Article date: March 1991
By: Judith M. Hills, Madelene M. Larkin, William Howson, in Volume 102, Issue 3, pages 631-634
A series of GABAB receptor antagonists were tested against (±)‐baclofen for activity on the presynaptic GABAB receptor in the rat vas deferens.
All the antagonists tested caused a rightward shift in the concentration‐response curve to (±)‐baclofen.
pA2 values calculated from full Schild analysis were as follows: phaclofen, pA2 = 4.3; δ‐amino valeric acid, pA2 = 4.4; 3‐aminopropyl(diethoxymethyl)phosphinic acid (CGP 35348), pA2 = 5.0; 3‐aminopropyl(n‐hexyl)phosphinic acid (3‐APHPA), pA2 = 4.5.
These results show that none of the above compounds possess potent antagonist activity at the GABAB receptor (i.e. pA2 > 6) in this peripheral tissue. In addition, the more recently available phosphinic acid antagonists, appear to offer no great advance over the GABAB antagonists previously available.
A series of GABAB receptor antagonists were tested against (±)‐baclofen for activity on the presynaptic GABAB receptor in the rat vas deferens.
All the antagonists tested caused a rightward shift in the concentration‐response curve to (±)‐baclofen.
pA2 values calculated from full Schild analysis were as follows: phaclofen, pA2 = 4.3; δ‐amino valeric acid, pA2 = 4.4; 3‐aminopropyl(diethoxymethyl)phosphinic acid (CGP 35348), pA2 = 5.0; 3‐aminopropyl(n‐hexyl)phosphinic acid (3‐APHPA), pA2 = 4.5.
These results show that none of the above compounds possess potent antagonist activity at the GABAB receptor (i.e. pA2 > 6) in this peripheral tissue. In addition, the more recently available phosphinic acid antagonists, appear to offer no great advance over the GABAB antagonists previously available.
DOI: 10.1111/j.1476-5381.1991.tb12224.x
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