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Updated: Aug 15, 2026

Quantifying Agonist Activity at G Protein-coupled Receptors
Published on: December 26, 2011
Three putative 5-HT1A agonists act as 5-HT antagonists in frog sensory neurons
1Department of Pharmacology, University of Illinois, Medical College, Chicago 60612.
Abstract:
The putative 5-HT1A agonists 8-hydroxy-dipropylaminotetralin (DPAT), buspirone and p-aminophenylethyl-m-trifluoromethylphenyl piperazine (PAPP) were tested for their ability to narrow the action potentials of bullfrog sensory neurons, a serotonergic response observed to be blocked by the 5-HT1A antagonists spiperone and spiroxitrine. Given alone, DPAT, buspirone, and PAPP were ineffective 5-HT agonists. When applied concomitantly with 5-HT, however, they significantly antagonized the original response. Thus, in some systems these putative 5-HT1A agonists function as antagonists.
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