Heck Detlef H, Roy Snigdha, Xie Ni, Waters Robert S
Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, College of Medicine, 855 Monroe Avenue, Memphis, Tennessee 38163, USA.
Physiol Behav. 2008 Jul 5;94(4):540-4. doi: 10.1016/j.physbeh.2008.03.011. Epub 2008 Mar 31.
Prenatal alcohol exposure (PAE) has been previously reported to result in behavioral and cognitive deficits that continue into adulthood. These deficits are often manifested by poor performance on higher-order cognitive motor tasks, difficulties in maintaining postural balance, slower reaction times, and deficits in fine motor performance. The central causes of these cognitive and motor deficits have been studied in human and animal models. Rats have been shown to be capable of performing skilled reaching and grasping movements with their forepaws that exhibit many components of skilled reaching also found in human and non-human primates. Whether PAE affects skilled reaching movements in rats is unknown. In the present study, we investigated the effect of PAE on skilled reaching and grasping behavior in rats. Pregnant Sprague-Dawley rats were intragastrically gavaged daily with alcohol at a dose of 6 g/kg body weight from gestation day one (G1) through G20 that yielded average blood alcohol levels between 265 and 343 mg/dL. Non-alcohol groups, pairfed (n=4) and chowfed (n=9), served as nutritionally-matched and normal controls, respectively to the alcohol treatment group (n=12). At 7 weeks of age, all rats were deprived of food for one day. The next day, rats were individually placed in test cages where food could only be accessed by reaching through a grid and grasping small food pellets (20 mg) on a tray. All rats were naive to the task. The major findings in this study are: a) PAE significantly increased the average number of minutes to make a successful skilled reach (Alc mean+/-SEM=97.3+/-16.9 min vs. non-Alc 52.3+/-9.6 min), b) once a successful skilled reach was learned, non-alcohol control rats were no better than Alc rats in using the skilled reach to acquire food, c) no significant differences between groups were observed in the amount of food consumption or changes in body weight during test sessions. These findings provide an important first step into the role that PAE plays for the learning of new skills and will lead to studies of central mechanisms underlying more complex skilled reaching behaviors.
先前有报道称，产前酒精暴露（PAE）会导致行为和认知缺陷，并持续至成年期。这些缺陷通常表现为在高阶认知运动任务中表现不佳、维持姿势平衡困难、反应时间延长以及精细运动表现缺陷。已在人类和动物模型中研究了这些认知和运动缺陷的核心原因。研究表明，大鼠能够用前爪进行熟练的抓握动作，这些动作展现出了人类和非人类灵长类动物中也存在的许多熟练抓握的组成部分。PAE是否会影响大鼠的熟练抓握动作尚不清楚。在本研究中，我们调查了PAE对大鼠熟练抓握行为的影响。从妊娠第1天（G1）至第20天，对怀孕的斯普拉格-道利大鼠每天经胃灌胃给予剂量为6 g/kg体重的酒精，这使得平均血液酒精水平在265至343 mg/dL之间。非酒精组，即配对喂养组（n = 4）和正常喂食组（n = 9），分别作为酒精处理组（n = 12）的营养匹配对照组和正常对照组。在7周龄时，所有大鼠禁食一天。第二天，将大鼠单独放入测试笼中，在笼中只有通过穿过网格并抓取托盘上的小食物颗粒（20毫克）才能获取食物。所有大鼠对该任务均不熟悉。本研究的主要发现如下：a）PAE显著增加了成功进行熟练抓握所需的平均分钟数（酒精组平均值±标准误 = 97.3±16.9分钟，而非酒精组为52.3±9.6分钟）；b）一旦学会了成功的熟练抓握动作，非酒精对照组大鼠在利用熟练抓握动作获取食物方面并不比酒精组大鼠更好；c）在测试期间，各组之间在食物消耗量或体重变化方面未观察到显著差异。这些发现为PAE在新技能学习中所起的作用提供了重要的第一步，并将引发对更复杂熟练抓握行为背后的中枢机制的研究。
