09152-2 and [3H]-7-OH-DPAT as radioligands to measure specific binding for D1, D2 and D3 receptors, respectively. The sections were exposed to [3H]Hyperfilm and analyzed using an image analysis system (MCID). Results: We found a significant increase in the number of mature neurons in the hippocampus CA1 region in both pre and postpubertal ages (P35 and P60) in the prenatal LPS treated offspring compared to the saline-treated animals. In the PFC, the number of mature neurons was comparable between LPS and saline group. The volumes of the regions of interest were not also significantly affected by the prenatal LPS treatment. In regard to dopaminergic receptors, we observed a significant decrease in the level of D2 receptor in PFC at both pre and post pubertal ages whereas no significant changes were observed in the striatum, nucleus accumbens shell and core regions. The expression of D1 and D3 receptors were not significantly different between prenatal LPS and saline treated offspring in all the regions of interest. Discussion: The significant increase in number of mature neurons can potentially impair the normal wiring and connectivity between CA1 region and its efferent regions such as the PFC and nucleus accumbens. Hippocampal-prefrontal-striatal circuits plays an im- portant role in dopaminergic activity and aberration within this circuit is well recognized in schizophrenia as well as certain neurodevelopmental animal models (e.g., neonatal ventral hippo- campus lesion). It is possible that significant decrease in prefrontal D2 receptor and impaired dopamine dependent behaviors may be related with this inappropriate connectivity due to increased number of neurons in the hippocampus of LPS treated offspring. doi:10.1016/j.schres.2010.02.435 Poster 208 REPEATED PHENCYCLIDINE (PCP) INCREASES IMPULSIVITY IN THE 5-CHOICE CONTINUOUS PERFORMANCE TEST IN RATS Sam A. Barnes, Jo C. Neill University of Bradford Bradford, West Yorksire, United Kingdom Background: Along with the positive and negative symptoms associated with schizophrenia, the disorder also results in a number of cognitive impairments which include attentional dysfunction and executive function impairments such as beha- vioural disinhibition, which manifests itself as an increase in impulsivity. We have consistently demonstrated that sub-chronic Phencyclidine (PCP) reliably produces cognitive impairments in rodents of relevance to schizophrenia and as outlined in MATRICS (matrics.ucla.edu). Attention and behavioural inhibition can be assessed in rodents using the 5 Choice Serial Reaction Time Task (5-CSRTT), where the animal is trained to report the detection of a brief presentation of light for a food reward. Impulsivity is measured by the number of premature responses made. The original 5-CSRTT is essentially a go-task, where the animal must respond to the stimulus in order to make a correct response. The 5 Choice Continuous Performance Test (5C -CPT) is an adaptation of the traditional 5-CSRTT, but also includes no-go trials in which a correct response is made when the animal withholds from responding, therefore assessing the ability of the animal to not only inhibit from incorrectly responding, but also to discriminate between the go and no-go trials (Young et al., 2009). Methods: 11 Female Hooded-Lister rats were trained in the 5C- CPT until a stable level of performance was achieved (>75% accuracy, <25% omissions and >65% correct rejections) for 3 consecutive days. The stimulus duration (SD) was 750mS, the variable ITI had a mean duration of 5s and following the presentation of the stimulus the animal had 2s to make a response (Limited Hold). The No-go trials consisted of all 5 apertures lighting up, the animal must correctly reject the stimulus by withholding its response for the duration of the LH. Correct responses in both go and no-go trials resulted in presentation of a food reward, incorrect responses resulted in a 5 s time out (TO), house light illuminates but no food pellet is delivered. The session lasts for either 30 minutes or 120 trials, whichever comes first. The animals were dosed using a repeated PCP regime adapted from Amitai et al., (2007) in which the animal received 5 consecutive doses of saline, followed by 5 consecutive doses of PCP (2.5 mg/kg, i.p.) and performance in the 5C-CPT was assessed 30 minutes following each dose. Results: Along with dysfunction in attention, repeated PCP resulted in robust impairments in behavioural inhibition. Com- pared to baseline performance, PCP treatment resulted in a significant increase in premature responding (p<0.05) where the animal made inappropriate responses during the ITI. This was coupled with a significant reduction in number of correct rejections made when presented with the no-go trial (p< 0.05). When signal detection analysis was employed it revealed that PCP treatment resulted in a significant increase in the false alarm rate (p < 0.05) and significant reduction in the sensitivity index (p < 0.05) which indicates that animals cannot distinguish between the go and no-go trials. Discussion: These data indicate that rats can be successfully trained to carry out the 5C-CPT and discriminate between the go and no-go trials to a predetermined level of performance. Secondly, repeated PCP treatment results in impairments in executive function which include behavioural disinhibition. This is analogous to performance by schizophrenia patients in the human CPT, showing translational properties of the deficits in 5C-CPT induced by PCP. doi:10.1016/j.schres.2010.02.436 Poster 209 NEONATAL TREATMENT WITH METHYLAZOXYMETHANOL ACETATE (MAM) AS A NEURODEVELOPMENTAL MODEL OF SCHIZOPHRENIA: BEHAVIORAL, PHARMACOLOGICAL AND MORPHOLOGICAL CHARACTERIZATION Ana M. Basso 1 , Peter Curzon 1 , Min Zhang 1 , Kelly B. Gallagher 1 , Katherine Salte 1 , Jordan Brown 1 , Arthur L. Nikkel 1 , R. Scott Bitner 1 , Mark Day 2 , Michael W. Decker 1 , Gerard B. Fox 2 , Lynne E. Rueter 1 , Chih-Liang Chin 2 1 Neuroscience Research, Global Pharmaceutical Research & Development, Abbott Laboratories Abbott Park, IL, USA; 2 Experimental Imaging, Advanced Technology, Global Pharmaceutical Research & Development, Abbott Laboratories Abbott Park, IL, USA Background: Genetic factors and early environmental insults during development are associated with higher risk of schizophrenia. Additionally, morphological changes in the brain of schizophrenia patients support the idea of a neurodevelopmental theory of the disease. Prenatal treatment to rats with methylazoximethanol acetate (MAM) has been proposed as a neurodevelopmental model of schizophrenia. MAM disrupts embryonic development, which subse- quently manifests during adulthood with behavioral deficits that mimic different symptom clusters of the disorder (positive, negative symptoms and cognitive deficits) and neuroanatomical changes relevant to schizophrenia. The goal of the study was to assess the behavioral, pharmacological and morphological changes in MAM- exposed rats as a disease-model for schizophrenia with potential value for the discovery of novel treatments and to further evaluate the Abstracts 272