Evidence exists that schizophrenia is characterized by deficits in cell-cell communication and information processing. In the present study, we used the phencyclidine (PCP) animal model of schizophrenia to investigate possible defects in intracellular signaling proteins involved in neuroplasticity. Western Blot analysis has been performed to determine total and phospho-protein levels of extracellular signal-regulated kinases 1/2 (ERK1/2), type II calcium/calmodulin-dependent protein kinase (alphaCaMKII) and cAMP-response element binding protein (CREB) in prefrontal cortex (PFC) and hippocampus (HIP) of rat chronically treated with PCP, whereas their mRNA levels were determined by real time RT-PCR. We found reduced levels of P-ERK1/2, P-alphaCaMKII and P-CREB in prefrontal cortex of PCP-treated animals when compared to controls, whereas no effects were observed on total protein or mRNA levels. Conversely, no significant changes were detected on protein levels or mRNA expression in hippocampus. Given the role of ERK1/2, alphaCaMKII and CREB in neuroplastic mechanisms and cell communication, our data suggest that their decreased activation following chronic PCP administration can contribute to cortical defects occurring in schizophrenia, and may therefore represent potential targets for pharmacological intervention.