title: Vasodilator effects of liriodenine and norushinsunine, two aporphine alkaloids isolated from Annona cherimolia, in rat aorta.
abstract: The effect of two aporphines, liriodenine and norushinsunine, isolated from Annona cherimolia, were studied in the rat aorta in order to examine their mechanism of action. Both alkaloids (10(-7) - 10(-4) mol/l) showed relaxant effects on the contractions elicited by 10(-6) mol/l noradrenaline (NA) or 80 mmol/1 KCl, but, while liriodenine showed a nonspecific relaxant action on both spasmogens, norushinsunine was more potent on KCl-induced contraction. In Ca2+ free medium, both alkaloids (0.1 mmol/l) inhibited the responses elicited by NA, but not those elicited by caffeine. This inhibitory action occurred when the alkaloids were present during the release of the Ca2+ internal stores or during the refilling process. These results suggest that the two aporphines show a relaxant action in rat aorta which is mediated by an interaction with alpha1-adrenoceptors and an alteration of the Ca2+ entry via voltage-operated channels. Norushinsunine exhibits a certain degree of selectivity as an L-type Ca2+ channel blocker.
authors.affiliation: Departamento de Farmacologia, Facultad de Farmacia, Universidad de Valencia, Burjasot/Valencia, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Chuliá
authors.forename: M A
authors.initials: MA
authors.lastname: Noguera
authors.forename: M D
authors.initials: MD
authors.lastname: Ivorra
authors.forename: D
authors.initials: D
authors.lastname: Cortes
authors.forename: M P
authors.initials: MP
authors.lastname: D'Ocón
mesh_terms: D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D001011:Aorta / Q000187:drug effects*; D001060:Aporphines / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D008297:Male; D010936:Plant Extracts / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D014664:Vasodilation / Q000187:drug effects*
chemical_list: D000470:Alkaloids; D001060:Aporphines; D010936:Plant Extracts; C081279:aporphine; C026980:liriodenine; D002118:Calcium