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A comparison of the relative activities of a number of GABA B antagonists in the isolated vas deferens of the rat
Author(s) -
Hills Judith M.,
Larkin Madelene M.,
Howson William
Publication year - 1991
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1991.tb12224.x
Subject(s) - vas deferens , baclofen , antagonist , gaba receptor antagonist , chemistry , gabab receptor , medicine , gabaa receptor , pharmacology , endocrinology , receptor , bicuculline , biology , agonist
1 A series of GABA B receptor antagonists were tested against (±)‐baclofen for activity on the presynaptic GABA B receptor in the rat vas deferens. 2 All the antagonists tested caused a rightward shift in the concentration‐response curve to (±)‐baclofen. 3 pA 2 values calculated from full Schild analysis were as follows: phaclofen, pA 2 = 4.3; δ‐amino valeric acid, pA 2 = 4.4; 3‐aminopropyl(diethoxymethyl)phosphinic acid (CGP 35348), pA 2 = 5.0; 3‐aminopropyl(n‐hexyl)phosphinic acid (3‐APHPA), pA 2 = 4.5. 4 These results show that none of the above compounds possess potent antagonist activity at the GABA B receptor (i.e. pA 2 > 6) in this peripheral tissue. In addition, the more recently available phosphinic acid antagonists, appear to offer no great advance over the GABA B antagonists previously available.