Open AccessA trial for kinetic evaluation of the antagonistic potency of several .BETA.-antagonists on presynaptic .BETA.-adrenoceptors.
Author(s) -
Misako Kuwahara,
Hiro Amano,
Takao Kubo,
Yoshimi Misu
Publication year - 1987
Publication title -
japanese journal of pharmacology/japanese journal of pharmacology
Language(s) - English
Resource type - Journals
eISSN - 1347-3506
pISSN - 0021-5198
DOI - 10.1254/jjp.43.445
Subject(s) - pindolol , potency , propranolol , pharmacology , beta (programming language) , stimulation , chemistry , nadolol , medicine , endocrinology , in vitro , biochemistry , computer science , programming language
The antagonistic potency, pA2, of several non-selective beta-antagonists on presynaptic beta-adrenoceptors was evaluated using a parallel line assay and MacKay's equation against isoproterenol-induced increases in 3H release in isolated guinea-pig pulmonary arteries preloaded with 3H-norepinephrine. Cumulatively applied isoproterenol at 10(-9) M, 10(-8) M and 10(-7) M dose-dependently increased 3H release evoked by transmural field stimulation at 1 Hz. beta-Antagonists tested dose-dependently antagonized the isoproterenol-induced increases. The order of pA2 was carteolol (11.23 +/- 0.09) greater than nadolol (9.78 +/- 0.05) greater than pindolol (9.59 +/- 0.03) greater than propranolol (9.26 +/- 0.17). Carteolol has the highest pA2 and is a useful tool for clarifying whether or not presynaptic beta-adrenoceptors tonically function.