Effects of the ethanolic extract of Spirulina maxima on endothelium dependent vasomotor responses of rat aortic rings.
Dietary Spirulina decreases, endothelium-dependently, the responses to vasoconstrictor agonists and increases the endothelium-dependent, agonist-induced, vasodilator responses of rat aorta rings. The aim of this study was to analyze, in vitro, the effects of a raw ethanolic extract of Spirulina maxima on the vasomotor responses of rat aortic rings to phenylephrine and to carbachol. On rings with endothelium, the extract produced the following effects: (a) a concentration-dependent (60-1000 microg/ml) decrease of the contractile response to phenylephrine; (b) a rightward shift and a decrease in maximal developed tension, of the concentration--response curve to phenylephrine; (c) a concentration dependent relaxation of phenylephrine-precontracted rings. These effects were blocked by L-NAME, and not modified by indomethacin. The extract had no effect on the concentration-response curve to carbachol of rings with endothelium. On endothelium-denuded rings the extract caused a significant rightward shift of the concentration response curve to phenylephrine without any effect on maximal tension development. In the presence of the extract, indomethacin induced a marked decrease in the maximal phenylephrine-induced tension of endothelium-denuded rings. These results suggest that the extract increases the basal synthesis/release of NO by the endothelium and, also, the synthesis/release of a cyclooxygenase-dependent vasoconstricting prostanoid by vascular smooth muscle cells.
Paredes-Carbajal
M C
MC
Department of Physiology, School of Medicine, UNAM, P.O. Box 70-250, Mexico D.F. 04510, Mexico. cparedes@servidor.unam.mx
Torres-Durán
P V
PV
Díaz-Zagoya
J C
JC
Mascher
D
D
Juárez-Oropeza
M A
MA
D000818:Animals; D001011:Aorta / Q000187:drug effects* / Q000502:physiology; D001426:Bacterial Proteins / Q000187:drug effects*; D002217:Carbachol / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D010656:Phenylephrine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D053545:Spirulina
D001426:Bacterial Proteins; D010656:Phenylephrine; D002217:Carbachol