PMID: 8960382Aug 1, 1996Paper

Differentiation of binding sites of CGP12177, a beta 3-adrenoceptor partial agonist, and carteolol, a beta 1/beta 2-adrenoceptor partial agonist, to the beta-adrenoceptors in guinea-pig taenia caecum

Canadian Journal of Physiology and Pharmacology
K KoikeM Yamazaki

Abstract

Differentiation of binding sites of CGP12177 and carteolol to the beta-adrenoceptors in the guinea-pig taenia caecum was investigated. Carteolol and CGP12177 competitively antagonized the relaxation responses to isoprenaline, and the pA2 values were 9.87 and 9.33, respectively. Butoxamine, a beta 2-selective antagonist, caused competitive antagonism of the relaxant responses to carteolol, and the pA2 value for butoxamine was 6.22. However, butoxamine (10(-4) M) did not significantly affect the relaxant responses to CGP12177. CGP12177 caused competitive antagonism of the relaxant responses to carteolol, and the pA2 value for CGP12177 was 9.32. However, carteolol (10(-6) M) did not significantly affect the relaxant responses to CGP12177. The competitive inhibition curve for specific binding of 50 nM [3H]befunolol by carteolol showed a biphasic shape, although the curve by CGP12177 was monophasic. Moreover, the competitive inhibition curve for specific binding of 100 nM [3H]CGP12177 by CGP12177 showed a biphasic shape, although the curve by carteolol indicated partial inhibition. These results suggest that the low affinity site of beta-adrenoceptor and beta 3-adrenoceptors are different from each other.

Citations

Feb 13, 2001·British Journal of Pharmacology·D S HutchinsonR J Summers
Sep 19, 2006·American Journal of Respiratory Cell and Molecular Biology·Robert H MooreRichard B Clark
Jan 4, 2001·Japanese Journal of Pharmacology·T Horinouchi, K Koike
Mar 16, 2018·Journal of Smooth Muscle Research = Nihon Heikatsukin Gakkai Kikanshi·Daisuke ChinoYoshio Tanaka

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