These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Endothelin-induced contraction and relaxation of rat isolated basilar artery: effect of BQ-123.
    Author: Feger GI, Schilling L, Ehrenreich H, Wahl M.
    Journal: J Cereb Blood Flow Metab; 1994 Sep; 14(5):845-52. PubMed ID: 8063879.
    Abstract:
    In ring segments from rat basilar artery (BA) the endothelin (ET) peptides ET-1, ET-2, and ET-3 induced concentration-related contractions. The order of potency was ET-1 = ET-2 > ET-3, while no differences occurred in the maximum contraction. The selective ETA receptor antagonist, BQ-123 (10(-10)-10(-4) M) alone elicited a small contraction only at 10(-4) M. In the presence of BQ-123 (10(-7)-10(-5) M), the concentration-response curve for ET-1 was shifted to the right without any decrease in maximum contraction, indicating competitive inhibition of ET-1 binding to the ETA receptor by BQ-123. The pA2 value calculated for BQ-123 was 6.935; the slope of the regression curve was 0.734. In contrast to ET-1, the contractile action of ET-3 was abolished by 10(-5) M BQ-123. In segments precontracted with 10(-6) M serotonin, ET-3, but not ET-1, induced relaxation at low concentrations (10(-11)-10(-8) M), with maximum relaxation amounting to 17.8 +/- 14.7% of precontraction (mean +/- SD; n = 16). The relaxant action of ET-3 was abolished in vessels incubated with NG-nitro-L-arginine (10(-5) M), an inhibitor of nitric oxide synthase. These results indicate that the ET-induced contraction of the isolated rat BA involves activation of the ETA receptor. The ET-3-induced relaxation of precontracted rat BA is apparently mediated by release of nitric oxide from the endothelium.
    [Abstract] [Full Text] [Related] [New Search]