1. Concurrent Choice between Cues for Social Interaction and Amphetamine in Adolescent and Adult Rats: Effects of Housing Condition Justin R. Yates a,b, Joshua S. Beckmann a,b, Andrew C. Meyer c, & Michael T. Bardo a,b a Department of Psychology, University of Kentucky b Center for Drug Abuse Research Translation (CDART) c Department of Psychiatry, University of Vermont Introduction Human adolescents are more likely to experiment with drugs of abuse in the presence or their peers [1] Dyadic social interactions have also been described as an essential therapeutic factor in abstaining from drugs of abuse [2] Previous preclinical research has shown that social interaction reverses psychostimulant reward in individually-housed adult rats [3]. The present study was designed to determine if social interaction can attenuate amphetamine (AMPH) reward in individually- or pair-housed adolescent and adult rats Methods Animals: Male Sprague Dawley rats arrived at postnatal day (PND) 21 (n=54) or PND 60 (n=44) and were housed individually or in pairs. Procedure: Beginning on PND 28 (adolescent) or PND 67 (adult), rats went through a 10-day conditioned place preference (CPP) paradigm. Session 1 (Pre-test): Rats allowed to explore all three compartments of the CPP chamber for 15 min Sessions 2-9 (Conditioning): Rats were treated on alternating days as follows: (1) AMPH (1 mg/kg, s.c.) in one compartment (counterbalanced) + saline in the other; (2) saline with a social partner in one compartment + saline alone in the other; or (3) saline with a social partner in one compartment + AMPH alone in the other. Each conditioning session lasted 30 min. Session 10 (Posttest): Rats allowed to explore all three compartments for 15 min Analyses: Preference score calculated following posttest: Figure 1. References Acknowledgements Funding provided by NIH grants P50 DA05312, R01 DA 12964 and T32 DA016176. Figure 2. Discussion Overall results suggest that individually-housed adolescent rats were most sensitive to the rewarding effect of social interaction, and this hypersensitivity to social reward effectively competed with AMPH reward Future studies will examine other parametric manipulations, including: 1) AMPH dose 2) Duration of conditioning trial 3) Sex differences Figure 3. Experiments 1 & 2 Time spent (in sec) in social interaction/AMPH chamber Time spent (in sec) in social interaction/AMPH chamber AND saline chamber X100 Experiment 3 Time spent (in sec) in social interaction chamber Time spent (in sec) in social interaction chamber AND AMPH chamber X100 [1] Bahr SJ, Hoffmann JP, Yang X (2005) Parental and peer influences on the risk of adolescent drug use. The Journal of Primary Prevention, 26, 529-551. [2] Grawe K (1997) Research-informed psychotherapy. Psychotherapy Research, 7, 1-19 [3] Fritz M, El Rawas R, Salti A, Klement S, Bardo MT, Kemmler G, Dechant G, et al. (2011) Reversal of cocaine- conditioned place preference and mesocorticolimbic Zif268 expression by social interaction in rats. Addiction Biology, 16, 273-284. Adolescent AMPH Adolescent Saline Adult AMPH Adult Saline Conditioning Trial 1 26.8 (± 2.3)#20.7 (± 1.4)20.6 (± 1.0)20.7 (± 2.2) Conditioning Trial 2 27.7 (± 2.1)*20.2 (± 1.7)24.1 (± 1.0)*19.1 (± 2.0) Conditioning Trial 3 28.2 (± 2.2)*19.8 (± 1.6)28.4 (± 1.4)*18.3 (± 1.3) Conditioning Trial 4 30.5 (± 2.9)*18.1 (± 1.6)29.8 (± 1.4)*19.76 (± 1.6) Table 1. Locomotor activity (mean photobeam breaks ± SEM) during conditioning trials for Experiment 2 (AMPH-induced CPP) *p <.05, relative to saline #p <.05, relative to adults treated with AMPH Note: Data from individually- and pair-housed animals have been combined into one group *p <.05, relative to a preference score of 50 #p <.05, individually-housed adolescents relative to pair-housed adolescents