4-AHP

4-AHP, also known as 4--1-hydroxypyrazole, is a synthetic GABA_A receptor agonist related to the alkaloid and Amanita muscaria constituent muscimol.

Pharmacology

The drug is a moderately potent and high-efficacy partial to full agonist of the GABA_A receptor. It is less potent as a GABA_A receptor agonist than γ-aminobutyric acid, muscimol, or gaboxadol , but shows a similar functional activity profile relative to those of GABA and muscimol. The drug is also a high-efficacy partial agonist of the GABA_A-ρ receptor. It does not appear to have been evaluated in animals and its effects are unknown. 4-AHP is a close analogue of muscimol, in which the isoxazole ring has been replaced with a pyrazole ring.

4-AHP was first described in the scientific literature by 2013. It is one of only a few known analogues of muscimol that have been found to act as high-efficacy GABA_A receptor agonists, along with other related compounds such as dihydromuscimol, thiomuscimol, and gaboxadol. This can be attributed to the very strict structural requirements for GABA_A receptor binding and activation. A number of derivatives of 4-AHP have been synthesized and studied as GABA_A receptor ligands.