title: Endothelium-dependent relaxation in perforating branch of human internal mammary artery.
abstract: The purpose of the present study was to examine the effect of acetylcholine on perforating branch of the human internal mammary artery (HIMA). Acetylcholine (10(-9)-10(-5)M) induced concentration- and endothelium-dependent relaxation (pEC(50)=7.54+/-0.03, maximal response was 98+/-1.3%) of the precontracted arterial segments. Indomethacin, 4-aminopyridine (10(-5)M) and precontraction with K(+)-rich Krebs-Ringer-bicarbonate solution had no effect on acethylcholine-induced relaxation. N(G)-monomethyl-L-arginine (L-NMMA) (10(-5)M) inhibited relaxation evoked by acetylcholine. Indomethacin applied together with L-NMMA lead to further inhibition of acethylcholine-induced relaxation. Even in the presence of both L-NMMA and indomethacin, 4-aminopyridine had no provoked further inhibition of acetylcholine-induced relaxation of perforating branch of HIMA. It was concluded that the acethylcholine-induced relaxation of isolated perforating branch of HIMA is probably mediated via endothelial production of nitric oxide. However, when NO-synthase is inhibited, acetylcholine-induced vasorelaxation may be, in part, mediated through activation of cyclooxygenase pathway and consequent production and release of prostacyclin or some other cyclooxygenase products.
authors.affiliation: Department of Pharmacology, Medical Faculty, Braće Tasković 81, 18000, Nis-YU, Yugoslavia.
authors.forename: S
authors.initials: S
authors.lastname: Pesić
authors.forename: A
authors.initials: A
authors.lastname: Jovanović
authors.forename: L
authors.initials: L
authors.lastname: Grbović
authors.forename: M
authors.initials: M
authors.lastname: Inić
authors.forename: N
authors.initials: N
authors.lastname: Munjas
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006801:Humans; D008323:Mammary Arteries / Q000502:physiology*; D008875:Middle Aged; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D014665:Vasodilator Agents; D000109:Acetylcholine