Cardiovascular activity of Carnigen in normotone and in experimentally hypotone dogs

Activity of Carnigen on the cardiovascular system, following intraduodenal and intravenous application, was investigated in normotone and hypotone dogs anaesthetized with sodium pentobarbital, 35-40 mg/kg intraperitoneally. Intraduodenal application of 1 and 3 mg Carnigen/kg caused an increase in blood pressure and tachycardia. The total peripheral resistance was lessened, in normotone as well as hypotone dogs, whereas the cardiac output and stroke volume were augmented. A rise in myocardial inotrophy and cardiac work in combination with a moderate increase in left ventricular O2 consumption also occurred as result of the action of Carnigen. An increase in the central and peripheral venous pressure was registered during continuous infusion of Carnigen. Coronary flow was also raised, in a dose dependent manner within the range of 0.1 to 1 mg Carnigen/kg i.v. The rise in arterial blood pressure is due to an increase in cardiac output, resulting from the positive inotropic action of this compound on the myocardium. The reduction in arterial resistance can be explained on the basis of a possible interaction between the inosine, released from Carnigen, and the adenosine already present in the system.