McWilliam P N, Gray S J
Department of Cardiovascular Studies, University of Leeds, UK.
J Auton Nerv Syst. 1990 Jul;30(3):233-8. doi: 10.1016/0165-1838(90)90254-g.
The innervation of tracheal smooth muscle in the ferret has been studied by monitoring pressure changes in a fluid-filled segment of trachea in pentobarbitone anaesthetized animals. Stimulation of the peripheral cut end of the vago-sympathetic trunk elicited increases in trachea segment pressure only when activity was evoked in non-myelinated efferent axons, myelinated axons were without effect. Such excitatory responses were blocked by atropine. After atropine and elevation of trachealis muscle tone with 5-hydroxytryptamine, stimulation of the vago-sympathetic trunk produced a fall in tracheal segment pressure. These inhibitory responses were completely blocked by bretylium tosylate in six animals and markedly reduced in a seventh. It is concluded that contraction of tracheal smooth muscle in the ferret is cholinergically mediated and solely dependent on activity in non-myelinated vagal efferent axons and that inhibition is mediated by noradrenaline released from sympathetic nerve endings. A non-adrenergic inhibitory system would not appear to be present in the ferret.
通过监测戊巴比妥麻醉动物的充满液体的气管段中的压力变化，对雪貂气管平滑肌的神经支配进行了研究。仅当无髓传出轴突产生活动时，刺激迷走-交感干的外周切断端才会引起气管段压力升高，有髓轴突则无作用。这种兴奋性反应被阿托品阻断。在用5-羟色胺提高气管肌张力并给予阿托品后，刺激迷走-交感干会导致气管段压力下降。在六只动物中，这些抑制性反应被甲苯磺酸溴苄铵完全阻断，在第七只动物中则明显减弱。得出的结论是，雪貂气管平滑肌的收缩是由胆碱能介导的，并且仅依赖于无髓迷走传出轴突的活动，而抑制作用是由交感神经末梢释放的去甲肾上腺素介导的。雪貂似乎不存在非肾上腺素能抑制系统。
