Endothelin enhances adrenergic vasoconstriction in perfused rat mesenteric arteries.
The interaction of endothelin with alpha-adrenergic receptors was examined in isolated perfused rat mesenteric arteries. Infusion of porcine or rat endothelin increased the baseline perfusion pressure dose-dependently. Subpressor doses of both porcine (10(-11) and 10(-10)M) and rat (10(-10) and 10(-9)M) endothelin enhanced the pressor responses to norepinephrine. Nicardipine (10(-7)M), a calcium channel blocker, attenuated this potentiation. These results suggest that endothelin enhances the responsiveness of alpha-adrenergic receptors to catecholamines probably through the increase in calcium influx. Thus endothelin may interact with sympathetic nerve activity in addition to having a direct vasoconstrictor action in peripheral vascular tissue.
Tabuchi
Y
Y
Department of Geriatric Medicine, Osaka University Medical School, Japan.
Nakamaru
M
M
Rakugi
H
H
Nagano
M
M
Ogihara
T
T
D000818:Animals; D016232:Endothelins; D004727:Endothelium / Q000502:physiology*; D066298:In Vitro Techniques; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects / Q000502:physiology*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D009529:Nicardipine / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology*; D010455:Peptides / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000502:physiology*; D012016:Reference Values; D013552:Swine; D014661:Vasoconstriction / Q000187:drug effects*
D016232:Endothelins; D010455:Peptides; D011942:Receptors, Adrenergic, alpha; D009529:Nicardipine; D009638:Norepinephrine