Abstract：
In mammals, some physiological conditions are associated with the high brain oxytocin (OXT) system activity. These include lactation in females and mating in males and females, both of which have been linked to reduced stress responsiveness and anxiolysis. Also, in a murine model of social fear conditioning (SFC), enhanced brain OXT signaling in lactating mice, specifically in the lateral septum (LS), was reported to underlie reduced social fear expression. Here, we studied the effects of mating in male mice on anxiety-related behaviour, social (and cued) fear expression and its extinction, and the activity of OXT neurons reflected by cFos expression and OXT release in the LS and amygdala. We further focused on the involvement of brain OXT in the mating-induced facilitation of social fear extinction. We could confirm the anxiolytic effect of mating in male mice irrespective of the occurrence of ejaculation. Further, we found that only successful mating resulting in ejaculation (Ej+) facilitated social fear extinction, whereas mating without ejaculation (Ej-) did not. In contrast, mating did not affect cues fear expression. Using the cellular activity markers cFos and pErk, we further identified the ventral LS (vLS) as a potential region participating in the effect of ejaculation on social fear extinction. In support, microdialysis experiments revealed a rise in OXT release within the LS, but not the amygdala, during mating. Finally, infusion of an OXT receptor antagonist into the LS before mating or into the lateral ventricle (icv) after mating demonstrated a significant role of brain OXT receptor-mediated signaling in the mating-induced facilitation of social fear extinction.
摘要：
在哺乳动物中,一些生理状况与高的脑催产素(OXT)系统活性有关。这些包括雌性的泌乳和雄性和雌性的交配，两者都与降低应激反应和抗焦虑有关。此外，在社交恐惧条件(SFC)的小鼠模型中，增强泌乳小鼠的脑OXT信号，特别是在侧隔（LS），据报道，这是社会恐惧表达减少的基础。这里,我们研究了雄性小鼠交配对焦虑相关行为的影响，社会（和暗示）恐惧表达及其灭绝，OXT神经元的活性由LS和杏仁核中的cFos表达和OXT释放反映。我们进一步关注大脑OXT参与交配诱导的社会恐惧灭绝的过程。我们可以证实雄性小鼠交配的抗焦虑作用，而与射精的发生无关。Further,我们发现，只有成功的交配导致射精（Ej+）促进社会恐惧灭绝，而没有射精的交配（Ej-）没有。相比之下,交配并不影响暗示恐惧的表达。使用细胞活性标记cFos和pErk，我们进一步确定腹侧LS(vLS)是参与射精对社会恐惧灭绝影响的潜在区域.支持,微透析实验揭示了LS内OXT释放的增加，但不是杏仁核,在交配期间。最后,交配前将OXT受体拮抗剂注入LS或交配后注入侧脑室（icv），这表明大脑OXT受体介导的信号传导在交配诱导的社交恐惧消退的促进中具有重要作用。
