Takeda R, Haji A, Hukuhara T
Department of Pharmacology, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Japan.
Pflugers Arch. 1990 Jun;416(4):375-84. doi: 10.1007/BF00370743.
The effects of two anesthetic agents, halothane and thiopental, on the membrane potential trajectory of respiratory-related neurons in the ventral respiratory group were investigated in decerebrate cats, of which the carotid sinus and vagal afferents were denervated. Infusion of halothane (2% for 90 s) depolarized the membrane in nearly half of the inspiratory (12/21), post-inspiratory (10/26) and expiratory (4/6) neurons and caused hyperpolarization in the rest of the population. Thiopental (2.5 mg/kg i.v.) produced depolarization in 11 inspiratory and 10 post-inspiratory neurons and hyperpolarization in 1 expiratory, 4 inspiratory and 7 post-inspiratory neurons. In both hyperpolarized and depolarized neurons, reduction of the respiratory membrane potential fluctuations and an increase of input resistance were commonly observed. Both drugs depressed spontaneous firing in most of the neurons studied. An increase of firing was observed in 9 out of 47 depolarized cells. These two contrasting effects on the membrane potential trajectory occurred similarly in the known groups of respiratory neurons, but the response of a given cell was consistent for the two anesthetic agents. The present results demonstrate that the anesthetic drugs exert various influences on the ventral respiratory group neuron population in maintaining the membrane potential trajectory and discharge activity. This may reflect a functional heterogeneity in the bulbar respiratory network of neurons.
在去大脑猫身上研究了两种麻醉剂氟烷和硫喷妥钠对腹侧呼吸组中与呼吸相关神经元膜电位轨迹的影响，这些猫的颈动脉窦和迷走神经传入神经已被去神经支配。输注氟烷（2%，持续90秒）使近一半的吸气神经元（12/21）、吸气后神经元（10/26）和呼气神经元（4/6）的膜去极化，并使其余神经元超极化。硫喷妥钠（静脉注射2.5mg/kg）使11个吸气神经元和10个吸气后神经元去极化，使1个呼气神经元、4个吸气神经元和7个吸气后神经元超极化。在超极化和去极化的神经元中，通常都观察到呼吸膜电位波动的减少和输入电阻的增加。两种药物都抑制了大多数研究神经元的自发放电。在47个去极化细胞中有9个观察到放电增加。这两种对膜电位轨迹的相反作用在已知的呼吸神经元组中同样出现，但给定细胞对这两种麻醉剂的反应是一致的。目前的结果表明，麻醉药物在维持膜电位轨迹和放电活动方面对腹侧呼吸组神经元群体有多种影响。这可能反映了延髓呼吸神经元网络中的功能异质性。
