Remage-Healey Luke, Bass Andrew H
Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA.
Horm Behav. 2006 Sep;50(3):432-41. doi: 10.1016/j.yhbeh.2006.05.007. Epub 2006 Jul 25.
Across vertebrates, androgens are rapidly elevated within minutes in response to aggressive or reproductive stimuli, yet it is unclear what the causal relationship is between fast androgen elevation and the ongoing (minute-by-minute) expression of behavior. This study tested the hypothesis that rapid increases in plasma steroid levels induce similarly rapid increases in both vocal behavior and the neurophysiological output of a central pattern generator that governs vocal behavior. In Gulf toadfish (Opsanus beta), males call to attract females to their nesting sites, and both males and females vocalize in aggressive interactions. Previous field experiments with males showed that simulated territorial challenges produce rapid and concurrent elevations in ongoing calling behavior and circulating levels of the teleost-specific androgen 11-ketotestosterone (11kT), but not the glucocorticoid cortisol. The current field experiments showed that non-invasive (food) delivery of 11kT, but not cortisol, induced an elevation within 10 min in the ongoing calling behavior of males. Electrophysiological experiments revealed that intramuscular injections of either 11kT or cortisol, but neither testosterone nor 17-beta-estradiol, induced increases within 5 min in the output of the vocal pattern generator in males, whereas only cortisol had similarly fast effects in females. The field behavioral results support predictions generated by the challenge hypothesis and also parallel the 11kT-dependent modulation of the vocal pattern generator in males. The cortisol effect on the vocal pattern generator in both sexes predicts that glucocorticoids regulate vocalizations in non-advertisement contexts. Together, these experiments provide strong support for the hypothesis that surges in circulating steroid levels play a causal role in shaping rapid changes in social behavior (vocalizations) through non-genomic-like actions on neural (vocal motor) circuits that directly encode behavioral patterning.
在整个脊椎动物中，雄激素会在几分钟内迅速升高以应对攻击或繁殖刺激，但目前尚不清楚雄激素快速升高与持续（每分钟）的行为表达之间的因果关系是什么。本研究检验了这样一个假设，即血浆类固醇水平的快速升高会导致发声行为以及控制发声行为的中枢模式发生器的神经生理输出同样快速增加。在海湾蟾鱼（Opsanus beta）中，雄性通过鸣叫吸引雌性到它们的巢穴，并且雄性和雌性在攻击性互动中都会发声。之前对雄性进行的野外实验表明，模拟领地挑战会使正在进行的鸣叫行为和硬骨鱼特有的雄激素11 - 酮睾酮（11kT）的循环水平迅速同时升高，但不会使糖皮质激素皮质醇升高。当前的野外实验表明，非侵入性（通过食物）给予11kT而非皮质醇，会在10分钟内使雄性正在进行的鸣叫行为增加。电生理实验表明，肌肉注射11kT或皮质醇，但不是睾酮或17 - β - 雌二醇，会在5分钟内使雄性发声模式发生器的输出增加，而只有皮质醇对雌性有同样快速的影响。野外行为结果支持了挑战假设所产生的预测，并且也与雄性中发声模式发生器的11kT依赖性调节相似。皮质醇对两性发声模式发生器的影响预示着糖皮质激素在非广告情境中调节发声。总之，这些实验为以下假设提供了有力支持：循环类固醇水平的激增通过对直接编码行为模式的神经（发声运动）回路进行类似非基因组的作用，在塑造社会行为（发声）的快速变化中起因果作用。
