Role of Venous Return in the Cardiovascular Response Following Injection of Ganglion-Blocking Agents

Abstract
The reduction of arterial pressure in anesthetized dogs following the injection of ganglion-blocking agents is dependent primarily upon a reduction in arterial vasomotor activity and secondarily upon a reduction in venous return associated with an increase in vascular capacity. When venous return is maintained at control levels, the administration of the blocking agents of this study invariably produce a decrease in total peripheral resistance (TPR). Ordinarily in the intact animal such a decrease in TPR is not observed due to a marked reduction in cardiac output which produces a secondary increase in TPR. The results of this study further suggests that the venous and arterial systems may differ in their sensitivity to the effects of ganglion-blocking agents.