Effects of single and long-term administration of sulpiride on open-field and stereotyped behavior of rats

ABSTRACT

1. The effects of single (3.0 to 180.0 mg/Kg) and long-term (up to 90.1 mg/Kg) administration of sulpiride on open-field and apomorphine-induced stereotyped behavior of rats were studied. 2. when animals were studied 30 min after ip sulpiride administration and rearing frequencies in the open-field or apomorphine effects were not modified in a dose-dependent and consistentway by the single sulpiride administration. 3. In relation to control values, a significant decrease im apomorphine-induced stereotyped behavior was observed when rats were injected with a single sulpiride dose 2.5, 5.0, 7.5 and 10.0 h before the dopaminergic agonist. 4. Withdrawal from long-term ip sulpiride administration (up to 90.0 mg/Kg per injection, twice daily for 57 days) induced a significant increase in all parameters of activity recorded in the open-field, and the responsiveness to apomorphine was also augmented in sulpiride-withdrawn rats. 5. These results suggest that sulpiride, a benzamide drug that differs from classic neuroleptic agents by producing fewer extrapyramidal side effects, also supersensitivity of central dopaminergic receptors