Effect of intermedin/adrenomedullin-2 on venous tone in conscious rats.
We investigated the effect of intermedin/adrenomedullin-2 (3 and 10 nmol/kg, i.v.), a member of the calcitonin gene-related peptide family, relative to the vehicle (0.9% NaCl) on mean circulatory filling pressure (index of venous tone) in conscious rats: intact (unblocked) or ganglionic blocked through treatment with mecamylamine (10 mg/kg, i.v.) and noradrenaline (4 microg/kg/min, i.v.). In intact rats, both doses of intermedin/adrenomedullin-2 reduced mean arterial pressure (-14+/-3, -30+/-3 mmHg), but did not alter mean circulatory filling pressure; the high dose also increased heart rate. In ganglionic-blocked rats, both doses decreased mean arterial pressure (-22+/-3, -46+/-5 mmHg) and the high dose also decreased mean circulatory filling pressure (-2.81+/-0.82 mmHg), but neither dose affected heart rate. The vehicle did not have any effects in any of the groups. In addition, intermedin/adrenomedullin-2 did not have any effect on blood volume in both intact and ganglion-blocked rats. The results show that intermedin/adrenomedullin-2 is a dilator of arterial resistance and capacitance vessels.
Abdelrahman
Aly M
AM
Department of Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia, 2176 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada.
Pang
Catherine C Y
CC
D053607:Adrenomedullin / Q000494:pharmacology / Q000502:physiology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001810:Blood Volume / Q000187:drug effects; D002496:Central Venous Pressure / Q000187:drug effects; D005730:Ganglionic Blockers / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D008464:Mecamylamine / Q000494:pharmacology; D009479:Neuropeptides / Q000494:pharmacology / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D018924:Vascular Capacitance; D014655:Vascular Resistance; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014680:Veins / Q000187:drug effects / Q000502:physiology*
C499411:Adm2 protein, rat; D005730:Ganglionic Blockers; D009479:Neuropeptides; D014662:Vasoconstrictor Agents; D053607:Adrenomedullin; D008464:Mecamylamine; D009638:Norepinephrine