AbstractAlthough the psychotomimetic action of phencyclidine is often used to model a hypoglutamate theory of psychosis or schizophrenia, work also exists showing that phencyclidine has a significant affinity for the dopamine D2 receptor. The present study was done to determine whether phencyclidine has a direct functional dopamine‐like action on cells. The effect of phencyclidine was tested on the release of prolactin from rat cultured anterior pituitary cells. It was found that the release of prolactin was 50% inhibited by 4 nM phencyclidine. This strong dopamine‐like agonist action at the functional high‐affinity state of the dopamine D2 receptor by the phencyclidine psychotomimetic is consistent with the dopamine hypothesis of psychosis. Synapse 58:275–277, 2005. © 2005 Wiley‐Liss, Inc.