Effects of nonpulsatile left heart bypass on renal sympathetic nerve activity in rabbits

To determine the effects of nonpulsatile left heart bypass (LHB) on sympath etic nerve activity the renal sympathetic nerve activity (RSNA) was directl y measured in rabbits. In anaesthetized rabbits (n=6), LHB was instituted w ith a centrifugal pump. Before and during LHB, heart rate (HR), arterial pr essure (AP), central venous pressure (CVP), left atrial pressure (LAP) and spike counts of RSNA were measured. After bilateral vagotomy (section of th e afferent inputs of the cardiac reflex are) the same parameters were measu red before and during LHB. Data were obtained at the same level of mean AP before and during LHB. Mean AP and CVP were not changed by LHB before and a fter vagotomy LAP was significantly decreased by LHB before and after vagot omy. RSNA and HR were not significantly changed by LHB before and after vag otomy Our results clarify the complex baroreflex control during nonpulsatil e LHB and indicate that RSNA is not altered by LHB.