Prevention of endotoxin-induced increase of cerebral oxygen consumption in dogs by propranolol pretreatment.

Cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) were studied in experimental endotoxic shock in dogs. Eight animals were pretreated with a beta-adrenoceptor blocking agent, propranolol (PPL), per os 12 mg/kg once a day for 7 days. Ten animals served as controls. After an intravenous injection of endotoxin, 1 mg/kg, CBF decreased in both groups, with no significant differences between the groups. CMRO2 increased in the control animals by about 18% from the baseline value both 1 and 2 h after the injection of endotoxin. CMRO2 in the PPL-pretreated animals was unchanged after endotoxin. The CMRO2-reactions to endotoxin in control and PPL animals were significantly different after both 1 and 2 h (P less than 0.05). The present results indicate that the increase in CMRO2 following intravenous endotoxin is mediated via beta-adrenoceptors.