得出的结论是，延髓呼吸神经元之间确实存在相互抑制，并且是一种普遍现象。有人认为，相互抑制是传入输入呼吸门控的基本机制。从神经元活动期膜去极化模式的变化推断出可能存在回返性抑制。
