Clozapine pre-treatment enhances raclopride catalepsy. |
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Authors: | M L Wadenberg P Seeman |
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Institution: | Department of Psychiatry, University of Toronto, Canada. |
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Abstract: | The clinical replacement of clozapine by another antipsychotic sometimes causes extrapyramidal signs, including dystonia, to appear suddenly. The present study was done, therefore, to test whether clozapine pre-treatment of rats could affect raclopride-induced catalepsy. Clozapine, at 5 mg/kg, given 2 h before a catalepsy-threshold dose of 0.1 mg/kg raclopride, markedly enhanced raclopride-induced catalepsy in the rats. The results are compatible with earlier in vitro data where pre-exposure of human cloned dopamine D2 receptors to clozapine resulted in an increased potency of raclopride in inhibiting the binding of 3H]clozapine to the receptors. The mechanism of clozapine potentiation of raclopride action may contribute to the clinically observed post-clozapine dystonia. |
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