已知箭毒(d—tubocurarine,d—TC)既有典型的突触后抑制作用,又有明显的影响突触前递质释放的作用。但在同一标本上同时定量比较其突触前和突触后的作用则尚未见报道,对d—TC突触前作用的性质也无统一看法。我们在大白鼠离体不均匀牵张膈肌标本上,用细胞内微电极同时记录运动终板区的微终板电位(MEPP)、终板电位(EPP) 和微电泳外源性乙酰胆碱(ACh)诱发的乙酰胆碱电位(AChP),并以AChP幅 Known dirus (d-tubocurarine, d-TC) both the typical post-synaptic inhibitory effect, but also significantly affect the presynaptic transmitter release. However, the quantitative and simultaneous presynaptic and post-synaptic effects on the same specimen have not been reported yet and there is no uniform view on the nature of the presynaptic d-TC. We recorded the endplate potential (MEPP), endplate potential (EPP) and exogenous ACh in the motor endocardium simultaneously with the intracellular microelectrode in the non-uniform distraction diaphragm of rats. Induced acetylcholine potentials (AChP), and with AChP amplitude