The mediodorsal nucleus of the thalamus in rats .2. Behavioral and neurochemical effects of GABA agonists
The mediodorsal nucleus of the thalamus in rats .2. Behavioral and neurochemical effects of GABA agonists
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DOI：
10.1016/0306-4522(95)00352-j
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发表时间：
1996-01-01
期刊：
影响因子：
3.3
通讯作者：
Kalivas, PW
中科院分区：
文献类型：
--
作者：
Churchill, L;Zahm, DS;Kalivas, PW
本研究的目的是确定大鼠丘脑内侧背侧核中的GABA受体如何参与运动行为的调节。向背内侧核微量注射GABA(B)和GABA(A)激动剂巴氯芬和麝香酚产生剂量依赖性的运动增加，这种增加可被GABA(B)拮抗剂2-羟基糖芬联合应用所阻断。中线、外侧丘脑腹外侧部或侧脑室微量注射巴氯芬引起的运动增加明显较小，呈剂量依赖关系，提示巴氯芬诱导的运动的解剖部位位于背内侧核。微量注射巴氯芬引起的运动反应与前额叶皮质多巴胺代谢的降低和伏核核心的代谢增加有关，但与伏隔壳和背外侧纹状体无关。这些结果表明，GABA能传入内侧背侧核可能与运动活动的紧张性抑制音相反。数据还表明，巴氯芬在丘脑内侧背侧产生的运动反应可能是通过抑制调节中皮质边缘多巴胺传递的前额叶皮质的投射而产生的。
The aim of this study was to determine how GABA receptors in the mediodorsal nucleus of the thalamus in rats might contribute to the regulation of locomotor behavior. Microinjections of the GABA(B) and GABA(A) agonists, baclofen and muscimol, into the mediodorsal nucleus produced dose-dependent increases in locomotion that were blocked by co-administration of the GABA(B) antagonist, 2-hydroxysaclofen. Microinjection of baclofen along the midline, lateral into the ventrolateral thalamus or into the lateral ventricles produced significantly smaller dose-dependent increases in locomotion, indicating that the anatomical locus for baclofen-induced locomotion resides in the mediodorsal nucleus. The motor response elicited by microinjected baclofen was associated with a reduction in dopamine metabolism in the prefrontal cortex and an increase in metabolism in the core of the nucleus accumbens, but not in the accumbal shell or the dorsolateral striatum.These results suggest that GABAergic afferents to the mediodorsal nucleus may oppose a tonic inhibitory tone on locomotor activity. The data also suggest that the motor response produced by baclofen in the mediodorsal thalamus may arise by inhibiting the projections to the prefrontal cortex which modulate mesocorticolimbic dopamine transmission.