Instrumental learning, but not performance, requires dopamine d1-receptor activation in the amygdala
Instrumental learning, but not performance, requires dopamine d1-receptor activation in the amygdala
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DOI：
10.1016/j.neuroscience.2005.06.038
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发表时间：
2005-01-01
期刊：
影响因子：
3.3
通讯作者：
Kelley, AE
中科院分区：
文献类型：
--
作者：
Andrzejewski, ME;Spencer, RC;Kelley, AE
大量的实验证据表明，多巴胺在强化物相关的过程中起着关键作用，比如学习和药物成瘾。多巴胺受体，特别是D1受体，被广泛认为是突触可塑性的调节剂。杏仁核包含多巴胺终端和多巴胺D1受体，与动机和学习密切相关。然而，关于D1受体在哺乳动物杏仁核的两个亚核，中央核和基底外侧复合体中的激活在工具性学习中的作用知之甚少。术后恢复和初步训练后，将双侧留置套管对准中央核或基底外侧复核的大鼠进行了12次杠杆按压蔗糖颗粒的训练。在前5次训练前，注射选择性D1拮抗剂R(+)-7-氯-8-羟基-3-甲基-l-苯基-2,3,4,5tetrahydro- 1h -3-benzazepine hydrochloride （0.3 nmol和3.0 nmol）对工具学习有影响。然后，所有的大鼠都被暴露在无药物的五个疗程中；各组按压杠杆的比例很快达到相同水平。在第11次训练前注射药物对表现没有影响。对照实验表明，大鼠的基本动机过程和一般运动反应（如自发进食和运动活动）完好无损。这些结果表明，中央核和基底外侧复合体d1受体的激活在大鼠获得杠杆按压蔗糖颗粒的过程中起重要作用，而不是在条件反射后的行为表现中起重要作用。我们提出，工具学习依赖于中央核和基底外侧复杂杏仁核的可塑性，并且D1受体的激活参与了这种可塑性背后的转录过程。(c) 2005年由Elsevier Ltd代表IBRO出版。
Substantial experimental evidence exists suggesting a critical role for dopamine in reinforcer-related processes, such as learning and drug addiction. Dopamine receptors, and in particular D1 receptors, are widely considered as modulators of synaptic plasticity. The amygdala contains both dopamine terminals and dopamine D1 receptors and is intimately involved in motivation and learning. However, little is known about the involvement of D1 receptor activation in two subnuclei of the mammalian amygdala, the central nucleus and basolateral complex in instrumental learning. Following recovery from surgery and preliminary training, rats with bilateral indwelling cannulae aimed at the central nucleus or basolateral complex were trained to lever-press for sucrose pellets over 12 sessions. Infusion of the selective D1 antagonist R(+)-7-chloro-8-hydroxy-3-methyl-l-phenyl-2,3,4,5tetrahydro-1H-3-benzazepine hydrochloride (0.3 nmol and 3.0 nmol) prior to the first five training sessions dose-dependently impaired instrumental learning when compared with vehicle-infused controls. All rats were then exposed to five sessions drug-free; lever-pressing quickly reached equal levels across groups. A drug infusion prior to an 11th session revealed no effect on performance. Control experiments indicated that basic motivational processes and general motor responses were intact, such as spontaneous feeding and locomotor activity. These results show an essential role for D1-receptor activation in both the central nucleus and basolateral complex on the acquisition of lever pressing for sucrose pellets in rats, but not the performance of the behavior once conditioned. We propose that instrumental learning is dependent on plasticity in the central nucleus and basolateral complex amygdala, and that D1 receptor activation participates in transcriptional processes that underlie this plasticity. (c) 2005 Published by Elsevier Ltd on behalf of IBRO.