回苏灵引起家兔膈神经和胫神经痉挛性放电的机制分析

本工作在28例局部麻醉、肌肉麻痹的家兔上进行。实验观察到静脉注射大剂量回苏灵(1.5mg/ kg)后,在胫神经、膈神经及脑干孤束核(NTS)区与网状结构等部位均可记录到痉挛性放电。其中胫神经上先出现紧张性高频放电,后转为阵挛性排放,一般在50—100min 后恢复。膈神经也可出现类似放电,但其排放节律比胫神经快,两者不完全同步;在恢复期,吸气放电与痉挛性排放可交替出现。高位离断脊髓后,胫、膈神经的痉挛性放电即消失。NTS 区的吸气相关单位所出现的痉挛性排放,其频率与膈神经的不完全同步;但在脑干网状结构可找到与胫神经、膈神经痉挛性排放基本同步的放电单位,且孤立脑干,仍可见该单位的痉挛性放电。以上结果提示,回苏灵痉挛性放电的发源部位主要在脑干网状结构。切断脊髓背束及外侧束的大部,保留网状脊髓束和脊髓网状束,不影响胫,膈神经的痉挛性放电;脊髓半横切后,同侧胫、膈神经的痉挛性放电则消失。

ANALYSES OF MECHANISM OF DIMEFLINE-INDUCED CONVULSIVE DISCHARGES IN PHRENIC AND TIBIAL NERVES

Experiments were carried out on 28 locally anesthetized,vagotomized,immo-bilized with Flaxedil and artificially ventilated rabbits.Dimefline-induced con-vulsive discharges were observed in tibial and phrenic nerves,nucleus tractus soli-tarius(NTS)and brainstem reticular formation.Tonic and clonic convulsive burstoccurred in all of these areas after intravenous injection of dimefline(1 .5mg/kg).There were partial synchronous bursts between units in brainstem reticular forma-tion and peripheral nerves.From the results of transection of brainstem and spi-nal cord we deduce that brainstem reticular formation might be the main originalsites where dimefline-induced convulsions are induced.Tractotomy experimentsindicate that discharge in peripheral nerves may be mediated by reticulospinal tract.