| In Vitro | In vitro activity: Risperidone binds to both DA and serotonin (5HT) receptors, particularly in the neurons of striatal and limbic structures. Risperidone significantly affects brain nerve growth factor (NGF) level suggesting that it influences the turnover of endogenous growth factors. Risperidone significantly decreases BDNF concentrations in frontal cortex, occipital cortex and hippocampus and decreases or increases TrkB receptors in selected brain structures. Risperidone significantly increases D(2) binding in medial prefrontal cortex by 34% in rat forebrain regions. Risperidone produces even greater up-regulation of D(4) receptors in CPu (37%), NAc (32%), and HIP (37%) in rat forebrain regions. Risperidone significantly inhibits the production of NO and proinflammatory cytokines by activated microglia. Risperidone (1-50 mM) significantly enhances the intracellular accumulation of Rh123 in Caco-2 cells by inhibiting P-gp activity with an IC(50) value of 5.87 mM. |
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| In Vivo | Risperidone does not significantly affect bodyweight gain (BWG), food intake(FI), glucose tolerance or leptin levels, even though prolactin and corticosterone are significantly elevated in male rats. Risperidone significantly increases BWG and FI in female rats. Risperidone (0.05 mg/kg) increases food intake and leptin gene expression in white adipose tissue (WAT), but the rate of bodyweight gain is not affected in rats. Risperidone (0.5 mg/kg) causes a reduction in bodyweight gain, as well as enhanced Ucp1 gene expression in BAT and serum prolactin concentrations in rats. |
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