| In Vitro | In vitro activity: Aripiprazole binds with high affinity to both the G protein-coupled and uncoupled states of receptors. Aripiprazole potently activates D2 receptor-mediated inhibition of cAMP accumulation. Aripiprazole has highest affinity for h5-HT(2B)-, hD(2L)-, and hD(3)-dopamine receptors, but also has significant affinity (5-30 nM) for several other 5-HT receptors (5-HT(1A), 5-HT(2A), 5-HT(7)), as well as alpha(1A)-adrenergic and hH(1)-histamine receptors. Aripiprazole has less affinity (30-200 nM) for other G protein-coupled receptors, including the 5-HT(1D), 5-HT(2C), alpha(1B)-, alpha(2A)-, alpha(2B)-, alpha(2C)-, beta(1)-, and beta(2)-adrenergic, and H(3)-histamine receptors. Aripiprazole is an inverse agonist at 5-HT(2B) receptors and displays partial agonist actions at 5-HT(2A), 5-HT(2C), D(3), and D(4) receptors. |
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| In Vivo | Aripiprazole reduces extracellular 5-HIAA concentrations in the medial prefrontal cortex and striatum of drug-naive rats, but not in chronic Aripiprazole-pretreated rats. Aripiprazole, 0.1 mg/kg and 0.3 mg/kg, significantly increases dopamine release in the hippocampus of rats. Aripiprazole, 0.3 mg/kg, slightly but significantly increases dopamine release in the medial prefrontal cortex but not in the nucleus accumbens. Aripiprazole, 3.0 mg/kg and 10 mg/kg, significantly decreases dopamine release in the nucleus accumbens but not the medical prefrontal cortex. Aripiprazole, 0.3 mg/kg, transiently potentiates haloperidol (0.1 mg/kg)-induced dopamine release in the medial prefrontal cortex but inhibited that in the nucleus accumbens. |
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