Mechanism of interaction between neuropeptide Y and angiotensin II in the rabbit femoral artery.
Neuropeptide Y has direct vasoconstrictor actions and potentiates the effects of other vasoconstrictor agents. To find out whether both effects of neuropeptide Y are mediated via the same receptor and intracellular mechanism, the interaction between neuropeptide Y and angiotensin II was studied in rabbit femoral arteries. In this preparation, neuropeptide Y, but not its 13-36 fragment, induced constriction. Only neuropeptide Y potentiated the vasoconstrictor response to angiotensin II and the associated rise in inositol-1-phosphate. These potentiating effects of neuropeptide Y were totally prevented by removal of extracellular Ca2+, partially prevented by a Ca(2+)-channel blocker and mimicked by a Ca(2+)-channel activator. Pharmacological modulation of adenylate cyclase had no effect. These results suggest that the direct and indirect vascular effects of neuropeptide Y are mediated via Y1 receptors and depend on the influx of extracellular Ca2+. The rise in inositol-1-phosphate seems to be secondary to an increase in intracellular Ca2+, while modulation of adenylate cyclase is apparently not involved.
Cressier
F
F
Ciba-Geigy Ltd, Basel, Switzerland.
Criscione
L
L
Hofbauer
K G
KG
D000262:Adenylyl Cyclases / Q000378:metabolism; D000804:Angiotensin II / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D004357:Drug Synergism; D005263:Femoral Artery / Q000187:drug effects* / Q000378:metabolism; D007295:Inositol Phosphates / Q000378:metabolism; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009478:Neuropeptide Y / Q000378:metabolism / Q000494:pharmacology*; D011817:Rabbits; D013552:Swine; D014661:Vasoconstriction / Q000187:drug effects*
D002121:Calcium Channel Blockers; D007295:Inositol Phosphates; D009478:Neuropeptide Y; D000804:Angiotensin II; C002647:inositol 1-phosphate; D000262:Adenylyl Cyclases; D002118:Calcium