Evidence for selective inhibition of sympathetic outflow by oxotremorine

Unlike numerous centrally acting hypotensive substances which decrease blood pressure and sympathetic outflow, the muscarinic agonist oxotremorine failed to reduce heart rate in a prior study. In the present series of experiments oxotremorine decreased blood pressure and efferent renal nerve activity in anesthetized cats but, in contrast to clonidine, it did not inhibit cardiac sympathetic nerve activity or lower heart rate. Therefore, it is concluded that oxotremorine does not produce uniform sympathetic inhibition and that outflow is depressed selectively.