Variable maternal stress in rats alters locomotor activity, social behavior, and recognition memory in the adult offspring.

Rats repeatedly exposed to variable prenatal stress (PNS) exhibit behavioral signs that are similar to those manifested in several neuropsychiatric disorders such as deficits in attention and inhibitory control, and impairments in memory-related task performance. The purpose of the study described here was to conduct a comprehensive battery of tests to further characterize the behavioral phenotype of PNS rats as well as to evaluate the sensitivity of the model to therapeutic interventions (i.e., to compounds previously shown to have therapeutic potential in neuropsychiatric disorders). The results of this study indicated that PNS in rats is associated with: 1) increased locomotor activity and stereotypic behaviors, 2) elevated sensitivity to the psychostimulant amphetamine, 3) increased aggressive behaviors toward both adult and juvenile rats and 4) delay-dependent deficits in recognition memory. There was no evidence that PNS rats exhibited deficits in other areas of motor function/learning, sensorimotor gating, spatial learning and memory, social withdrawal, or anhedonia. In addition, the results revealed that the second generation antipsychotic risperidone attenuated amphetamine-related increases in locomotor activity in PNS rats; however, the effect was not sustained over time. Furthermore, deficits in recognition memory in PNS rats were attenuated by the norepinephrine reuptake inhibitor, atomoxetine, but not by the α7 nicotinic acetylcholine receptor partial agonist, GTS-21. This study supports the supposition that important phenomenological similarities exist between rats exposed to PNS and patients afflicted with neuropsychiatric disorders thus further establishing the face validity of the model for evaluating potential therapeutic interventions.