The preoptic area (POA) is a brain structure classically involved in a wide variety of animal behavior including sleep and maternal care. In the current study, we evaluate the specific effect of disinhibition of two specific regions of the POA, the medial POA nucleus (mPOA) and the ventrolateral POA area (VLPO) on sleep and maternal behavior in lactating rats. For this purpose, mother rats on postpartum day 1 (PPD1) were implanted for polysomnographic recordings and with bilateral cannulae either in the mPOA or in the VLPO. The rats were tested for sleep and maternal behavior on PPD4–8 after the infusion of the GABA-A antagonist, bicuculline (0, 10 or 30 ng/0.2 µl/side). Infusion of bicuculline into the mPOA augmented retrieving and nest building behaviors and reduced both nursing and milk ejections but had almost no effect on sleep. When bicuculine was microinjected into the VLPO, the rats significantly increase the number of retrievings and mouthings and reduced the nursing time without changes in milk ejections, which was associated with an increase in wakefulness and a reduction in light sleep.

Our results show that disinhibition of the mPOA, a key area in the control of maternal behavior, increased active maternal behaviors and reduced nursing without affecting wakefulness or sleep time. In contrast, the enhancement of some active maternal behaviors when the drug was infused into the VLPO, a sleep-promoting area, with a concomitant increase in wakefulness suggests that mother rats devote this additional waking time in the active maternal care of the pups. We hypothesize that maternal behavior changes after bicuculine microinjection into the VLPO are caused by a reduction in the sleep drive, rather than a direct effect on maternal behavior.

视前区 (POA) 是一种大脑结构，经典地涉及各种动物行为，包括睡眠和母体护理。在目前的研究中，我们评估了 POA 的两个特定区域，内侧 POA 核 (mPOA) 和腹外侧 POA 区 (VLPO) 的去抑制对哺乳期大鼠睡眠和母体行为的具体影响。为此，在产后第 1 天 (PPD1) 植入母鼠进行多导睡眠图记录，并在 mPOA 或 VLPO 中植入双侧套管。在输注 GABA-A 拮抗剂荷包牡丹碱（0、10 或 30 ng/0.2 µl/侧）后，对大鼠的睡眠和母体行为进行了 PPD4-8 测试。将荷包牡丹碱注入 mPOA 增强了检索和筑巢行为，并减少了哺乳和泌乳，但对睡眠几乎没有影响。

我们的结果表明，mPOA 的去抑制是控制母亲行为的一个关键领域，可以增加积极的母亲行为并减少护理，而不会影响清醒或睡眠时间。相比之下，当药物注入 VLPO（一个促进睡眠的区域）时，一些活跃的母性行为的增强，伴随着觉醒的增加，表明母鼠将这段额外的清醒时间用于积极的母性照顾幼崽。我们假设荷包牡丹碱显微注射到 VLPO 后母亲的行为变化是由睡眠驱动的减少引起的，而不是对母亲行为的直接影响。