Increased peripheral α₁-adrenoceptor sensitivity following chronic thioridazine treatment in the pithed rat

The effect of chronic treatment (10 days) with thioridazine (25 mg/kg per day, i.p.) on the increase in diastolic blood pressure induced by methoxamine and xylazine was studied in the pithed rat. The dose-response curve for methoxamine, but not for xylazine, was shifted to the left by the neuroleptic. These results indicate that postjunctional α1-adrenoceptors in the rat blood vessels become supersentitive after long-term treatment with thioridazine. © 1989.