Phencyclidine animal models of schizophrenia: approaches from abnormality of glutamatergic neurotransmission and neurodevelopment.

Phencyclidine (PCP), a drug that blocks NMDA receptors, produces schizophrenia-like symptoms in humans, including positive symptoms, negative symptoms, and cognitive problems. This supports the glutamatergic dysfunction hypothesis of schizophrenia. Adult rodents given repeated PCP show hyperlocomotion (positive symptoms), social deficits, increased immobility (negative symptoms), sensorimotor gating problems, and cognitive impairments; some changes persist after withdrawal. Repeated PCP also causes neurochemical and neuroanatomical changes. Exposure to viral or environmental insults during the second trimester of pregnancy raises schizophrenia risk. Perinatal PCP treatment impairs neuronal development and leads to long-lasting schizophrenia-like behaviors in adulthood. These animal models are useful for testing treatments and studying schizophrenia's mechanisms.

Study at a glance

Abstract

In humans, phencyclidine (PCP), a non-competitive N-methyl-d-aspartate (NMDA) receptor antagonist, reproduces a schizophrenia-like psychosis including positive symptoms, negative symptoms and cognitive dysfunction. Thus, the glutamatergic neuronal dysfunction hypothesis is one of the main explanatory hypotheses and PCP-treated animals have been utilized as an animal model of schizophrenia. The adult rodents treated with PCP repeatedly exhibit hyperlocomotion as an index of positive symptoms, a social behavioral deficit in a social interaction test and enhanced immobility in a forced swimming test as indices of negative symptoms. They also show a sensorimotor gating deficits and cognitive dysfunctions in several learning and memory tests. Some of these behavioral changes endure after withdrawal from repeated PCP treatment. Furthermore, repeated PCP treatment induces some neurochemical and neuroanatomical changes. On the other hand, the exposure to viral or environmental insult in the second trimester of pregnancy increases the probability of subsequently developing schizophrenia as an adult. NMDA receptor has been implicated in controlling the structure and plasticity of developing brain circuitry. Based on neurodevelopment hypothesis of schizophrenia, schizophrenia model rats treated with PCP at the perinatal stage is developed. Perinatal PCP treatment impairs neuronal development and induces long-lasting schizophrenia-like behaviors in adult period. Many findings suggest that these PCP animal models would be useful for evaluating novel therapeutic candidates and for confirming pathological mechanisms of schizophrenia.