title: Endothelium-dependent relaxations of rabbit isolated aorta produced by carbachol and by Ginkgo biloba extract.
abstract: Spirally-cut strips of rabbit aorta were used to examine the relaxations produced by carbachol and extract of Ginkgo biloba (Gb) under isometric conditions. After precontracting the strips with phenylephrine (10(-7) M), carbachol produced a dose-related relaxation (PD2 congruent to 6.2 +/- 0.1) and this effect was antagonized competitively by atropine (PA2 congruent to 9.4 +/- 0.1). Gb (0.2 or 0.3 mg/ml) also relaxed the strips. Removal of the endothelium or a 30-min pre-treatment of the strips with a substance that has lipoxygenase-inhibitor activity (nordihydroguaiaretic acid, NDGA, 10(-5) M) abolished the relaxant effect of carbachol and partially blocked the relaxant effect of Gb. Thus, at least part of the relaxant effect of Gb is mediated by a factor(s) (e.g., EDRF) that is released from endothelial cells.
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001013:Aorta, Thoracic / Q000187:drug effects / Q000502:physiology*; D001285:Atropine / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology*; D002396:Catechols / Q000494:pharmacology; D004727:Endothelium / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D007537:Isometric Contraction / Q000187:drug effects; D008297:Male; D009637:Masoprocol; D009119:Muscle Contraction / Q000187:drug effects*; D009126:Muscle Relaxation / Q000187:drug effects*; D010656:Phenylephrine / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology*; D010946:Plants, Medicinal; D011817:Rabbits
chemical_list: D000975:Antioxidants; D002396:Catechols; D010936:Plant Extracts; D010656:Phenylephrine; D009637:Masoprocol; D001285:Atropine; D002217:Carbachol