In this study, we examined whether the presence of mother suppresses early-life stressful social experience (SSE)-induced anxiety-like behavior and impairment of short-term memory later in life. On postnatal day (PND)-5, mothers with pups were grouped as follows: (i) control; (ii) maternal separation (MS); (iii) pups with mother experience the presence of a stranger (M+P-ST); and (iv) maternal separated pups experience the presence of a stranger (MSP-ST). Individuals were subjected to light-dark box and spontaneous alternation from PND-29 to 32. We observed that the MSP-ST group exhibits anxiety-like behavior and impairment in short-term memory. Further, SSE significantly elevated the adrenocorticotropic hormone, corticosterone and expression of glucocorticoid receptor (GR) in MSP-ST pups. Similarly, serotonin (5-hydroxytryptamine; 5-HT), dopamine, noradrenaline and expression of serotonin transporter levels were significantly elevated in MSP-ST pups. These observations suggest that during early postnatal days, the pups may recognize strangers by the sense of smell, and the presence of mother reduces the SSE-induced stress.
Dev Neurosci 2019;41:212–222

中文翻译：

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母亲的存在减轻了早期生活中的社会压力：将下丘脑-垂体-肾上腺轴的变化和血清素能系统联系起来。

在这项研究中，我们检查了母亲的存在是否能抑制生活早期的压力性社交经历（SSE）所引起的焦虑样行为，以及在生活后期对短期记忆的损害。在产后第5天（PND），将有幼崽的母亲分组如下：（i）对照；（ii）产妇分离（MS）；（iii）与母亲在一起的幼犬经历了一个陌生人的出现（M + P-ST）；（iv）产妇分开的幼崽经历了一个陌生人的出现（MSP-ST）。对个体进行明暗框显示，并从PND-29到32进行自发交替。我们观察到MSP-ST组表现出焦虑样行为，并在短期记忆中受损。此外，SSE显着提高了MSP-ST幼犬的促肾上腺皮质激素，皮质酮和糖皮质激素受体（GR）的表达。同样，血清素（5-羟色胺； 5-HT），多巴胺，在MSP-ST幼崽中，去甲肾上腺素和血清素转运蛋白的表达明显升高。这些观察结果表明，在产后早期，幼犬可能会通过嗅觉识别陌生人，而母亲的存在会减轻SSE诱发的压力。
Dev Neurosci 2019; 41：212–222