Abstract

Extensive evidence indicates that noradrenergic activation is essentially involved in mediating the enhancing effects of emotional arousal on memory consolidation. Our current understanding of the neurobiological mechanisms underlying the memory-modulatory effects of the noradrenergic system is primarily based on pharmacological studies in rats, employing targeted administration of noradrenergic drugs into specific brain regions. However, the further delineation of the specific neural circuitry involved would benefit from experimental tools that are currently more readily available in mice. Previous studies have not, as yet, investigated the effect of noradrenergic enhancement of memory in mice, which show different cognitive abilities and higher endogenous arousal levels induced by a training experience compared to rats. In the present study, we investigated the effect of posttraining noradrenergic activation in male C57BL/6J mice on the consolidation of object recognition and object location memory. We found that the noradrenergic stimulant yohimbine (0.3 or 1.0 mg/kg) administered systemically immediately after an object training experience dose-dependently enhanced 24-h memory of both the identity and location of the object. Thus, these findings indicate that noradrenergic activation also enhances memory consolidation processes in mice, paving the way for a systematic investigation of the neural circuitry underlying these emotional arousal effects on memory.

LAY SUMMARY: The current study successfully validated the effect of noradrenergic activation on both object recognition and object location memory in mice. This study thereby provides a fundamental proof-of-principle for the investigation of the neural circuitry underlying noradrenergic and arousal effects on long-term memory in mice.

摘要

大量证据表明，去甲肾上腺素能激活实质上参与了情绪唤起对记忆巩固的增强作用。我们目前对去甲肾上腺素系统记忆调节作用背后的神经生物学机制的理解主要是基于大鼠的药理研究，将去甲肾上腺素能药物定向给药到特定的大脑区域。但是，所涉及的特定神经回路的进一步描述将受益于目前在小鼠中更容易获得的实验工具。迄今为止，先前的研究尚未研究过去甲肾上腺素能增强小鼠记忆力的作用，与老鼠相比，它们显示出不同的认知能力和训练经验所诱发的更高的内源性唤醒水平。在目前的研究中，我们研究了雄性C57BL / 6J小鼠中训练后的去甲肾上腺素能激活对巩固目标识别和目标位置记忆的影响。我们发现，在对象训练后立即立即全身给药的去甲肾上腺素能刺激性育亨宾（0.3或1.0 mg / kg）剂量依赖性地增强了对象的身份和位置的24小时记忆。因此，这些发现表明，去甲肾上腺素能激活还增强了小鼠的记忆巩固过程，为系统研究这些情绪唤醒对记忆的潜在神经系统铺平了道路。（0 mg / kg）对象训练后立即立即全身给药，可以剂量依赖性地增强对象的身份和位置的24小时记忆。因此，这些发现表明，去甲肾上腺素能激活还增强了小鼠的记忆巩固过程，为系统研究这些情绪唤醒对记忆的潜在神经系统铺平了道路。（0 mg / kg）对象训练后立即立即全身给药，可以剂量依赖性地增强对象的身份和位置的24小时记忆。因此，这些发现表明，去甲肾上腺素能激活还增强了小鼠的记忆巩固过程，为系统研究这些情绪唤醒对记忆的潜在神经系统铺平了道路。

概述：当前的研究成功验证了去甲肾上腺素能激活对小鼠物体识别和物体位置记忆的影响。因此，这项研究为研究去甲肾上腺素能和唤醒效应对小鼠长期记忆的潜在神经回路提供了基本的原理证明。