Bentley G E, Van't Hof T J, Ball G F
Department of Psychology, Behavioral Neuroendocrinology Group, The Johns Hopkins University, Baltimore, MD 21218, USA.
Proc Natl Acad Sci U S A. 1999 Apr 13;96(8):4674-9. doi: 10.1073/pnas.96.8.4674.
Neuroplasticity in the vocal control system of songbirds is strongly influenced by seasonal fluctuations in circulating testosterone. These seasonally plastic telencephalic structures are implicated in the learning and production of song in songbirds. The role of the indoleamine melatonin in seasonal adaptations in birds has remained unclear. In this experiment, European starlings were castrated to remove the neuromodulating activity of gonadal steroids and were exposed to different photoperiods to induce reproductive states characteristic of different seasonal conditions. Long days increased the volume of the song-control nucleus high vocal center compared with its volume on short days. Exogenous melatonin attenuated the long-day-induced volumetric increase in high vocal center and also decreased the volume of another song-control nucleus, area X. This effect was observed regardless of reproductive state. To our knowledge, this is the first direct evidence of a role for melatonin in functional plasticity within the central nervous system of vertebrates.
鸣禽发声控制系统中的神经可塑性受到循环睾酮季节性波动的强烈影响。这些具有季节性可塑性的端脑结构与鸣禽歌曲的学习和产生有关。吲哚胺褪黑素在鸟类季节性适应中的作用尚不清楚。在本实验中，对欧洲椋鸟进行阉割以去除性腺类固醇的神经调节活性，并使其暴露于不同的光照周期以诱导不同季节条件下的生殖状态。与短日照相比，长日照增加了发声控制核团高级发声中枢的体积。外源性褪黑素减弱了长日照诱导的高级发声中枢体积增加，同时也减小了另一个发声控制核团X区的体积。无论生殖状态如何，均观察到这种效应。据我们所知，这是褪黑素在脊椎动物中枢神经系统功能可塑性中发挥作用的首个直接证据。
