Sex- and Genotype-Dependent Nicotine-Induced Behaviors in Adolescent Rats with a Human Polymorphism (rs2304297) in the 3′-UTR of the CHRNA6 Gene |
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Authors: | Anjelica Cardenas Yu Bai Yasamin Hajy Heydary Jiaqi Li Frances M. Leslie Shahrdad Lotfipour |
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Affiliation: | 1.Department of Pharmaceutical Sciences, College of Health Sciences, University of California, Irvine, CA 92697, USA; (Y.H.H.); (F.M.L.); (S.L.);2.Department of Biological Sciences, University of California, Irvine, CA 92697, USA; (Y.B.); (J.L.);3.Department of Emergency Medicine, School of Medicine, University of California, Irvine, CA 92697, USA;4.Pathology and Laboratory Medicine, School of Medicine, University of California, Irvine, CA 92697, USA |
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Abstract: | In human adolescents, a single nucleotide polymorphism (SNP), rs2304297, in the 3′-UTR of the nicotinic receptor subunit gene, CHRNA6, has been associated with increased smoking. To study the effects of the human CHRNA6 3′-UTR SNP, our lab generated knock-in rodent lines with either C or G SNP alleles. The objective of this study was to determine if the CHRNA6 3′-UTR SNP is functional in the knock-in rat lines. We hypothesized that the human CHRNA6 3′-UTR SNP knock-in does not impact baseline but enhances nicotine-induced behaviors. For baseline behaviors, rats underwent food self-administration at escalating schedules of reinforcement followed by a locomotor assay and a series of anxiety tests (postnatal day (PN) 25-39). In separate cohorts, adolescent rats underwent 1- or 4-day nicotine pretreatment (2×, 30 μg/kg/0.1 mL, i.v.). After the last nicotine injection (PN 31), animals were assessed behaviorally in an open-field chamber, and brain tissue was collected. We show the human CHRNA6 3′-UTR SNP knock-in does not affect food reinforcement, locomotor activity, or anxiety. Further, 4-day, but not 1-day, nicotine exposure enhances locomotion and anxiolytic behavior in a genotype- and sex-specific manner. These findings demonstrate that the human CHRNA6 3′-UTR SNP is functional in our in vivo model. |
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Keywords: | CHRNA6 locomotor activity anxiety-like behavior adolescent pharmacogenetics |
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