PCP acts on which receptor type?

• A. GABA_A receptor
• B. Dopamine D2 receptor
• C. NMDA glutamate receptor
• D. Serotonin 5-HT2A receptor

Answer: (C)

The main concept tested is how PCP exerts its effects at the receptor level. PCP acts primarily as a noncompetitive antagonist of the NMDA-type glutamate receptor. By blocking the NMDA receptor’s ion channel, PCP prevents calcium influx and reduces excitatory neurotransmission, even when glutamate is present. This disruption of glutamatergic signaling in brain circuits involved in perception, memory, and cognition produces the dissociative, analgesic, and psychotomimetic effects associated with PCP.

Other receptors listed do not explain PCP’s characteristic actions as well: GABA_A receptors mediate inhibitory GABAergic transmission and PCP’s effects aren’t due to potentiating this system; Dopamine D2 receptors relate more to classic antipsychotics’ actions and aren’t the primary mechanism for PCP’s dissociative effects; Serotonin 5-HT2A receptors are more linked to classic psychedelics’ psychedelic effects, not PCP’s main mechanism.