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The effects of insulin on mesenteric blood flow in anaesthetized pigs
Author(s) -
Grossini E.,
Battaglia A.,
Bona G.,
Mary D. A. S. G.,
Molinari C.,
Vacca G.
Publication year - 2004
Publication title -
experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0958-0670
DOI - 10.1113/expphysiol.2004.027334
Subject(s) - phentolamine , vasodilation , insulin , medicine , endocrinology , vasoconstriction , mesenteric arteries , blood flow , nitric oxide , blood pressure , anesthesia , artery , stimulation
Infusion of insulin in anaesthetized pigs has been shown to cause an increase in renal blood flow and a decrease in coronary blood flow, which were the net result of a vasoconstriction involving sympathetic α‐adrenoceptor‐mediated mechanisms and of a local vasodilatation involving the endothelial release of nitric oxide. In the present study, the effect of insulin on superior mesenteric blood flow was examined in pentobarbitone‐anaesthetized pigs at constant heart rate, aortic blood pressure, left ventricular contractility and blood levels of glucose and potassium. In 10 pigs, infusion of 0.004 IU kg −1 min −1 of insulin increased mesenteric flow. In five of these pigs, intravenous phentolamine enhanced the increase in mesenteric flow elicited by insulin, a response which was abolished by the subsequent injection of N ω ‐nitro‐ l ‐arginine methyl ester ( l ‐NAME) into the mesenteric artery. In the remaining five pigs, infusion of insulin after intramesenteric injection of l ‐NAME caused a decrease in mesenteric flow. This response was abolished by the subsequent intravenous administration of phentolamine. The present study showed that infusion of insulin in anaesthetized pigs primarily caused a mesenteric vasodilatation, which was the net result of two opposite effects, namely a predominant vasodilatation mediated by the endothelial release of nitric oxide and a sympathetic vasoconstrictor mechanism mediated by α‐adrenoceptors.