Systems Neuroscience, Department of Neuroscience, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan.
Systems Neuroscience, Department of Neuroscience, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan.
Behav Brain Res. 2014 May 1;264:197-206. doi: 10.1016/j.bbr.2014.02.007. Epub 2014 Feb 15.
In rodents, the disruption of social-rearing conditions before normal weaning induces emotional behavioral abnormalities, such as anxiety, motor activity dysregulation, and stress vulnerability. The beneficial effects of exercise after normal weaning on emotional regulation have been well documented. However, effects of exercise before normal weaning on emotion have not been reported. We examined whether voluntary wheel running (R) during social isolation after early weaning (early weaning/isolation; EI) from postnatal day (PD) 14-30 could prevent EI-induced emotional behavioral abnormalities in Sprague-Dawley rats. Compared with control rats reared with their dam and siblings until PD30, rats performed R during EI (EI+R) and EI rats demonstrated greater locomotion and lower grooming activity in the open-field test (OFT) during the juvenile period. Juvenile EI ± R rats showed greater learned helplessness (LH) after exposure to inescapable stress (IS; electric foot shock) than IS-exposed control and EI rats. In contrast, EI rats showed increased locomotion in the OFT and LH after exposure to IS compared with control rats during adulthood; this was not observed in EI ± R rats. Both EI and EI ± R rats exhibited greater rearing activity in the OFT than controls during adulthood. EI did not increase anxiety in the OFT and elevated plus-maze. These results suggested that R during EI until normal weaning prevented some of the EI-induced behavioral abnormalities, including hyperlocomotor activity and greater LH, during adulthood but not in the juvenile period.
在啮齿类动物中，正常断奶前社会养育条件的破坏会导致情绪行为异常，如焦虑、运动活动失调和应激易感性。正常断奶后运动对情绪调节的有益影响已有充分记录。然而，正常断奶前运动对情绪的影响尚未报道。我们研究了在早期断奶（从出生后第 14 天到第 30 天）后进行社交隔离期间进行自愿轮跑（R）是否可以预防早期断奶引起的 Sprague-Dawley 大鼠情绪行为异常。与直到 PD30 与母鼠和兄弟姐妹一起饲养的对照大鼠相比，在 EI 期间进行 R 的大鼠（EI+R）和 EI 大鼠在幼年时期的开放式场测试（OFT）中表现出更高的运动和更低的梳理活动。幼年 EI ± R 大鼠在暴露于不可逃避的应激（IS；电脚刺激）后表现出更大的习得性无助（LH），而暴露于 IS 的对照和 EI 大鼠则没有。相比之下，在成年期，EI 大鼠在暴露于 IS 后比对照大鼠表现出更高的 OFT 运动和 LH；而在 EI ± R 大鼠中则没有观察到这种情况。在成年期，EI 和 EI ± R 大鼠在 OFT 中的饲养活动均高于对照组。EI 不会增加 OFT 和高架十字迷宫中的焦虑。这些结果表明，在正常断奶前进行 EI 期间的 R 可以预防部分 EI 引起的行为异常，包括成年期的过度运动活动和更大的 LH，但在幼年期则不会。
