Trifluoperazine (TFP) is a phenothiazine compound with anti-adrenergic and anti-dopaminergic actions typical of antipsychotic agents. It antagonizes adrenergic receptors, with selectivity for α1 over the α2 subtypes (Kis = 24, 653, 163, and 391 nM for α1A, α2A, α2B, and α2C, respectively). TFP binds with much higher affinity to the dopamine D2-like receptor (Kd = 0.96 nM) compared to the dopamine D4-like and the serotonin 5-HT2A receptors (Kds = 44 and 135 nM, respectively). Furthermore, TFP antagonizes calmodulin (CaM) and alters the calcium-binding properties of calsequestrin (CSQ). TFP has been shown to activate type-2 ryanodine receptors independently of its CaM and CSQ activity.
