Blood flow alteration induced by saralasin or SNP

In rats, the decrease in blood pressure with each drug treatment was due to a change in peripheral resistance rather than a change in cardiac output. The maintenance of normal blood pressure by a compensatory increase in cardiac output is prevented by depression of the myocardium by halothane and/or a decrease in venous return secondary to venous dilatation. Saralasin resulted in a small decrease in splanchnic blood flow which is known to occur with other agents which tend to lower blood pressure. However, sodium nitroprusside (SNP) resulted in an overall increase in splanchnic blood flow. In contrast to saralasin, renal blood flow decreased with SNP. This study suggests that saralasin and perhaps other angiotensin antagonists may lower blood pressure in anesthetized patients with preservation of renal blood flow. SNP in our model decreased renal blood flow but improved splanchnic blood flow. Certain patients may benefit from the selective effects of either agent.