罗库溴铵对家兔面神经和肢体神经支配的肌肉突触前膜乙酰胆碱释放量和释放方式的影响

Effect of rocuronium on the amount and mode of presynaptic acetylcholine release in the muscles innervated by facial nerve and somatic nerve in rabbit

目的比较家兔面神经支配的口轮匝肌和肢体神经支配的腓肠肌在非去极化肌肉松弛药罗库溴铵作用下的乙酰胆碱量子式和非量子式释放量,分析面神经和肢体神经支配的肌肉对罗库溴铵敏感性差异的机制及其与两种神经肌接头突触前膜乙酰胆碱释放量和释放方式的关系。方法成年家兔6只,分别取双侧面神经主干和相连接的口轮匝肌肌条、胫神经主干和相连接的腓肠肌肌条,右侧肌条为未处理组,相对应的左侧肌条为处理组。处理组在加入任何药物之前,在浴槽中先加入罗库溴铵10μg/mL。采用细胞内微电极记录法检测各组肌条的微终板电位(MEPP)的振幅和频率、终板电位(EPP)的振幅、加入对氧磷(Paraoxon)后的静息膜电位(RMP),以及加入Paraoxon和筒箭毒碱后的RMP;比较各组间肌肉的MEPP振幅和频率、EPP振幅,乙酰胆碱量子式释放量(以EPP/MEPP表示)和非量子式释放量(以RMPparaoxon-RMPparaoxon+筒箭毒碱表示)。在罗库溴铵作用下,神经肌接头的乙酰胆碱量子式或非量子式释放量的变化以未处理组与相对应的处理组的差值表示。结果未处理组面神经支配的口轮匝肌EPP、量子式释放量均显著高于同组胫神经支配的腓肠肌(P值均<0.05)。未处理组面神经支配的口轮匝肌和胫神经支配的腓肠肌的EPP、量子式释放量均显著高于处理组相应部位(P值均<0.05),MEPP、RMPparaoxon、RMPparaoxon+筒箭毒碱、非量子式释放与处理组相应部位的差异均无统计学意义(P值均>0.05)。未处理组与处理组胫神经肌接头的量子式释放量的差值为7.15±2.36,显著高于面神经肌接头的3.49±1.25(P<0.05)。结论罗库溴铵对肢体神经肌接头突触前膜乙酰胆碱的量子式释放功能的抑制程度大于面神经肌接头,而其对两种神经肌接头的非量子式释放功能的抑制作用无明显差异。

Objective To compare quantal release with non-quantal release of acetylcholine in orbicularis oris innervated by facial nerve and gastrocnemius innervated by somatic nerve after applying rocuronium in rabbit in vitro, and to analyze the mechanism of the sensitivity difference between muscles innervated by facial nerve and somatic nerve to rocuronium and the relationship between the amount and mode of presynaptic acetylcholine （ACh） release. Methods The orbicularis oris muscle strips associated with the facial nerves and the gastrocnemius muscle strips associated with the peroneal nerves were isolated from both sides of 6 adult rabbits. The left muscles strips were designed as treatment group and the right sides were taken as control group. The muscles in the treatment group were bathed with rocuronium 10 pg/mL before the presence of any other drugs. The intracellular microelectrode gauge was used to measure the miniature endplate potentials （MEPP） and their frequencies, the endplate potentials （EPP）, the resting membrane potentials （RMP） with the presence of paraoxon in bath, and RMP with the presence of both paraoxon and tubocurarine in bath. The MEPP amplitude and their frequency, EPP amplitude, quantal release amount （expressed as EPP/MEPP）, and non-quantal release amount （expressed as RMPp -RMP p ＋ubr） was compared between groups. Results In control group, EPP of orbicularis oris innervated by facial nerve and the amount of ACh quantal release were significantly higher than that of gastrocnemius innervated by somatic nerve （both P〈0.05）. EPP of orbicularis otis innervated by facial nerve and gastrocnemius innervated by somatic nerve and ACh quantal release in control group were significantly higher than that of treatment group （both P 〈 0.05）. There were no significant differences in terms of MEPP, MEPP、RMPparaomav-RMP paraoxoa＋, or ACh non-quantal release between two groups （all P〉0.05）. Conclusion Rocuronium can significantly inhibit AOh quantal release in somatic neuromuscular junctions as compared with facial neuromuscular junctions. However, there is no significant difference in AOh non-quantal release inhibited by rocuronium between facial or somatic neuromuscular junctions. （Shanghai Meal J, 2013, 36 ： 711-715）