家兔迷走神经传入活动对膈神经呼气相放电的影响

作者用麻醉家兔34只,切断其神经、改变肺容积、吸入SO_2以选择性阻断肺牵张感受器活动等方法,探查迷走神经传入活动对膈神经呼气相放电(ED)的作用。观察结果:平静自然呼吸家兔被切断双侧颈迷走神经后,ED减弱;扩张肺引起肺牵张反射时,ED先增强后减弱,而当肺被萎陷或过度扩张时则ED增强;以SO_2选择性阻断肺牵张感受器的活动后,切断双侧颈迷走神经,ED不再变化。提示:平时起源于肺牵张感受器的传入活动对ED有紧张性增强作用。

INFLUENCE OF VAGAL INPUTS ON PHRENIC DISCHARGES DURING THE EXPIRATORY PHASE

Experiments to determine the effect of vagal afferent activity on phrenic discharges during the expiratory phase (ED) were carried out on 34 anesthetized rabbits. In eupneic rabbits, ED declined after bilateral cervical vagotomy. When the pulmonary stretch reflex was induced by moderately inflating the lungs, the ED increased first and then decreased. However, when the lungs were deflated or overinflated, the ED increased and was accompanied by breathing pattern changes, Similar to the effects of lung irritant receptor and/or J receptor stimulation. After the pulmonary stretch receptors were selectively blocked by SOa inhalation, no ED changes were observed after bilateral cervical vagotomy. This suggests that vagal inputs originating from the pulmonary stretch receptors augment ED tonically in normal breathing.