Clausing P, Mothes H K, Opitz B, Kormann S
Division of Neurotoxicology, National Center for Toxicological Research, Jefferson, AR 72079-9502, USA.
Behav Brain Res. 1997 Jan;82(2):179-84. doi: 10.1016/s0166-4328(97)80987-4.
On day 2 after delivery, dams of the DBA/1 mouse inbred strain (n = 20/group) with their litter were allocated to one of the following groups: NH21, nonhandling, housed 1 litter/cage, weaned on postnatal day (PND) 21;H21, handling, housed 1 litter/cage, weaned on PND 21; NH30, nonhandling, group-housed (5 litters/cage), weaned on PND 30; H30, handling, group-housed (5 litters/cage), weaned on PND 30. Two male pups of each litter were color marked on PND 2. From PND 8-21 they were removed from their cage, gently held in the experimenter's hand for 5 min/day. The two marked males of each litter were housed together after weaning, and tested in the open-field on PNDs 51-53, and one of each of these siblings was tested for hot-plate latencies on PND 54. Being raised in group-housing and weaned on PND 30 resulted in offspring exhibiting shorter latencies to initiate behavior and higher percentages of centerfield entries in the open field, hot-plate latencies, however, remained unaffected. Preweaning handling increased hot-plate latencies and the number of grooming episodes in the open field, and it decreased defecation, percent centerfield entries and open-field activity in general. It is concluded that the two forms of early experience have different effects on neurobehavioral endpoints 8 weeks after birth.
分娩后第2天，将DBA/1近交系小鼠（每组n = 20只）及其幼崽分配到以下组之一：NH21组，不处理，每笼饲养1窝幼崽，在出生后第21天断奶；H21组，处理，每笼饲养1窝幼崽，在出生后第21天断奶；NH30组，不处理，群居（每笼5窝），在出生后第30天断奶；H30组，处理，群居（每笼5窝），在出生后第30天断奶。在出生后第2天对每窝的两只雄性幼崽进行颜色标记。从出生后第8天至21天，将它们从笼中取出，每天在实验者手中轻轻握持5分钟。每窝的两只标记雄性幼崽在断奶后一起饲养，并在出生后第51天至53天在旷场中进行测试，其中每对同胞中的一只在出生后第54天进行热板潜伏期测试。在群居环境中饲养并在出生后第30天断奶导致后代在旷场中启动行为的潜伏期缩短，进入中央区域的百分比增加，然而，热板潜伏期不受影响。断奶前的处理增加了热板潜伏期和旷场中的梳理次数，并且总体上减少了排便、进入中央区域的百分比和旷场活动。得出的结论是，这两种早期经历形式对出生8周后的神经行为终点有不同影响。
