Development of brain controlling mechanism of sexual orientation

成对的成年雄性蟋蟀会进行打斗，并立即决定它们的统治地位和从属地位。占统治地位的雄性通过摩擦前翅反复发出攻击性的（竞争性的）歌声。以前的研究表明，一个占主导地位的男性发出的侵略性的歌曲可以防止他自己大脑中的血清素（5-羟色胺; 5-HT）水平的降低。为了验证这一假设，我们删除了拨片（前翅的发声结构）从雄性蟋蟀和测量他们的大脑5-HT水平后，立即进行了10分钟的侵略性的相互作用，使用高效液相色谱法和免疫组化。一对拔去了拨片的雄性会争斗，并建立起清晰的主从关系，就像完整的雄性一样。除去羽毛的雄鸟经常摩擦它们的前翅，但不能发出歌声。大脑5-羟色胺水平的plectum-removed男性显着降低后立即积极的互动，无论他们的优势地位。5-HT的减少主要发生在大脑中央体。与此相反，在成对的完整的男性，积极的相互作用降低大脑5-HT水平的下属男性，但不是在占主导地位的男性。单独切除拨柄不影响脑5-HT水平。这些研究结果表明，由占主导地位的雄性蟋蟀发出的侵略性歌曲，而不是他的前翅旋转打开/关闭运动，防止他自己的大脑（特别是在中央身体）中的5-HT水平降低。这是强烈建议，在积极的雄性蟋蟀，自我产生的歌曲影响大脑功能，如合成和/或5-羟色胺在中枢神经元的降解，导致突触传递的改变。

Pairs of adult male crickets fight and immediately determine their dominant and subordinate statuses. The dominant male repeatedly produces aggressive (rival) song by rubbing his forewings together. Previous studies have suggested that aggressive song emitted by a dominant male prevents reduction of serotonin (5-hydroxytryptamine ; 5-HT) levels in his own brain. To test this hypothesis, we removed the plectrum (a sound-producing structure in the forewing) from male crickets and measured their brain 5-HT levels immediately after a 10-min aggressive interaction, using high-performance liquid chromatography and immunohistochemistry. Pairs of plectrum-removed males fought and established clear dominant-subordinate relationships, like the case of intact males. The plectrum-removed dominant males frequently rubbed their forewings together, but were unable to produce song. Brain 5-HT levels in the plectrum-removed males were significantly reduced immediately after the aggressive interaction, regardless of their dominance status. The decrease in 5-HT primarily occurred in the central body of the brain. In contrast, in pairs of intact males, aggressive interaction reduced brain 5-HT levels in the subordinate males, but not in the dominant males. Plectrum removal alone did not affect the brain 5-HT levels. These findings demonstrate that aggressive song emitted by a dominant male cricket, but not rotation opening/closing movements of his forewings, prevents reduction of 5-HT levels in his own brain (especially in the central body). It is strongly suggested that in aggressive male crickets, self-generated song affects brain functions such as synthesis and/or degradation of 5-HT in neurons of the central body, resulting in alteration of synaptic transmission.