Disturbed adrenergic regulation of coronary flow in the guinea-pig heart after endotoxin

We investigated the functional responsiveness of alpha- and beta-adrenoceptors in the isolated guinea-pig heart and coronary vascular system, 4 days after pretreatment with endotoxin. It was found that endotoxin reduced the flow-increasing effect of salbutamol and enhanced the flow-decreasing effect of B-HT 920. The positive chronotropic and inotropic effects of dobutamine and salbutamol and the flow-decreasing effect of phenylephrine were not influenced by endotoxin pretreatment. It is concluded that bacterial endotoxin induces alpha 2-adrenoceptor hyperreactivity and beta 2-adrenoceptor impairment in the coronary vascular system of the guinea-pig heart.