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 < 0.05). The present results indicate that the increase in CMRo2 following intravenous endotoxin is mediated via beta-adrenoceptors.