[Change of sympathetic efferent discharges in different regions during the Bezold-Jarisch reflex in rabbit]

In 46 anesthetized rabbits, the sympathetic efferent discharges in different vascular regions were recorded during the Bezold-Jarisch reflex induced by intracoronary injection of nicotine. The discharges of renal nerve, cardiac nerve, splenic nerve, ramus of stellate ganglion to cervical plexus and ramus of superior cervical ganglion to external carotid artery decreased significantly following injection of nicotine. The decrease in efferent discharge is more prominent in renal, cardiac and splenic nerves than in the other two nerves. These results demonstrated that the reduction in discharge of sympathetic efferent fibers of different regions and hence decrease in total peripheral resistance might play a significant role in initiating hypotension during the Bezold-Jarisch reflex.