Inhibitory Modulation on the Reflex Tracheal Constriction Induced by Afferent Vagal Stimulation

抄録

Afferent cervical vagal electrical stimulation caused a reflex tracheal constriction. Atropine changed the tracheal constriction into a tracheal dilatation that was almost inhibited by propranolol. In the hypertonic trachea with 5-hydroxytryptamine, a reflex dilatation following a constriction was observed by afferent vagal stimulation. The reflex dilatation was inhibited about 50% by propranolol and was abolished by hexamethonium. These results suggest that the adrenergic and nonadrenergic inhibitory innervations may mediate the reflex tracheal dilatation, especially in a hypertonic tracheal condition.