Effects of muscle spindle afferents invoked by intraarterial injection of succinylcholine on the phrenic nerve discharges / 西安交通大学学报(医学版)

ABSTRACT

ObjectiveTo study wether muscle spindle afferents have the regulating effects on res piratory movement. MethodsExperiments were performed on 36 anesthetized, immobilized, bilater ally vagotomized and artificially ventilated rabbits. Using the phrenic nerve discharge as the respira tory index, this experiment have assessed the effects of muscle spindle afferents invoked by intraarte rial injection of succinylcholine(Sch) on respiration. Results①In 40(63.49% ) cases which had the facilitated effects, 23 (36.51%) cases had the effect of prolonged inspiratory phase and 17 (26.98 % ) cases had the effect of attenuated expiratory phase and augmented respiratory frequency. In addition,there were 11(17.46% ) cases which had the attenuated effects,and 4(6.35% ) cases which had the biphasic effects,and 8(12.7% ) cases which had no effects;②The effect of prolonged inspiratory phase mainly showed the prolongation of inspiratory duration(Ti), but the effect of at tenuated expiratory phase and augmented respiratory frequency mainly showed the decrease of expi ratory duration (Te) and the augmentation of respiratory frequency(RF) ;③The above facilitated ef fects of Sch were significantly attenuated by intramuscular application of bupivacaine to destroy the muscle spindles. ConclusionThese results suggest that muscle spindle afferents induced by intraar terial injection Sch have a significant facilitated effect on respiration.