Lack of effect of an early stressful life event on sensorimotor gating in adult rats

Hypotheses of the etiology of schizophrenia emphasize the important role of perinatal insults in predisposing individuals to the development of the di sease, so that an animal model in which a discrete postnatal manipulation o f the infant social environment yields schizophrenia-like behavior in adult hood would be valuable in terms of the study of the neural substrate and tr eatment of schizophrenia. Schizophrenics demonstrate a deficit in sensorimo tor gating (prepulse inhibition), and a similar phenomenon has been describ ed in adult rats following the administration of direct and indirect dopami ne agonists. Recently it has been reported that a 24 h separation of rat pu ps from the mother results in a disruption of prepulse inhibition at adulth ood. Here we report a study which investigated the same phenomenon but whic h, in contrast to the previous study, utilized unrelated subjects all deriv ed from different dame. Maternal separation was conducted for 24 h with pup s aged 4, 9 or 18 days and these subjects, together with non-separated cont rols, were tested at age 3 months in terms of their prepulse inhibition in the acoustic startle response paradigm. Maternal separation did not disrupt prepulse inhibition. Comparison of males and females (with a maximum of on e opposite-sex sibling) demonstrated that acoustic startle response and pre pulse inhibition of this response was enhanced in males relative to females . This study indicates that 24 h maternal separation does not provide a rob ust model for studying the effects of early environmental insults on the lo ng-term abnormal development of sensorimotor gating. (C) 2000 Elsevier Scie nce B.V. All rights reserved.