Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, United States.
Auton Neurosci. 2012 Jul 2;169(1):28-33. doi: 10.1016/j.autneu.2012.03.001. Epub 2012 Mar 29.
Hypothalamic oxytocin (OXT) has stress-attenuating effects. Social interaction in a positive environment continuously activates OXT release system. We have recently shown that pair housing restores delayed gastric emptying following chronic heterotypic stress, via up-regulation of OXT mRNA expression in rats. We tested the hypothesis that affiliative behavior attenuates stress responses via upregulating OXT expression. Adult male SD rats were divided into two groups: the rat with a stressed partner (RSP) and the rat with a non-stressed partner (RNSP). RSPs were pair housed with a partner that received different types of stress for 7 consecutive days (chronic heterotypic stress). RNSPs were pair housed with a partner who did not receive any stress. After each stress loading, the rats were returned to their home cages and the behaviors of RSPs and RNSPs toward their partners were videotaped. After the study completion, RSPs and RNSPs were loaded with acute restraint stress. Then, gastric emptying and colonic transit were measured. Corticotropin releasing factor (CRF) and OXT expression in the paraventricular nucleus (PVN) were evaluated by real time RT-PCR and immunohistochemistry. The time of affiliative behaviors toward their partners was increased in RSPs, compared to that of RNSPs. Delayed gastric emptying and accelerated colonic transit induced by acute restraint stress were significantly attenuated in RSPs, compared to RNSPs. CRF expression was reduced, while OXT expression was increased in RSPs in response to acute stress, compared to controls. It is suggested that affiliative behaviors may upregulate hypothalamic OXT expression, which in turn attenuates stress responses.
下丘脑催产素（OXT）具有减轻压力的作用。积极的社会互动会不断激活 OXT 释放系统。我们最近发现，在大鼠中，通过上调 OXT mRNA 表达，配对饲养可以恢复慢性异性应激后的胃排空延迟。我们假设，亲社会行为通过上调 OXT 表达来减轻应激反应。成年雄性 SD 大鼠分为两组：有应激伴侣的大鼠（RSP）和无应激伴侣的大鼠（RNSP）。RSP 与接受不同类型应激的伴侣连续 7 天配对饲养（慢性异性应激）。RNSP 与未接受任何应激的伴侣配对饲养。每次应激后，大鼠被放回其巢箱，记录 RSP 和 RNSP 对其伴侣的行为。研究完成后，RSP 和 RNSP 接受急性束缚应激。然后，测量胃排空和结肠转运。通过实时 RT-PCR 和免疫组织化学评估室旁核（PVN）中的促肾上腺皮质释放因子（CRF）和 OXT 表达。与 RNSP 相比，RSP 对其伴侣的亲社会行为时间增加。与 RNSP 相比，RSP 中由急性束缚应激引起的胃排空延迟和结肠转运加速明显减轻。RSP 对急性应激的反应中，CRF 表达减少，而 OXT 表达增加。这表明，亲社会行为可能上调下丘脑 OXT 表达，从而减轻应激反应。
