Regional haemodynamic effects of urocortin in the anaesthetized rat.
Urocortin is an endogenous vasodilator peptide that is related to corticotrophin-releasing factor. We examined the haemodynamic effects of urocortin in thiobutabarbital-anaesthetized rats, via the triple-isotope microspheres technique. Urocortin (3 nmol/kg, i.v. bolus) reduced mean arterial pressure (-25 mm Hg) through a decrease in total peripheral resistance (-43%). This was associated with an increase in cardiac output (+24%) and vasodilatation of the following tissues: heart and stomach (approximately 300% of baseline); liver, intestine, caecum/colon, skeletal muscle and skin (approximately 200%); and testes (approximately 150%). Arterial conductances of the kidneys, spleen and brain were unaffected by urocortin. Neither the vehicle (0.9% NaCl) nor a low dose of urocortin (0.3 nmol/kg) altered any measurements. Therefore, urocortin causes generalized vasodilatation as follows: heart and stomach>liver, intestine, caecum/colon, skeletal muscle and skin>testes.
Abdelrahman
Aly M
AM
Department of Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia, 2176 Health Sciences Mall, Vancouver, B.C., Canada V6T 1Z3.
Pang
Catherine C Y
CC
D000758:Anesthesia; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001921:Brain / Q000098:blood supply; D002302:Cardiac Output / Q000187:drug effects; D002432:Cecum / Q000098:blood supply; D003106:Colon / Q000098:blood supply; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D007275:Injections, Intravenous; D007668:Kidney / Q000098:blood supply; D008099:Liver / Q000098:blood supply; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply; D018696:Neuroprotective Agents / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow / Q000187:drug effects; D012867:Skin / Q000098:blood supply; D013154:Spleen / Q000098:blood supply; D013270:Stomach / Q000098:blood supply; D054832:Urocortins; D014655:Vascular Resistance / Q000187:drug effects
D018696:Neuroprotective Agents; D054832:Urocortins; D003346:Corticotropin-Releasing Hormone