吗啡抑制呼吸与脑中乙酰胆碱含量间的关系

本文在观察兔呼吸的同时,用放射免疫法测定延髓和脑桥Ach含量。iv吗啡4.0mg/kg,呼吸频率减慢,延髓和脑桥Ach含量下降,呼吸频率及Ach含量一时间曲线有很好的对应关系。iv吗啡2.0—8.0mg/kg,呼吸频率和Ach含量均呈剂量依赖性下降,两者有正相关。icv纳洛酮0.2mg/kg,能拮抗脑桥但不能拮抗延髓Ach含量下降作用。结果表明吗啡抑制呼吸与低位脑干Ach含量下降有关。

RELATIONSHIP BETWEEN MORPHINE-INDUCED RESPIR- ATORY DEPRESSION AND BRAIN ACETYLCHOLINE CONTENT IN RABBITS

The respiratory rate and acetylcholinc ( Ach ) contents of medulla oblo-ngata and pons by radioimmunoassay were determined 15, 30, 60 min after administration of morphine (4.0 mg/kg iv ) to rabbits. While respiratory rate was reduced,Ach contents were decreased from 33.80 5.99 to 20.49 6.52, 14.02 1.50, 15.20 0.65 pmol/mg tissue in pons and from 25.95 5.99 to 18.52 4.45, 10.14 1.95, 10.98 1.44 pmol/mg in medulla oblon-gata respectively. Varying the dose of morphine ( 2.0, 4.0, 8.0mg/kg, iv ) caused dosage-dependent reduction of respiratory rate and decrease of Ach content in pons ( from 33.80 5.99 to 25.14 4.57, 20.49 6.52, 18.85 1.78 pmol/mg)and in medulla oblongata(from 25.95 5.99 to 20.31 3.51, 18.52 4.45, 13.07 1.79 pmol/mg). The time course and dose-effect of respiratory depression correlated with those of the decline of Ach contents in lower brain stem(r=0.9301, P<0.01) .Naloxone 0.2 mg/kg icv antagonized morphin-induced decrease of Ach content in pons butno tin medulla blongata. The above results showed that the respiratory depression by morphine was related to the reduction of Ach in lower brain stem.