EFFECT OF ATRACURIUM, VECURONIUM, PANCURONIUM AND TUBOCURARINE ON RENAL SYMPATHETIC-NERVE ACTIVITY IN BARORECEPTOR DENERVATED DOGS

The mechanism of arterial hypotension induced by non-depolarizing neur omuscular blocking agents may be multifactorial and differ between dru gs. The purpose of this study was to evaluate the effect of high-dose atracuricum and equivalent doses of other non-depolarizing neuromuscul ar blocking agents on haemodynamic state and sympathetic nervous activ ity. In studies on 24 mongrel dogs anaesthetized with alpha-chloralose , the left kidney was exposed retreperitoneally and renal sympathetic nerve activity was recorded continuously after bilateral sine-aortic d enervation and cervical vagi section. The dogs were allocated to four groups, atracurium 1.5 mg kg(-1), tubocurarine 0.3 mg kg(-1), pancuron ium 0.3 mg kg(-1) or vecuronium 0.3 mg kg(-1) was administered to six dogs in each group. Histamine 1 mu g kg(-1) was given to two dogs in e ach group, 1 h before administration of neuromuscular blocking agents. We observed that atracurium and tubocurarine significantly decreased arterial pressure, heart rate and renal sympathetic nerve activity (P < 0.05), but pancuronium and vecuronium did not Histamine-induced arte rial hypotension but did not affect heart rate or renal sympathetic ne rve activity. As both arterial and cardiopulmonary baroreflex pathways were inactivated in these animals, we conclude that atracurium decrea sed arterial pressure by suppressing efferent sympathetic nerve activi ty in a manner similar to that of tubocurarine.