Comparison of Changes in Mesenteric Resistance Following Splanchnic Nerve Stimulation with Responses to Epinephrine and Norepinephrine

Abstract

This is a study of the characteristics of the splanchnic nerve supply to the mesenteric vascular circuit. The flow and pressure responses in the dog's superior mesenteric artery to splanchnic nerve stimulation and to intraarterial injections of epinephrine and norepinephrine, before and during various levels of adrenergic blockade, are analyzed. The results suggest that the splanchnic nerve contains only vasoconstrictor fibers, the mediator of which is probably norepinephrine, but that it also contains fibers which induce the release of epinephrine from the adrenal gland. No evidence for the presence of cholinergic dilator fibers was found.