Department of Psychology, University of St. Thomas, 2115 Summit Ave, Saint Paul, MN, 55105, USA.
Behav Brain Res. 2021 May 7;405:113186. doi: 10.1016/j.bbr.2021.113186. Epub 2021 Feb 16.
Methamphetamine (MA) is a highly addictive psychomotor stimulant drug. Research has shown that the acute effects of MA can be modulated by age, although previous findings from our lab do not find age differences in the effects of MA. Relatively little research has examined the effects of adolescent MA exposure; thus, it is important to understand how MA affects adolescent behavior and brain function compared to adults. In order to better understand the age differences in the effects of acute MA exposure, this research examined the effects of MA exposure on locomotor and anxiety-like behavior and plasma corticosterone levels in adolescent and adult C57BL/6 J mice. Mice were exposed to saline, 2 mg/kg MA, or 4 mg/kg MA and behavior was measured in the open field test. Immediately following behavioral testing, serum was collected, and plasma corticosterone levels were measured. MA-exposed mice showed increased locomotor activity and anxiety-like behavior compared to saline controls, regardless of age and dose of MA. However, adolescent mice showed the greatest locomotor response to the high dose of MA (4 mg/kg), whereas the adult mice showed the greatest locomotor response to the low dose of MA (2 mg/kg). There were no differences in stereotyped behavior between the adolescent and adult mice exposed to the low dose of MA (2 mg/kg) and the high dose of MA (4 mg/kg). There was no effect of MA exposure on plasma corticosterone levels. These data suggest age modulates the locomotor response to MA and further research is warranted to determine the developmental neurobiological mechanism underlying the dose-response age differences in the response to acute MA exposure.
甲基苯丙胺（MA）是一种高度成瘾的精神兴奋剂药物。研究表明，MA 的急性效应可随年龄而变化，尽管我们实验室的先前研究结果并未发现 MA 效应存在年龄差异。相对较少的研究检查了青少年 MA 暴露的影响；因此，了解 MA 对青少年行为和大脑功能的影响与成人相比有何不同非常重要。为了更好地理解急性 MA 暴露的年龄差异，本研究检查了 MA 暴露对青少年和成年 C57BL/6J 小鼠的运动和焦虑样行为以及血浆皮质酮水平的影响。将小鼠暴露于生理盐水、2mg/kg MA 或 4mg/kg MA 中，并在开放场测试中测量行为。行为测试后立即采集血清，并测量血浆皮质酮水平。与生理盐水对照组相比，MA 暴露的小鼠表现出增加的运动活性和焦虑样行为，无论年龄和 MA 剂量如何。然而，青少年小鼠对高剂量 MA（4mg/kg）表现出最大的运动反应，而成年小鼠对低剂量 MA（2mg/kg）表现出最大的运动反应。在暴露于低剂量 MA（2mg/kg）和高剂量 MA（4mg/kg）的青少年和成年小鼠之间，刻板行为没有差异。MA 暴露对血浆皮质酮水平没有影响。这些数据表明年龄调节了对 MA 的运动反应，需要进一步研究以确定急性 MA 暴露反应中剂量-反应年龄差异的发育神经生物学机制。
