Effects of the GABA receptor agonist muscimol on the turnover of brain dopamine and on the motor activity of rats.

Muscimol (3-hydroxy-5-aminomethylisoxazole) at a high dose (10 mg/kg intraperitoneally) elevated the concentration of brain dopamine in rats, decreased the utilization of dopamine and increased the synthesis of dopamine. The utilization of noradrenaline was acclerated rather than retarded by muscimol. Local application of muscimol to the nucleus accumbens of rats inhibited the motor activity in a dose-dependent manner with only a slight subsequent hyperactivity. The effects are similar to those produced by GABA and they support the view that muscimol is a GABA receptor agonist.