ESTRADIOL CAN SUPPRESS HALOPERIDOL-INDUCED SUPERSENSITIVITY IN DYSKINETIC MONKEYS

We have studied a monkey model of lingual dyskinesia, due to a midbrain lesion, which is markedly increased by apomorphine. In such animals a single large intramuscular dose of haloperidol (HAL), 1 mg/kg, almost completely abolishes the apomorphine potentiation after 24 h, but 15 days later there is a 5-fold increase in the response to apomorphine which we attribute to supersensitivity. Estradiol benzoate (0.15 mg/kg, subcutaneously) on days 3, 6, 9 and 12 after HAL completely suppresses the expected rebound supersensitivity to apomorphine. However, the suppression is not seen if the animals have received HAL and estradiol together in the initial treatment.