Peri-pubertal exposure to testicular hormones organizes response to novel environments and social behaviour in adult male rats.
Peri-pubertal exposure to testicular hormones organizes response to novel environments and social behaviour in adult male rats.
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DOI：
10.1016/j.yhbeh.2015.07.003
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发表时间：
2015-07
影响因子：
3.5
通讯作者：
Duval C
中科院分区：
文献类型：
--
作者：
Brown GR;Kulbarsh KD;Spencer KA;Duval C
以前的研究表明，在青春期周围暴露于睾丸激素对成年啮齿动物的性行为和潜在的神经机制有长期的、有组织的影响。然而，青春期周围睾丸激素对行为和大脑功能的其他方面的组织影响还不是很清楚。在这里，我们调查了青春期周围睾丸激素暴露对对新环境的后期行为反应的影响，以及对参与对新奇事物反应的不同大脑区域的激素受体的影响。雄性啮齿动物通常比雌性啮齿动物在新环境的暴露区域花费更少的时间，这种性别差异在青春期周围出现。在青春期前或青春期后对雄性Lister-hodicus(褐家鼠)进行去势，然后在三种新环境(高架正迷宫、明暗箱、开阔场地)和成年后的物体/社会新奇任务中进行测试。定量检测雄激素受体(AR)、雌激素受体(ER1)和促肾上腺皮质激素释放因子受体(CRF-R2)在下丘脑、海马区和杏仁内侧核的表达。结果表明，青春期前被去势的雄性在高架迷宫和明暗盒子暴露区域花费的时间比青春期后被去势的雄性更多，这也证实了青春期周围的激素暴露影响了后来对异性同种动物的反应。在被检查的任何大脑区域中，青春期前和青春期后去势的男性的激素受体基因表达水平没有差异。因此，这项研究表明，青春期周围时期的睾丸激素暴露会使后来对新环境的反应男性化，尽管其神经机制仍未完全阐明。青春期前和青春期后去势的雄性大鼠在新的环境中进行测试，并使用新的异性同种异体。在青春期前被阉割的雄性花更多的时间在新奇环境的暴露区域。青春期后被阉割的雄性花更多的时间研究异性的共性。治疗组之间在脑内激素受体基因表达水平没有发现差异。在青春期周围暴露于睾丸激素会组织以后的行为。
Previous research has shown that exposure to testicular hormones during the peri-pubertal period of life has long-term, organizational effects on adult sexual behaviour and underlying neural mechanisms in laboratory rodents. However, the organizational effects of peri-pubertal testicular hormones on other aspects of behaviour and brain function are less well understood. Here, we investigated the effects of manipulating peri-pubertal testicular hormone exposure on later behavioural responses to novel environments and on hormone receptors in various brain regions that are involved in response to novelty. Male rodents generally spend less time in the exposed areas of novel environments than females, and this sex difference emerges during the peri-pubertal period. Male Lister-hooded rats (Rattus norvegicus) were castrated either before puberty or after puberty, then tested in three novel environments (elevated plus-maze, light–dark box, open field) and in an object/social novelty task in adulthood. Androgen receptor (AR), oestrogen receptor (ER1) and corticotropin-releasing factor receptor (CRF-R2) mRNA expression were quantified in the hypothalamus, hippocampus and medial amygdala. The results showed that pre-pubertally castrated males spent more time in the exposed areas of the elevated-plus maze and light–dark box than post-pubertally castrated males, and also confirmed that peri-pubertal hormone exposure influences later response to an opposite-sex conspecific. Hormone receptor gene expression levels did not differ between pre-pubertally and post-pubertally castrated males in any of the brain regions examined. This study therefore demonstrates that testicular hormone exposure during the peri-pubertal period masculinizes later response to novel environments, although the neural mechanisms remain to be fully elucidated. Pre- and post-pubertally castrated male rats were tested in novel environments and with novel opposite-sex conspecifics. Males that were castrated before puberty spent more time in the exposed areas of novel environments. Males that were castrated after puberty spent more time investigating opposite-sex conspecifics. No differences were found in hormone receptor gene expression levels in the brain between treatment groups. Exposure to testicular hormones during the peri-pubertal period organizes later behaviour.