Figure 1. Schematic of the effect of CPZ on dopaminergic neurotransmission.

(A) Chemical structure of CPZ. (B) In the absence of CPZ, release of dopamine from presynaptic terminals activates postsynaptic dopamine receptors, including D2, initiating downstream signal transduction (left side, blue). CPZ binds to D2 receptors without activating them. This prevents dopamine from binding to D2 receptors and blocks downstream signal transduction (right side, green).