Ontogenetic differences in ethanol's motivational properties during infancy
Ontogenetic differences in ethanol's motivational properties during infancy
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DOI：
10.1016/j.alcohol.2011.09.026
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发表时间：
2012-05-01
期刊：
影响因子：
2.3
通讯作者：
Spear, Norman E.
中科院分区：
文献类型：
--
作者：
Nizhnikov, Michael E.;Marcos Pautassi, Ricardo;Spear, Norman E.
将条件刺激（CS）与乙醇配对通常会引起成年啮齿动物对条件刺激的厌恶。然而，暴露于乙醇的幼年大鼠（PD1-PD3）表现出对乙醇的食欲增强（Nizhnikov、Varlinskaya、Petrov 和 Spear，2006；Petrov、Varlinskaya 和 Spear，2003）。在婴儿期，这种对乙醇食欲特性的敏感性可能是暂时的，因为在出生后第二周，幼鼠往往会对与乙醇搭配的味道表现出条件性厌恶。本研究通过个体发育研究了乙醇的动机特性的变化以及这些变化背后的神经生物学。幼鼠接受 PD4 或 PD12 的味觉调节程序。给幼鼠口服 2.5% 体重的糖精溶液 (0.1%)，并在腹膜内 (i.p.) 注射六剂乙醇之一 (0.0-2.0 g/kg)。一天后，给幼崽注射糖精，并将体重增加百分比用作乙醇增强作用的指标。与对照幼崽和年长的 PD12 幼崽相比，PD4 幼崽对乙醇表现出更强的食欲，这通过摄入更多的糖精来表明。随后的实验表明，与 PD12 幼崽相比，PD4 幼崽对药物的厌恶特性不太敏感。在一次试验后，年长的幼鼠发现高剂量的乙醇厌恶，而 PD4 幼鼠则没有对这种剂量的乙醇产生厌恶。在低剂量的乙醇和最高剂量的κ阿片类激动剂之间观察到类似的结果模式。 PD12 动物对 kappa 阿片类激动剂没有适应，而年轻的大鼠则表现出食欲反应。这些结果说明了乙醇的动机特性的个体发生变化，在婴儿早期，随着年龄的增长，对其食欲特性的敏感性下降，而对其厌恶特性的反应性增加。 (C) 2012 Elsevier Inc. 保留所有权利。
Pairing a conditioned stimulus (CS) with ethanol generally produces aversion for that CS in adult rodents. However, infant rats (PD1-PD3) exposed to ethanol demonstrate appetitive reinforcement to ethanol (Nizhnikov, Varlinskaya, Petrov, & Spear, 2006; Petrov, Varlinskaya, & Spear, 2003). This sensitivity to the appetitive properties of ethanol during infancy may be transient, as during the second postnatal week rat pups tend to exhibit conditioned aversions to flavors paired with ethanol. The present study examined changes in the motivation properties of ethanol through ontogeny and the neurobiology underlying these changes. Rat pups were exposed to a taste conditioning procedure on PD4 or PD12. Rat pups were intraorally infused with 2.5% of their body weight of saccharin solution (0.1%) and immediately after injected intraperitoneolly (i.p.) with one of six doses of ethanol (0.0-2.0 g/kg). A day later pups were given saccharine infusions and percent body weight gain was used as an index of ethanol's reinforcing effects. PD4 pups expressed appetitive reinforcement to ethanol, as indicated by greater saccharin intake, as compared to control counterparts and to the older PD12 pups. Subsequent experiments revealed that PD4 pups were less sensitive to the aversive properties of the drug than PD12 pups. The older pups found high doses of ethanol aversive while PD4 rat pups did not condition aversions to this dose of ethanol after a single trial. A similar pattern of results was observed between the low doses of ethanol and the highest doses of a kappa opioid agonist. The PD12 animals did not condition to the kappa opioid agonist, while the younger rats expressed an appetitive response. These results illustrate an ontogenetic change in the motivational properties of ethanol, with sensitivity to its appetitive properties declining and responsiveness to the aversive properties increasing with age during early infancy. (C) 2012 Elsevier Inc. All rights reserved.