Influence of urocortin and corticotropin releasing factor on venous tone in conscious rats.
The corticotropin releasing factor (CRF) family includes CRF and urocortin. The effects of urocortin and CRF (0.3, 1, 3 and 10 nmol/kg, i.v.) relative to those of vehicle (0.9% NaCl) on mean arterial pressure and mean circulatory filling pressure (index of venous tone) were examined in conscious, unrestrained rats that were either intact (unblocked) or ganglion-blocked by treatment with mecamylamine (10 mg/kg, i.v.) followed by noradrenaline (4 microg/kg/min, i.v.) to increase vasomotor tone. Both urocortin and CRF dose-dependently decreased mean arterial pressure in intact rats and ganglion-blocked rats. The depressor action of urocortin was greater than that of CRF at all doses. In intact rats, neither compound reduced mean circulatory filling pressure. In ganglion-blocked rats, urocortin and the highest dose of CRF decreased mean circulatory filling pressure. In conclusion, both urocortin and CRF are vasodepressor agents with venodilator action.
Abdelrahman
Aly M
AM
Department of Pharmacology and Therapeutics, Faculty of Medicine, The University of British Columbia, 2176 Health Sciences Mall, Vancouver, B.C., Canada V6T 1Z3.
Lin Lim
Su
S
Pang
Catherine C Y
CC
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D003243:Consciousness; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005730:Ganglionic Blockers / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D008464:Mecamylamine / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D054832:Urocortins; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014690:Venous Pressure / Q000187:drug effects*
D005730:Ganglionic Blockers; D054832:Urocortins; D014662:Vasoconstrictor Agents; D008464:Mecamylamine; D003346:Corticotropin-Releasing Hormone; D009638:Norepinephrine