Lonstein J S, Stern J M
Department of Psychology, Rutgers, The State University of New Jersey, New Brunswick, NJ 08903, USA.
Brain Res. 1998 Aug 31;804(1):21-35. doi: 10.1016/s0006-8993(98)00642-8.
Bilateral electrolytic lesions of the lateral and ventrolateral caudal periaqueductal gray (cPAGl,vl) of lactating rats are known to severely reduce suckling-induced kyphosis (upright crouched nursing), which is necessary for maximal litter weight gains, and impair sexual behavior during the postpartum estrous, while heightening nursing in other postures and attacks on unfamiliar adult male intruders. In the present report, the site specificity of the cPAG with respect to the control of these behaviors was determined by comparing lesions of the cPAGl,vl with similarly sized lesions within the rostral PAG (rPAG) and surrounding mesencephalon. The previously seen effects of prepartum cPAGl,vl lesions on kyphotic nursing, sexual proceptivity and receptivity, maternal aggression, and daily litter weight gains were replicated. Additionally, the post-lesion facilitation of aggression was found to be behaviorally specific, first by being directed toward an adult, but not to a nonthreatening juvenile male rat, and second, by requiring the recent presence of the pups, being eliminated or decreased 24 h after removal of the litter. Damage to the rPAG did not affect nursing or sexual behaviors, and had only a minimal effect on maternal aggression. Lesions of the rPAG, however, greatly impaired the dams' ability to rapidly release pups held in the mouth, but not to pick them up or carry them directly to the nest during retrieval. Separate regions of the PAG, therefore, are differentially involved in the control of specific components of behaviors in lactating rats.
已知对哺乳期大鼠尾侧导水管周围灰质外侧和腹外侧（cPAGl，vl）进行双侧电解损伤会严重降低哺乳引起的脊柱后凸（直立蹲伏式哺乳），而这种姿势对于窝仔最大体重增加是必要的，并且会损害产后发情期的性行为，同时增加其他姿势的哺乳行为以及对陌生成年雄性入侵者的攻击行为。在本报告中，通过比较cPAGl，vl损伤与 Rostral PAG（rPAG）和周围中脑内大小相似的损伤，确定了cPAG在控制这些行为方面的位点特异性。产前cPAGl，vl损伤对脊柱后凸式哺乳、性接受度和接受能力、母性行为攻击以及每日窝仔体重增加的先前观察到的影响得到了重复。此外，发现损伤后攻击行为的促进具有行为特异性，首先是针对成年大鼠，而不是对无威胁的幼年雄性大鼠，其次是需要幼崽最近在场，在取出窝仔24小时后这种行为被消除或减少。rPAG损伤不影响哺乳或性行为，对母性行为攻击只有最小的影响。然而，rPAG损伤极大地损害了母鼠迅速吐出含在口中幼崽的能力，但不影响在找回幼崽时捡起它们或直接将它们带回巢穴的能力。因此，PAG的不同区域在控制哺乳期大鼠行为的特定组成部分中发挥着不同的作用。
