Salas Manuel, Regalado Mirelta, Torrero Carmen, Rubio Lorena
Department of Developmental Neurobiology and Neurophysiology, Institute of Neurobiology, Universidad Nacional Autonoma de Mexico, Mexico.
Department of Developmental Neurobiology and Neurophysiology, Institute of Neurobiology, Universidad Nacional Autonoma de Mexico, Mexico.
Int J Dev Neurosci. 2017 Nov;62:25-31. doi: 10.1016/j.ijdevneu.2017.07.005. Epub 2017 Jul 29.
The expression of different behavioral components in the adult rat depends on a number of early influences, including age, hormones, manipulations of sensory cues, and perinatal undernutrition, all of which impact the development of brain areas underlying adaptive processes, maternal behavior, and the response to novelty. The current study investigates the effects of pre- and neonatal undernutrition on various components of maternal behavior of dams exposed to the challenge of an unfamiliar home cage on days 4, 8, and 12 of lactation. Food restriction was initiated from gestational day (G) G6 to G19 when dams received 50-70% of the normal balanced diet, followed by 100% from G20 to G21. After birth, pups were underfed by alternating every 12h between two lactating dams, one of which, had ligated nipples. Weaning was at 25days of age followed by an ad libitum diet until postpartum day 90, when females were mated, and subsequently tested for maternal behavior in an unfamiliar cage. The results indicated that in early underfed mothers the frequency of handling wood shavings and of, approaching, licking, crouching, and grasping pups for retrieval was significantly reduced. Moreover, self-grooming increased substantially in the underfed dams, but the frequency of rearing was reduced. Additionally, the body weight of pups nursed by early underfed dams was significantly lower than that of control pups. These findings suggest a relation between early food restriction and the deficient maternal care observed when these dams were challenged by exposure to an unfamiliar home cage.
成年大鼠不同行为成分的表达取决于多种早期影响因素，包括年龄、激素、感觉线索的操控以及围产期营养不良，所有这些都会影响适应性过程、母性行为及对新事物反应背后的脑区发育。本研究调查了产前和新生儿期营养不良对在哺乳期第4、8和12天面临陌生饲养笼挑战的母鼠各种母性行为成分的影响。从妊娠第6天（G6）至G19开始限制食物，在此期间母鼠仅获得正常均衡饮食的50 - 70%，从G20至G21则给予100%的正常饮食。出生后，幼崽每12小时在两只哺乳母鼠之间交替哺乳，其中一只母鼠的乳头已结扎，以此使幼崽摄入不足。幼崽在25日龄断奶，之后自由进食直至产后第90天，此时雌性母鼠进行交配，随后在陌生笼子中测试其母性行为。结果表明，早期营养不足的母鼠处理木屑、接近、舔舐、蹲伏以及抓取幼崽以便找回的频率显著降低。此外，营养不足的母鼠自我梳理行为大幅增加，但直立行为的频率降低。另外，由早期营养不足的母鼠哺育的幼崽体重显著低于对照组幼崽。这些发现表明早期食物限制与当这些母鼠面临陌生饲养笼挑战时所观察到的母性关怀不足之间存在关联。
