筒箭毒碱对琥珀胆碱引起肌梭传入放电的抑制

The suppression by tubocurarine on the increased afferent discharge from the muscle spindle caused by succinylcholine

目的 研究筒箭毒碱 (TC)对琥珀胆碱 (SCh)引起肌梭传入放电的影响。方法 以大鼠为对象 ,在支配腓肠肌的神经上分离神经细束 ,引导肌梭的传入放电。以放电频率峰值 (DPF)、放电频率最大增值 (MIF)和峰频率 (PF)出现的时间为指标 ,观察TC对SCh引起肌梭传入放电的影响。结果 ①注射TC 0 .0 0 1mmol·kg- 1 5min后再注射SCh0 .0 0 5mmol·kg- 1 ,DPF和MIF分别降低到对照值的 4 2 .2 %和 2 4 .0 % ,PF出现时间后移 71.9s;SCh的剂量不变 ,当TC的剂量增加到 0 .0 0 3mmol·kg- 1 时 ,DPF和MIF分别降低到 10 .4 %和 8.7% ,PF出现时间后移 96 .3s ;当TC的剂量增加到 0 .0 0 5mmol·kg- 1 时 ,则可完全抑制SCh引起的肌梭传入放电。②分别在注射TC 0 .0 0 1mmol·kg- 1 后35min和 70min再注射SCh 0 .0 0 5mmol·kg- 1 ,则DPF降低到对照值的 5 7.4 %和 6 9.3% ,MIF降低到 4 6 .8%和6 5 .8% ,PF出现时间后移 4 5 .9s和 2 8.7s。结论 TC对SCh引起的肌梭传入放电有明显的抑制作用 。

Objective To study the effect of tubocurarine (TC) on the increased afferent discharge from the muscle spindle caused by succinylcholine (SCh). Methods The nervous filaments of rats were separated from muscular nerves innervating the gastrocnemius muscles and afferent discharge from the muscle spindle was recorded. The effect of suppression by TC on the increased afferent discharge caused by SCh was measured by counting the decrease in discharge peak frequency (DPF) and maximum increase frequency (MIF), by counting the time of peak frequency (PF) appearing delayed than the control. Results ① SCh 0.005?mmol·kg -1 was injected after 5 minutes of TC 0.001?mmol·kg -1 injected, DPF and MIF were reduced to 42.2% and 24.0% of the control values, respectively, the time of PF appearing was delayed by 71.9?s. When the dose of TC increased to 0.003?mmol·kg -1, DPF and MIF were reduced to 10.4% and 8.7%, the time of PF appearing was delayed by 96.3?s. When dose of TC was increased to 0.005?mmol·kg -1, the increase in the afferent discharge from the muscle spindle induced by SCh completely disappeared. ② After 35 and 75 minutes of TC 0.001?mmol·kg -1 injected, SCh 0.005?mmol·kg -1 was injected respectively. DPF was reduced to 57.4% and 69.3%, MIF was reduced to 46.8% and 65.8%, the time of PF appearing was delayed by 45.9?s and 28.7?s. Conclusion TC has a remarkable suppressive effect on the increase in afferent discharge from the muscle spindle induced by SCh. The suppression of TC is dose-dependent and the action of SCh and TC on muscle spindle is in competition.