Department of Zoology, University of Wisconsin - Madison, 428 Birge Hall, 430 Lincoln Drive, Madison, WI 53706, USA.
Eur J Neurosci. 2014 Feb;39(4):650-62. doi: 10.1111/ejn.12429. Epub 2013 Nov 28.
Past studies in songbirds have highlighted a central role for the medial preoptic nucleus (mPOA) in context-appropriate vocal communication. During the breeding season, male songbirds sing primarily to attract females (sexually motivated song) and to repel competitors (agonistically motivated song). Past data have linked dopamine and D1 dopamine receptors in the mPOA to sexually motivated but not agonistically motivated song; however, direct effects of dopamine receptor manipulations in the mPOA on song have not been experimentally tested. Here, we tested the hypothesis that D1 receptor stimulation in the mPOA selectively influences sexually motivated male song, and the possibility that the effects of D1 receptor agonism differ at low and high doses. In a first study, breeding-condition male European starlings received infusions of saline or a single dose of the D1 receptor agonist SKF 38393 on separate test days into the mPOA or hypothalamic control areas. Stimulation of D1 receptors in the mPOA triggered sexually motivated but not agonistically motivated song. A second study showed inverted-U shaped dose-response effects of the agonist, such that low levels of sexually motivated song were observed at low and high levels of D1 receptor activation. A third study showed that the effects of the D1 receptor agonist were blocked by the D1 receptor antagonist SCH 23390. These findings suggest that an optimal level of D1 receptor stimulation in the mPOA is needed to facilitate sexually motivated vocal production. The results support a central, context-specific role for the mPOA in vocal communication, and more broadly demonstrate a complex, modulatory influence of D1 receptors in the mPOA on sexually motivated behavior.
过去在鸣禽中的研究强调了中脑前腹侧核（mPOA）在适当语境下的声音通讯中的核心作用。在繁殖季节，雄性鸣禽主要通过唱歌来吸引雌性（性动机的歌曲）和驱赶竞争者（竞争动机的歌曲）。过去的数据将 mPOA 中的多巴胺和 D1 多巴胺受体与性动机而非竞争动机的歌曲联系起来；然而，mPOA 中多巴胺受体操纵对歌曲的直接影响尚未经过实验测试。在这里，我们检验了这样一个假设，即 mPOA 中的 D1 受体刺激选择性地影响性动机的雄性歌曲，并且 D1 受体激动剂的作用在低剂量和高剂量下可能不同。在第一项研究中，繁殖条件下的雄性欧洲椋鸟在不同的测试日接受生理盐水或 D1 受体激动剂 SKF 38393 的单次剂量注入 mPOA 或下丘脑对照区。mPOA 中的 D1 受体刺激引发了性动机但不是竞争动机的歌曲。第二项研究表明，激动剂的剂量反应呈倒 U 形，即观察到低水平的性动机歌曲出现在 D1 受体激活的低水平和高水平。第三项研究表明，D1 受体激动剂的作用被 D1 受体拮抗剂 SCH 23390 阻断。这些发现表明，mPOA 中 D1 受体的最佳刺激水平有助于促进性动机的发声。结果支持了 mPOA 在声音通讯中的核心、特定情境作用，并更广泛地证明了 mPOA 中 D1 受体对性动机行为的复杂调节作用。
