青少年和成年大鼠中甲基苯丙胺自我给药的升级。
Escalation of methamphetamine self-administration in adolescent and adult rats.
机构信息
Department of Psychiatry, University of Minnesota, MMC 392, Minneapolis, MN 55455, USA.
出版信息
Drug Alcohol Depend. 2012 Jul 1;124(1-2):149-53. doi: 10.1016/j.drugalcdep.2012.01.004. Epub 2012 Feb 2.
BACKGROUND
Methamphetamine (METH) use has increased substantially in the last 10 years and poses a serious health concern, especially for young populations. Drug abuse primarily begins during adolescence, when uninhibited and excessive and drug intake is a common occurrence; thus, understanding the developmental patterns of addiction during this critical period is an essential step in its prevention. In the present study, the effect of age on the vulnerability to METH abuse was examined using a rat model of bingeing (i.e., escalation).
METHODS
Adolescent and adult rats were compared during short (ShA, 2-h) and long-access (LgA, 6-h) to METH self-administration. On postnatal (PN) days 23 (adolescents) and 90 (adults), rats were implanted with i.v. catheters and trained to lever press for infusions of METH (0.05mg/kg) during 2-h sessions. Once the rats reached a steady rate of METH self-administration, they were divided into ShA or LgA groups and allowed to self-administer METH for 15 additional days.
RESULTS
Results indicated that adolescent rats earned significantly more infusions than adults under the LgA condition, but the age groups did not differ during ShA. Adolescents, but not adults, also significantly increased (i.e., escalated) METH self-administration across the 15 days of testing under the LgA condition. Further analysis indicated excessive responding during infusions in the LgA METH-exposed adolescents compared to the other groups, suggesting elevated impulsivity or motivation for drug.
CONCLUSION
These results demonstrate that adolescents are more vulnerable to the escalation of METH than adults during LgA.
背景
在过去的 10 年中，甲基苯丙胺（METH）的使用量大幅增加，对年轻人的健康构成了严重威胁。药物滥用主要始于青春期，此时青少年不受约束地过度摄入药物是很常见的；因此，了解这一关键时期成瘾的发展模式是预防的重要步骤。在本研究中，使用 bingeing（即升级）的大鼠模型检查了年龄对 METH 滥用易感性的影响。
方法
比较了青少年和成年大鼠在短（ShA，2 小时）和长（LgA，6 小时）接触 METH 自我给药期间的情况。在出生后（PN）第 23 天（青少年）和第 90 天（成年），大鼠被植入静脉导管，并在 2 小时的疗程中接受 METH 输注的杠杆按压训练。一旦大鼠达到稳定的 METH 自我给药率，它们被分为 ShA 或 LgA 组，并允许在接下来的 15 天内自行服用 METH。
结果
结果表明，在 LgA 条件下，青少年大鼠的输液次数明显多于成年大鼠，但在 ShA 条件下，两组年龄组之间没有差异。在 LgA 条件下，青少年也显著增加（即升级）了 15 天的 METH 自我给药。进一步的分析表明，与其他组相比，在 LgA 暴露的青少年中，在输液期间过度反应，这表明冲动或对药物的动机增强。
结论
这些结果表明，与成年大鼠相比，青少年在 LgA 时更容易升级 METH。
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