Merullo Devin P, Angyal Caroline S, Stevenson Sharon A, Riters Lauren V
Department of Zoology, University of Wisconsin-Madison, Madison, Wis., USA.
Brain Behav Evol. 2016;88(2):81-92. doi: 10.1159/000448191. Epub 2016 Sep 10.
Some animals, including songbirds, vocalize at high rates when alone or in large groups. In songbirds, vocal behavior in these contexts is important for song learning and group cohesion. It is not obviously targeted at any particular individual and is described as 'undirected'. Studies suggest a role for dopamine (DA) in undirected song. The neuropeptide neurotensin (NT) can enhance dopaminergic signaling upon binding to the NT receptor 1 (NTR1) and is found in regions where DA can influence song, including the ventral tegmental area (VTA), septum, and the song control nucleus Area X. To begin to test the hypothesis that NT and DA in these regions interact to influence undirected song, we used quantitative real-time PCR to relate undirected singing to mRNA expression of NT, NTR1, tyrosine hydroxylase (TH; a synthetic enzyme for DA) and D1 and D2 receptors in male European starlings. TH and NT expression in VTA, and NT and D1 expression in Area X, positively correlated with song. NT markers also correlated positively with DA markers in VTA. Given the role of VTA projections to Area X in song learning, these results suggest that interactions between NT and DA in these regions may contribute to vocal learning. In septum, NTR1 expression positively correlated with song and NT and DA markers were correlated, suggesting that NT in this region may influence dopaminergic transmission to facilitate undirected vocalizations. Overall, these findings implicate interactions between NT and DA in affiliative communication.
一些动物，包括鸣禽，在独处或处于大群体中时会高频发声。在鸣禽中，这些情况下的发声行为对于歌曲学习和群体凝聚力很重要。它并非明显针对任何特定个体，被描述为“无定向的”。研究表明多巴胺（DA）在无定向鸣叫中起作用。神经肽神经降压素（NT）与神经降压素受体1（NTR1）结合后可增强多巴胺能信号传导，且在DA可影响鸣叫的区域被发现，包括腹侧被盖区（VTA）、隔区以及鸣叫控制核X区。为了开始检验这些区域中的NT和DA相互作用以影响无定向鸣叫这一假设，我们使用定量实时PCR来关联雄性欧洲椋鸟的无定向鸣叫与NT、NTR1、酪氨酸羟化酶（TH；一种DA合成酶）以及D1和D2受体的mRNA表达。VTA中的TH和NT表达，以及X区中的NT和D1表达，与鸣叫呈正相关。VTA中的NT标记物也与DA标记物呈正相关。鉴于VTA向X区的投射在歌曲学习中的作用，这些结果表明这些区域中NT和DA之间的相互作用可能有助于发声学习。在隔区，NTR1表达与鸣叫呈正相关，且NT和DA标记物相关，表明该区域中的NT可能影响多巴胺能传递以促进无定向发声。总体而言，这些发现表明NT和DA之间的相互作用在亲和性交流中起作用。
