碘化二甲基木防己碱对神经肌肉接头传递的作用

碘化二甲基木防己碱(dimethyltrilobine iodide简称DTI)有降压作用,抗心律失常作用和骨骼肌松驰作用。本文采用离体大白鼠膈神经膈肌和小鸡颈二腹肌标本,进一步观察了DTI对神经肌肉系统的作用,并对其作用机制作了初步分析。选体重250～350 g大白鼠,按文献方法制备离体膈神经膈肌标本,固定在含循环Tyrode液的肌槽中,用JSD-731-C型刺激器,超强方波脉冲(波宽0.2ms,频率6/min)刺激膈神经,膈肌收缩用XWT-204型平衡记录仪描记。

EFFECTS OF DIMETHYLTRILOBINE IODIDE ON NEUROMUSCULAR TRANSMISSION

Experiments were carried out on isolated rat phrenic nerve diaphragm preparations and Chick biventer cervicis preparations. Dimethyltrilobine iodide (DTI) blocked neuro-muscular transmission without affecting the conductivity of the nerve and muscle contractile response to direct stimulus. The actions of DTI was compared with those of curare in vitro. The ID₅₀ of DTI and curare were found to be 1.9 × 10^-5M and 8.0×10^-7M respectively, DTI reduced the sensitiyity of the chick biventer cervicis muscle to Ach. High Ca²⁺ antagonised the effect of DTI on neuro-muscular transmission. It is concluded that DTI produces a neuromuscular block by acting on the Ach receptor.