Agmatine: a novel endogenous vasodilator substance.
The purpose of the study was to investigate the effects of agmatine, an endogenous clonidine-displacing substance (CDS), on systemic hemodynamics in the anesthetized rat. Bolus intravenous (i.v.) injections of agmatine decreased systemic arterial pressure (SAP) and systemic vascular resistance in a dose-dependent manner. The development of acute tachyphylaxis to the systemic vasodepressor response to agmatine did not induce cross-tachyphylaxis to the systemic vasodepressor responses to bradykinin, isoproterenol and nitroglycerin. The present data demonstrate agmatine, as a CDS and agonist for imidazoline (I) receptors, possesses marked systemic vasodilator activity in the rat. The present data suggest that activation of I receptors may represent a novel mechanism of vasodilation in vivo.
Gao
Y
Y
Department of Surgery, Tulane University School of Medicine, New Orleans, LA 70112, USA.
Gumusel
B
B
Koves
G
G
Prasad
A
A
Hao
Q
Q
Hyman
A
A
Lippton
H
H
D000376:Agmatine / Q000494:pharmacology*; D000818:Animals; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013618:Tachyphylaxis; D014665:Vasodilator Agents / Q000494:pharmacology*
D014665:Vasodilator Agents; D000376:Agmatine