Department of Pharmaceutical Sciences, College of Health Sciences, University of California, Irvine, CA 92697, USA.
Department of Biological Sciences, University of California, Irvine, CA 92697, USA.
Int J Mol Sci. 2022 Mar 15;23(6):3145. doi: 10.3390/ijms23063145.
In human adolescents, a single nucleotide polymorphism (SNP), rs2304297, in the 3'-UTR of the nicotinic receptor subunit gene, 6, has been associated with increased smoking. To study the effects of the human 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 3'-UTR SNP is functional in the knock-in rat lines. We hypothesized that the human 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 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 3'-UTR SNP is functional in our in vivo model.
在人类青少年中，烟碱受体亚基基因 6 的 3'-UTR 中的单个核苷酸多态性 (SNP)，rs2304297，与吸烟增加有关。为了研究人类 3'-UTR SNP 的影响，我们的实验室生成了带有 C 或 G SNP 等位基因的敲入啮齿动物品系。本研究的目的是确定 3'-UTR SNP 在敲入大鼠品系中是否具有功能。我们假设人类 3'-UTR SNP 敲入不会影响基线，但增强尼古丁诱导的行为。对于基线行为，大鼠在强化递增时间表下进行食物自我给药，然后进行运动测定和一系列焦虑测试（出生后第 25-39 天）。在不同的队列中，青春期大鼠接受 1 或 4 天尼古丁预处理（2×，30μg/kg/0.1mL，iv.）。在最后一次尼古丁注射后（PN31），动物在开放场室中进行行为评估，并收集脑组织。我们表明，人类 3'-UTR SNP 敲入不会影响食物强化、运动活动或焦虑。此外，4 天而非 1 天的尼古丁暴露以基因型和性别特异性的方式增强运动和抗焦虑行为。这些发现表明，人类 3'-UTR SNP 在我们的体内模型中具有功能。
