Extrasynaptic δ-GABAA receptors are high-affinity muscimol receptors.
Journal of neurochemistry April 1, 2019 Ali Y Benkherouf, Kaisa-Riitta Taina, Pratap Meera et al. 26 citations
Muscimol, the psychoactive compound from the Amanita muscaria mushroom, binds with high affinity to a specific subtype of GABAA receptors that contain the δ subunit. Deleting the δ subunit in mice eliminates more than 50% of high-affinity muscimol binding sites in the brain, even though δ-containing receptors are relatively scarce. Native δ-GABAA receptors in wild-type mice show binding affinities around 1–2 nM, and incorporating the δ subunit into recombinant receptors produces currents with slow deactivation and extreme sensitivity to muscimol. The findings indicate that δ subunit incorporation dramatically increases muscimol sensitivity, explaining low-dose selectivity for δ-containing receptors in biochemical and behavioral experiments.