PCP-based mice models of schizophrenia: differential behavioral, neurochemical and cellular effects of acute and subchronic treatments

Rationale N-methyl-D-aspartate receptor (NMDA-R) hypofunction has been proposed to account for the pathophysiology of schizophrenia. Thus, NMDA-R blockade has been used to model schizophrenia in experimental animals. Acute and repeated treatments have been successfully tested; however, long-term exposure toNMDA-R antagonists more likely resembles the core symptoms of the illness. Objectives To explore whether schizophrenia-related behaviors are differentially induced by acute and subchronic phencyclidine (PCP) treatment in mice and to examine the neurobiological bases of these differences. Results Subchronic PCP induced a sensitization of acute locomotor effects. Spontaneous alternation in a T-maze and novel object recognition performance were impaired after subchronic but not acute PCP, suggesting a deficit in working memory. On the contrary, reversal learning and immobility in the tail suspension test were unaffected. Subchronic PCP significantly reduced basal dopamine but not serotonin output in medial prefrontal cortex (mPFC) and markedly decreased the expression of tyrosine hydroxylase in the ventral tegmental area. Finally, acute and subchronic PCP treatments evoked a different pattern of c-fos expression. At 1 h post-treatment, acute PCP increased c-fos expression in many cortical regions, striatum, thalamus, hippocampus, and dorsal raphe. However, the increased c-fos expression produced by subchronic PCP was restricted to the retrosplenial cortex, thalamus, hippocampus, and supramammillary nucleus. Four days after the last PCP injection, c-fos expression was still increased in the hippocampus of subchronic PCP-treated mice. Conclusions Acute and subchronic PCP administration differently affects neuronal activity in brain regions relevant to schizophrenia, which could account for their different behavioral effectsThis work has received support from the Instituto de Salud Carlos III, Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM (13INT4 intramural project), and the Innovative Medicine Initiative Joint Undertaking under grant agreement no. 115008 of which resources are composed of EFPIA in-kind contribution and financial contribution from the European Union’s Seventh Framework Programme (FP7/2007-2013)Peer Reviewe