Cardiorespiratory responses following isoproterenol injection in rabbits

Publisher Website
Google Scholar
Abstract
Receptor sites for the ventilatory response to isoproterenol were investigated in anesthetized rabbits with bolus injections in the common carotid artery (i.a.) and in the vena cava (i.v.). The delay from injection to the increase in ventilation (T.ovrhdot.VE) was significantly shorter following i.a. (1.5 s) compared to i.v. injections (about 5 s). The delay to the increase in heart rate (THR) was significantly shorter after i.v. (about 4.5 s) than after i.a. injections (12.5 s). When isoproterenol and NaCN injections were compared, there was no difference in T.ovrhdot.VE. Following carotid body resection, the .ovrhdot.VE response to isoproterenol was greatly reduced after i.v. and i.a. injections; however, THR was unaffected. In intact animals breathing 100% O2, the .ovrhdot.VE [minute ventilation] response to isoproterenol was significantly reduced with no change in T.ovrhdot.VE or in the heart rate response. The ventilatory increase following the injection of isoproterenol is probably due primarily to direct stimulation of the carotid bodies.