过刊浏览

安定减低家兔膈神经放电幅度的机制分析

郑文安, 徐宁善, 张镜如

上海第一医学院生理学教研室. 上海

摘要

该实验室曾经报道静脉注射安定对于清醒、麻痹、人工呼吸的家兔具有减低膈神经放电幅度、加快呼吸频率,缩短吸气时程(T_(I))和呼气时程(T_(E)),降低动脉血压等作用。该工作在35只家兔中进一步分析了某些药物对安定的这些作用的影响。GABA 降低膈神经放电幅度和动脉血压,这与安定的作用相同,但 GABA 延长T_(I)、T_(E)和减慢呼吸频率,与安定的作用相反。事先用氨基酸脱羧酶抑制剂异烟肼处理,或用 GABA 受体拮抗剂印防己毒素处理,可阻遏安定减低膈神经放电幅度的作用。在事先用印防己毒素处理的家兔中,可见安定缩短 T_(I)、T_(E)的作用不受影响。

关键词： 安定; GABA; 异烟肼; 印防己毒素; 纳洛酮; 赛庚啶; 膈神经放电; 血压

Analysis of depressant effect of diazepam on the amplitude of phrenic nerve discharge in rabbits

Zheng wenan, Xu Ningshan, Zhang Jingru

Department of Physiology, Shanghai First Medical College. Shanghai, China

Abstract

Our previous study indicated that in awake rabbits diazepam depressed the amplitude of phrenic nerve discharge, increased respiratory rate, shortened both the inspiratory and expiratory durations (T_(I) and T_(E)) and lowered arterial blood pressure. In the present experiments, the effects of some drugs on the,above-mentioned diazepam actions were further examined in 35 rabbits. GABA caused depression of the amplitude of phrenic discharge and blood pressure, an effect similar to that of diazepam. But, different from diazepam, GABA prolonged both T_(I) and T_(E), and thus decreased the respiratory rate. Pretreatment of either isoniazid, an amino acid decarboxylase inhibitor, or GABA receptor antagonist picrotoxin prevented the depressant effect of diazepam on the amplitude of phrenic discharge. However, the shortening of T_(I) and T_(W) by diazepam was not affected in pretreatment of picrotoxin. When given alone, diazepam produced a fall on blood pressure lasting for more than one hour. In isoniazid or picrotoxin pretreated rabbits, however, diazepam exhibited a transient depressor effect lasting only 2 to 10 minutes. Neither naloxone (an opiate receptor antagonist) or cyproheptadine (a serotonin receptor antagonist) pretreatment affected the depressant effects of diazepam upon the amplitude of phrenic discharge and blood pressure. The results obtained suggest that the depressant effect of diazepam on the amplitude of phrenic discharge is mediated by GABA, while endorphins and serotonin seem not to be involved. Prolongation of the depressor effect of diazepam is possibly attributable to the participation of GABA, since following block of GABA synthesis or GABA receptors diazepam lowered blood pressure only transiently.

Key words: Diazepam;GABA;Isoniazid;Picrotoxin;Naloxone;Cyproheptadine;Phrenic discharge;Blood pressure

收稿日期：　　录用日期：

通讯作者：　　E-mail:

引用本文：

郑文安, 徐宁善, 张镜如. 安定减低家兔膈神经放电幅度的机制分析[J]. 生理学报 1985; 37 (2): .

Zheng wenan, Xu Ningshan, Zhang Jingru. Analysis of depressant effect of diazepam on the amplitude of phrenic nerve discharge in rabbits. Acta Physiol Sin 1985; 37 (2): (in Chinese with English abstract).