Daberkow D P, Riedy M D, Kesner R P, Keefe K A
Depts of Pharmacology and Toxicology, Program in Neuroscience, University of Utah, Salt Lake City, UT 84112, USA.
Eur J Neurosci. 2007 Jul;26(1):228-41. doi: 10.1111/j.1460-9568.2007.05630.x.
The dorsal striatum is involved in motor-response learning, but the extent to which distinct populations of striatal efferent neurons are differentially involved in such learning is unknown. Activity-regulated, cytoskeleton-associated (Arc) protein is an effector immediate-early gene implicated in synaptic plasticity. We examined arc mRNA expression in striatopallidal vs. striatonigral efferent neurons in dorsomedial and dorsolateral striatum of rats engaged in reversal learning on a T-maze motor-response task. Male Sprague-Dawley rats learned to turn right or left for 3 days. Half of the rats then underwent reversal training. The remaining rats were yoked to rats undergoing reversal training, such that they ran the same number of trials but ran them as continued-acquisition trials. Brains were removed and processed using double-label fluorescent in situ hybridization for arc and preproenkephalin (PPE) mRNA. In the reversal, but not the continued-acquisition, group there was a significant relation between the overall arc mRNA signal in dorsomedial striatum and the number of trials run, with rats reaching criterion in fewer trials having higher levels of arc mRNA expression. A similar relation was seen between the numbers of PPE(+) and PPE(-) neurons in dorsomedial striatum with cytoplasmic arc mRNA expression. Interestingly, in behaviourally activated animals significantly more PPE(-) neurons had cytoplasmic arc mRNA expression. These data suggest that Arc in both striatonigral and striatopallidal efferent neurons is involved in striatal synaptic plasticity mediating motor-response learning in the T-maze and that there is differential processing of arc mRNA in distinct subpopulations of striatal efferent neurons.
背侧纹状体参与运动反应学习，但不同的纹状体传出神经元群体在这种学习中的参与程度尚不清楚。活动调节的细胞骨架相关蛋白（Arc）是一种与突触可塑性有关的效应即刻早期基因。我们研究了参与T迷宫运动反应任务逆向学习的大鼠背内侧和背外侧纹状体中，纹状体苍白球传出神经元与纹状体黑质传出神经元中Arc mRNA的表达情况。雄性Sprague-Dawley大鼠学习向左或向右转3天。然后，一半的大鼠接受逆向训练。其余的大鼠与接受逆向训练的大鼠配对，使它们进行相同次数的试验，但作为持续习得试验进行。取出大脑，使用双标记荧光原位杂交技术检测Arc和前脑啡肽原（PPE）mRNA。在逆向训练组而非持续习得组中，背内侧纹状体中总的Arc mRNA信号与试验次数之间存在显著相关性，达到标准所需试验次数较少的大鼠Arc mRNA表达水平较高。背内侧纹状体中PPE（+）和PPE（-）神经元数量与细胞质Arc mRNA表达之间也存在类似的关系。有趣的是，在行为激活的动物中，显著更多的PPE（-）神经元有细胞质Arc mRNA表达。这些数据表明，纹状体黑质和纹状体苍白球传出神经元中的Arc都参与了介导T迷宫运动反应学习的纹状体突触可塑性，并且在不同的纹状体传出神经元亚群中Arc mRNA存在差异处理。
