Comparative study of the inhibitory effects of adrenomedullin on angiotensin II contraction in rat conductance and resistance arteries.
Adrenomedullin (ADM), a ubiquitous vasoactive peptide, has been the target of a multitude of studies concerning its effect on the vascular tone. The present work aims at clarifying a series of its interactions with the renin-angiotensin system. The study uses the rat aorta ring as a model of conductance vessels, with or without vascular endothelium, and the second order branch of rat mesenteric arteries as a model of resistance arteries. Interactions between various concentrations of ADM and angiotensin II (Ang II) were studied, in the presence of L-NAME (a nitric oxide [NO] synthase inhibitor) and methylene blue (MB; a soluble guanylate cyclase inhibitor). Results point out differences in the mechanism of the inhibitory action of ADM upon Ang II effects in the two vessel types studied. Inhibition of Ang II contraction by ADM involves guanylate cyclase in both cases. However, NO is involved in ADM-induced inhibition of angiotensinergic vasoconstriction only in the conductance arteries, not in the resistance ones.
Haulica
Ion
I
Laboratory of Experimental and Applied Physiology of the Romanian Academy. ihaulica@yahoo.com
Bild
Walther
W
Mihaila
Christian
C
Serban
Dragomir N
DN
Serban
Lacramioara
L
Boisteanu
Daniela
D
Ionita
Teodor
T
Radasanu
Oana
O
D053607:Adrenomedullin; D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects* / Q000502:physiology; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects* / Q000502:physiology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology*; D010656:Phenylephrine / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D014655:Vascular Resistance / Q000187:drug effects; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
D004791:Enzyme Inhibitors; D010455:Peptides; D014662:Vasoconstrictor Agents; D000804:Angiotensin II; D053607:Adrenomedullin; D010656:Phenylephrine; D011188:Potassium; D019331:NG-Nitroarginine Methyl Ester