Holtman J R, King K A
Department of Pharmacology, University of Kentucky, College of Medicine, Lexington 40536.
Eur J Pharmacol. 1988 Nov 1;156(2):181-7. doi: 10.1016/0014-2999(88)90320-2.
Effects of intracisternal administration of the gamma-aminobutyric acid receptor agonist, muscimol, on recurrent laryngeal and phrenic nerve activities were assessed in the cat. Muscimol (0.1-2.4 micrograms) produced a dose-related inhibition of the respiratory activity in both of these nerves. The inhibition was seen as a decrease in the amplitude of nerve activity with no significant change in respiratory rate. The ED50 values for muscimol and its 95% confidence interval for inhibition of the inspiratory activity in the recurrent laryngeal and phrenic nerves were 0.22 micrograms (0.17-0.29) and 0.27 micrograms (0.19-0.38), respectively. The potency of muscimol for inhibition of these nerve activities was not significantly different. Expiratory activity in the recurrent laryngeal nerve was completely inhibited prior to either the inspiratory activity in this nerve or in the phrenic nerve. Intracisternal administration of the gamma-aminobutyric acid receptor antagonist, bicuculline, rapidly reversed the inhibition in both nerves. Reversal times for inhibition of the inspiratory activities in the recurrent laryngeal and phrenic nerves were not significantly different. Return of inspiratory activity in each nerve always preceded the return of expiratory activity in the recurrent laryngeal nerve. These results demonstrate that CNS gamma-aminobutyric acid receptors are involved in the regulation of respiratory motor outflow to the larynx as well as the diaphragm.
在猫身上评估了脑池内注射γ-氨基丁酸受体激动剂蝇蕈醇对喉返神经和膈神经活动的影响。蝇蕈醇（0.1 - 2.4微克）对这两条神经的呼吸活动均产生剂量相关的抑制作用。这种抑制表现为神经活动幅度降低，而呼吸频率无显著变化。蝇蕈醇抑制喉返神经和膈神经吸气活动的半数有效量（ED50）值及其95%置信区间分别为0.22微克（0.17 - 0.29）和0.27微克（0.19 - 0.38）。蝇蕈醇抑制这些神经活动的效能无显著差异。喉返神经的呼气活动在该神经或膈神经的吸气活动之前就被完全抑制。脑池内注射γ-氨基丁酸受体拮抗剂荷包牡丹碱可迅速逆转两条神经的抑制作用。抑制喉返神经和膈神经吸气活动的逆转时间无显著差异。每条神经吸气活动的恢复总是先于喉返神经呼气活动的恢复。这些结果表明，中枢神经系统γ-氨基丁酸受体参与了对喉部以及膈肌呼吸运动输出的调节。
