School of Psychology, University of Sydney, Sydney, Australia.
PLoS One. 2011;6(11):e27237. doi: 10.1371/journal.pone.0027237. Epub 2011 Nov 16.
Previous studies have suggested that administration of oxytocin (OT) can have modulatory effects on social and anxiety-like behavior in mammals that may endure beyond the time of acute OT administration. The current study examined whether repeated administration of OT to male Wistar rats (n = 48) during a key developmental epoch (early adolescence) altered their physiology and behavior in later-life. Group housed rats were given intraperitoneal injections of either 1 mg/kg OT or vehicle during early adolescence (post natal-days [PND] 33-42). OT treatment caused a transient inhibition of body weight gain that recovered quickly after the cessation of treatment. At PND 50, the rats pre-treated with OT displayed less anxiety-like behavior on the emergence test, while at PND 55 they showed greater levels of social interaction. A subgroup of OT pre-treated rats examined at PND 63 showed a strong trend towards increased plasma OT levels, and also displayed significantly increased OT receptor mRNA in the hypothalamus. Rats pre-treated with OT and their controls showed similar induction of beer intake in daily 70 min test sessions (PND 63 onwards) in which the alcohol concentration of beer was gradually increased across days from 0.44% to 4.44%. However, when given ad libitum access to beer in their home cages from PND 72 onwards (early adulthood), consumption of beer but not water was significantly less in the OT pre-treated rats. A "booster" shot of OT (1 mg/kg) given after 25 days of ad libitum access to beer had a strong acute inhibitory effect on beer intake without affecting water intake. Overall these results suggest that exogenous OT administered during adolescence can have subtle yet enduring effects on anxiety, sociability and the motivation to consume alcohol. Such effects may reflect the inherent neuroplasticity of brain OT systems and a feed-forward effect whereby exogenous OT upregulates endogenous OT systems.
先前的研究表明，催产素（OT）的给药可以对哺乳动物的社会和焦虑样行为产生调节作用，这种作用可能会持续到急性 OT 给药时间之外。本研究检查了在关键发育阶段（青春期早期）反复给雄性 Wistar 大鼠（n=48）OT 是否会改变它们在以后的生活中的生理和行为。群养大鼠在青春期早期（出生后第 33-42 天）接受 1mg/kg OT 或载体的腹腔注射。OT 处理导致体重增加短暂抑制，在治疗停止后很快恢复。在 PND50，OT 预处理的大鼠在出现测试中表现出较少的焦虑样行为，而在 PND55 时它们表现出更高的社交互动水平。在 PND63 检查的 OT 预处理大鼠亚组显示出增加的血浆 OT 水平的强烈趋势，并且在下丘脑中也显示出 OT 受体 mRNA 的显著增加。OT 预处理的大鼠及其对照大鼠在每天 70 分钟测试期间（从 PND63 开始）表现出相似的啤酒摄入量增加，其中啤酒的酒精浓度在几天内从 0.44%逐渐增加到 4.44%。然而，当从 PND72 开始（成年早期）在其巢箱中自由获得啤酒时，OT 预处理的大鼠消耗的啤酒但不是水明显减少。在自由获得啤酒 25 天后给予 OT（1mg/kg）的“增强剂”注射对啤酒摄入量具有强烈的急性抑制作用，而不影响水摄入量。总的来说，这些结果表明，青春期给予外源性 OT 可以对焦虑、社交能力和饮酒的动机产生微妙但持久的影响。这种作用可能反映了大脑 OT 系统的固有神经可塑性和前馈效应，即外源性 OT 上调内源性 OT 系统。
