Anisatin modulation of GABA- and pentobarbital-induced enhancement of diazepam binding in rat brain

At a physiological temperature, anisatin may have a more potent modulatory effect on benzodiazepine-GABA receptor coupling, through the barbiturate-picrotoxin sensitive sites.

Abstract

Anisatin, a pure toxic substance isolated from the seeds of a Japanese plant (Illicium anisatum) acts as a picrotoxin-like, non-competitive GABA antagonist. Anisatin inhibited [3H]diazepam binding enhanced by either GABA or pentobarbital, without affecting the basal specific binding to rat brain membranes. The inhibition of this pentobarbital enhancement was competitive. These actions of anisatin were even more apparent when the binding assays were carried out at 37 degrees C rather than a 0 degrees C. Thus, at a physiological temperature, anisatin may have a more potent modulatory effect on benzodiazepine-GABA receptor coupling, through the barbiturate-picrotoxin sensitive sites.