罗库溴铵对大鼠膈肌神经肌肉接头微终板电位及终板电位的影响

Effects of rocuronium on micro-endplate potential and endplate potential in isolated diaphragmatic muscle preparation of rat

目的 利用成年大鼠膈肌膈神经不均匀牵拉标本 ,研究罗库溴铵对神经肌肉接头部位的电生理学影响。方法 成年健康Wistar大鼠快速处死制备离体大鼠不均匀牵张膈肌膈神经标本 (INSMP) ,记录正常微终板电位 (MEPP)和终板电位 (EPP) ,观察相当于大鼠 4×ED95、2×ED95、1×ED95和 0 5×ED95剂量时的血药浓度的罗库溴铵对MEPP频率和幅度及EPP幅度的影响。结果 罗库溴铵在2 5 μg/ml浓度时对正常INSMP上的MEPP的频率及幅度无明显影响 ;5 μg/ml时 ,在 5min时点对MEPP频率及幅度产生明显抑制作用 (P <0 .0 5 ) ;10～2 0 μg/ml时 ,在 1min时点即对MEPP频率及幅度产生抑制作用 (P <0 0 1) ;2 0 μg/ml在 3min时点、10 μg/ml在 5min时点即能完全抑制MEPP的产生。罗库溴铵在 2 .5 μg/ml浓度时对正常INSMP上的EPP的幅度无明显影响 ;5 μg/ml时 ,在 3min时点开始对EPP幅度产生明显抑制作用(P <0 .0 5 ) ;10～ 2 0 μg/ml时 ,在 1min时点即产生对EPP幅度的抑制作用 (P <0 .0 1) ;随着时间的延长和剂量的加大 ,罗库溴铵对EPP幅度的抑制作用逐渐加强。结论 罗库溴铵能减少突触前递质的释放 ,推测它可能有早期较强的突触前作用。

Objective To investigate the effects of rocuronium on the neuromuscular junction of rat diaphragm. Methods One hundred and sixty rats were used in the study which was approved by the Animal Care Committee of the General Hospital of PLA. In isolated non-uniformly stretched muscle preparation (INSMP) of rat diaphragm, micro-endplate potentials (MEPP) and endplate potentials (EPP) were recorded simultaneously with one microelectrode of one endplate. The effects of rocuronium in dosages of 2.5, 5, 10, 20μg/ml on the amplitude and frequency of MEPP and the amplitude of EPP were observed. Results Rocuronium could decrease both the amplitude and frequency of MEPP obviously and the onset time was 1min after drug administration. The amplitude of EPP was depressed by rocuronium in a dose of 5μg/ml at 3min. Neither 2.5μg/ml nor 0.5μg/ml of rocuronium produced any effect on the amplitude of EPP. Conclusion The results indicated that rocuronium might produce a rapid and early presynaptic effect on neuromuscular junction in INSMP in rats.