Children exposed to methamphetamine (MA) in utero have cognitive deficits. MA administration in rats for 5–10 days between postnatal days (P)6 and 20 produces cognitive deficits. The purpose of this study was to determine if extending MA administration by 5 days within P6–20 would exacerbate allocentric (Morris water maze) and egocentric (Cincinnati water maze) learning deficits. Sprague Dawley female and male offspring (split‐litter design) were administered saline (SAL) or MA (10 mg/kg) four times daily from P6 to 20 to create four groups: (a) SAL from P6 to 20, (b) MA from P6 to 20 (MA6–20), (c) MA from P6 to 15 (MA6–15), or (d) MA from P11 to 20 (MA11–20); the latter groups received saline on days they did not receive MA. Egocentric, allocentric, and conditioned freezing tests began on P60. The MA6–15 and MA6–20 groups showed egocentric deficits, all MA groups had allocentric deficits but no differences in conditioned freezing compared with SAL controls. The MA6–15 and MA6–20 groups had similar deficits in learning and memory that were larger than in the MA11–20 group. Learning in both mazes was sex dependent, but no interactions with MA were found. The data demonstrate that extending the exposure period of MA beyond the sensitive periods (P6–15 and P11–20) did not exacerbate the cognitive deficits.

中文翻译：

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在新生 Sprague-Dawley 大鼠的关键时期长期接触甲基苯丙胺不会加剧以自我为中心和以异体为中心的学习缺陷，但会增加参考记忆障碍

在子宫内接触甲基苯丙胺 (MA) 的儿童存在认知缺陷。在出生后第 6 天和第 20 天之间给大鼠注射 MA 5-10 天会产生认知缺陷。本研究的目的是确定在 P6-20 内将 MA 给药延长 5 天是否会加剧异中心（莫里斯水迷宫）和以自我为中心（辛辛那提水迷宫）的学习缺陷。从 P6 到 20 每天四次给 Sprague Dawley 雌性和雄性后代（分窝设计）注射生理盐水 (SAL) 或 MA (10 mg/kg) 以创建四组：（a）从 P6 到 20 的 SAL，（b）从 P6 到 20 (MA6-20) 的 MA，(c) 从 P6 到 15 (MA6-15) 的 MA，或 (d) 从 P11 到 20 (MA11-20) 的 MA；后一组在未接受 MA 的日子接受生理盐水。以自我为中心、以异体为中心和有条件的冷冻测试从 P60 开始。MA6-15 和 MA6-20 组表现出自我中心缺陷，所有 MA 组都有异中心缺陷，但与 SAL 对照组相比，条件冷冻没有差异。MA6-15 和 MA6-20 组有类似的学习和记忆缺陷，但比 MA11-20 组更大。在两个迷宫中学习都依赖于性别，但没有发现与 MA 的相互作用。数据表明，延长 MA 的暴露期超过敏感期（P6-15 和 P11-20）不会加剧认知缺陷。