To determine if the antagonism of serotonin 5HT(2A) receptors and dopamine D2 receptors by risperidone alters the mRNAs encoding the transporters and enzymes that are involved in re-uptake of serotonin and dopamine and in the degradation and refilling of secretory vesicles, we employed semi-quantitative RT-PCR on rats given risperidone. The rats were given twice daily a subcutaneous injection of either 0.3% tartaric acid (vehicle) or risperidone (0.5 mg/kg) for 21 days and sacrificed one hour after the last injection. Risperidone enhanced the level of monoamine oxidase type B (MAO-B) mRNA in the brainstem (P < 0.05) and that of vesicular monoamine transporter-2 (VMAT2) mRNA in the hypothalamus (P < 0.05) when these levels were compared with the control ones, whereas there were no significant group differences in other mRNAs examined. The antagonism of 5HT(2A) and D2 receptors may thus affect the monoamine levels by regulating mRNAs encoding MAO-B and VMAT2.
|Number of pages||20|
|Publication status||Published - 01-01-1999|
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