Two developmental stressors were compared in preweaning rats exposed to either one stressor or both. Stressors were barren cage rearing or maternal separation (pup isolation). 40 gravid Sprague-Dawley CD/IGS rats were randomly assigned to two cage conditions: standard (Std) cage or barren cage (Bar), 20 litters/condition throughout gestation and lactation. After delivery, litters were randomly culled to 4 males and 4 females. The second stressor was maternal separation: Two male/female pairs per litter were isolated from their dam 4 h/day (Iso) and two pairs were not (Norm). Hence, there were 4 conditions: Std-Norm, Std-Iso, Bar-Norm, and Bar-Iso. One pair/litter/stress condition received the following: elevated zero-maze (EZM), open-field, swim channel, Cincinnati water maze, conditioned fear, and open-field with methamphetamine challenge. The second pair/litter/condition received the light-dark test, swim channel, Morris water maze, forced swim, and EZM with diazepam challenge. Barren rearing reduced EZM time-in-open, whereas isolation rearing reduced open-field activity in males and increased it in females. Effects on straight channel swimming were minor. In the Cincinnati water maze test of egocentric learning, isolation rearing increased errors whereas barren cage housing reduced errors in combination with normal rearing. Barren cage with maternal separation (pup isolation) increased Cincinnati water maze escape latency but not errors. Barren cage housing reduced hyperactivity in response to methamphetamine. Isolation rearing increased time in open in the EZM after diazepam challenge. Trends were seen in the Morris water maze. These suggested that barren cage and isolation rearing in combination reduced latency on acquisition on days 1 and 2 in males, whereas females had increased latency on days 2 and 3. Combined exposure to two developmental stressors did not induce additive or synergistic effects, however the data show that these stressors had long-term effects with some evidence that the combination of both caused effects when either stressor alone did not, but synergism was not observed.

在暴露于一种压力源或两种压力源的断奶前大鼠中比较了两种发育压力源。压力源是荒笼饲养或母体分离（幼犬隔离）。40 只妊娠 Sprague-Dawley CD/IGS 大鼠被随机分配到两种笼子条件：标准 (Std) 笼子或贫瘠笼子 (Bar)，整个妊娠期和哺乳期 20 窝/条件。分娩后，每窝随机挑选4只雄性和4只雌性。第二个压力源是母体分离：每窝有两对雄性/雌性对从它们的大坝中分离出来，每天 4 小时 (Iso)，而两对则不是 (Norm)。因此，有 4 个条件：Std-Norm、Std-Iso、Bar-Norm 和 Bar-Iso。一对/窝/压力条件收到以下内容：高架零迷宫 (EZM)、开放场、游泳通道、辛辛那提水迷宫、条件恐惧和开放场与甲基苯丙胺挑战。第二对/窝/条件接受明暗测试、游泳通道、莫里斯水迷宫、强迫游泳和 EZM 与地西泮挑战。贫瘠饲养减少了 EZM 的开放时间，而隔离饲养减少了雄性的露天活动并增加了雌性的活动。对直通道游泳的影响很小。在以自我为中心的辛辛那提水迷宫测试中，隔离饲养增加了错误，而贫瘠的笼舍结合正常饲养减少了错误。母体分离（幼犬隔离）的贫瘠笼子增加了辛辛那提水迷宫逃生潜伏期，但没有增加错误。贫瘠的笼舍减少了对甲基苯丙胺的反应过度活跃。在地西泮攻击后，隔离饲养增加了 EZM 中的开放时间。在莫里斯水迷宫中可以看到趋势。