Mesoridazine is a dopaminergic antagonist, with a Kd value of 19 nM for the dopamine D2 receptor. Mesoridazine is an active metabolite of the atypical antipsychotic drug thioridazine, exhibiting stronger inhibition on pre- and postsynaptic dopamine receptors which modulate dopamine and acetylcholine release. Thus, mesoridazine is responsible for a significant part of the antidopaminergic effects attributed to thioridazine. In addition, mesoridazine also binds to histamine H1, muscarinic acetylcholine, as well as α1- and α2-adrenergic receptors, with Kd values being 1.8, 69, 2 and 1600 nM, respectively.
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