The effects of phencyclidine on glutamic acid decarboxylase activity in several regions of the rat brain.

Glutamic acid decarboxylase (GAD) activity in several regions of the rat brain were monitored after administration of phencyclidine. Sub-acute (4 injections over 12 h) treatment decreased cerebellar GAD activity 6 and 12 h after the last dose; recovery was noticed by 24 h. This effect occurred with doses of 5 and 10 mg/kg. GAD activity in other brain regions was not affected by this treatment. Acute and chronic treatments with phencyclidine caused no change in GAD activity in any of the brain regions examined.