Kumar Sandeep, Mohapatra Alok Nath, Pundir Arvind Singh, Kumari Mukta, Din Uzma, Sharma Sudha, Datta Atanu, Arora Vasav, Iyengar Soumya
National Brain Research Centre, Manesar, India.
Front Neurosci. 2020 Sep 17;14:554094. doi: 10.3389/fnins.2020.554094. eCollection 2020.
The organization of the anterior forebrain pathway (AFP) of songbirds important for context-dependent singing is similar to that of cortical basal ganglia loops (CBG) in mammals, which underlie motor behaviors including vocalization. Since different components of the AFP express high levels of μ-opioid receptors (μ-ORs) as do CBG loops, songbirds act as model systems to study the role of opioid modulation on vocalization and the motivation to sing. The AFP in songbirds includes the cortical/pallial region LMAN (lateral magnocellular nucleus of the anterior nidopallium) which projects to Area X, a nucleus of the avian basal ganglia. In the present study, microdialysis was used to infuse different doses of the opioid antagonist naloxone in LMAN of adult male zebra finches. Whereas all doses of naloxone led to significant decreases in the number of FD (female-directed) songs, only 100 and 200 ng/ml of naloxone affected their acoustic properties. The decrease in FD song was not accompanied by changes in levels of attention toward females or those of neurotransmitters (dopamine, glutamate, and GABA) in LMAN. An earlier study had shown that similar manipulations in Area X did not lead to alterations in the number of FD songs but had significantly greater effects on their acoustic properties. Taken together, our results suggest that there are reciprocal effects of OR modulation on cortical and basal ganglia components of the AFP in songbirds.
对于依赖情境的鸣叫而言，鸣禽前脑前部通路（AFP）的组织与哺乳动物的皮质基底神经节环路（CBG）相似，而CBG是包括发声在内的运动行为的基础。由于AFP的不同组成部分与CBG环路一样都表达高水平的μ-阿片受体（μ-ORs），鸣禽可作为研究阿片类物质调节对发声及鸣叫动机作用的模型系统。鸣禽的AFP包括皮质/ pallial区域LMAN（前巢皮质外侧大细胞核），它投射到鸟类基底神经节的一个核团X区。在本研究中，采用微透析法向成年雄性斑胸草雀的LMAN中注入不同剂量的阿片拮抗剂纳洛酮。虽然所有剂量的纳洛酮都导致向雌鸟定向（FD）鸣叫的数量显著减少，但只有100和200 ng/ml的纳洛酮影响其声学特性。FD鸣叫数量的减少并未伴随着对雌鸟注意力水平或LMAN中神经递质（多巴胺、谷氨酸和GABA）水平的变化。一项早期研究表明，对X区进行类似操作不会导致FD鸣叫数量的改变，但对其声学特性有显著更大的影响。综上所述，我们的结果表明，阿片受体调节对鸣禽AFP的皮质和基底神经节成分存在相互作用。
