Division of Systems Neuroscience, National Brain Research Centre (Deemed University), NH-8, Manesar, Gurugram, Haryana, 122052, India.
Brain Struct Funct. 2019 Nov;224(8):2939-2972. doi: 10.1007/s00429-019-01947-0. Epub 2019 Aug 31.
Although the catecholaminergic circuitry in the zebra finch brain has been well studied, there is little information regarding the postsynaptic targets of dopamine. To answer this question, we looked at overall patterns of immunoreactivity for DARPP-32 (a dopamine and cAMP-regulated phosphoprotein, present mostly in dopaminoceptive neurons) in adult male zebra finches. Our results demonstrated that as in mammals and other avian species, DARPP-32 expression was highest in both medial and lateral striatum. Interestingly, a specific pattern of immunoreactivity was observed in the song control system, with 'core' song control regions, that is, LMANcore (lateral magnocellular nucleus of the anterior nidopallium), RA (nucleus robustus arcopallialis) and HVC being less immunoreactive for DARPP-32 than 'shell' areas such as LMANshell, RAcup, AId (intermediate arcopallium) and HVCshelf. Our results suggest that whereas dopamine may modulate the shell pathways at various levels of the AFP, dopaminergic modulation of the core pathway occurs mainly through Area X, a basal ganglia nucleus. Further, secondary sensory cortices including the perientopallial belt, Fields L1 and L3 had higher DARPP-32-immunoreactivity than primary sensory cortical areas such as the pallial basolateral nucleus, entopallium proper and Field L2, corresponding to somatosensory, visual and auditory systems, respectively. We also found DARPP-32-rich axon terminals surrounding dopaminergic neurons in the ventral tegmental area-substantia nigra complex which in turn project to the striatum, suggesting that there may be a reciprocal modulation between these regions. Overall, DARPP-32 expression appears to be higher in areas involved in integrating sensory information, which further supports the role of this protein as a molecular integrator of different signal processing pathways.
虽然斑马雀脑内的儿茶酚胺能通路已经得到了很好的研究，但关于多巴胺的突触后靶标知之甚少。为了解决这个问题，我们观察了成年雄性斑马雀中 DARPP-32（一种多巴胺和 cAMP 调节的磷酸蛋白，主要存在于多巴胺能神经元中）的总体免疫反应模式。我们的结果表明，与哺乳动物和其他鸟类物种一样，DARPP-32 的表达在中侧纹状体中最高。有趣的是，在歌唱控制系统中观察到了一种特定的免疫反应模式，即“核心”歌唱控制区域，即 LMANcore（前脑外侧核的外侧大细胞核）、RA（核粗壮弧形核）和 HVC 的 DARPP-32 免疫反应性低于“壳”区，如 LMANshell、RAcup、AId（中间弧形核）和 HVCshelf。我们的结果表明，虽然多巴胺可能在 AFP 的各个水平上调节壳途径，但多巴胺对核心途径的调节主要通过基底神经节核 Area X 发生。此外，包括旁顶带、Field L1 和 L3 在内的次级感觉皮层的 DARPP-32 免疫反应性高于初级感觉皮质区域，如大脑基底外侧核、内顶叶和 Field L2，分别对应于躯体感觉、视觉和听觉系统。我们还发现富含 DARPP-32 的轴突末梢环绕腹侧被盖区-黑质复合体中的多巴胺能神经元，而后者投射到纹状体，这表明这些区域之间可能存在相互调节。总的来说，DARPP-32 的表达似乎在整合感觉信息的区域中更高，这进一步支持了这种蛋白质作为不同信号处理途径的分子整合器的作用。
