Chen M F, Chiu T H, Lee E H
Department of Physiology, National Yang-Ming Medical College, Taiwan, Republic of China.
Psychoneuroendocrinology. 1992 May-Jul;17(2-3):113-24. doi: 10.1016/0306-4530(92)90050-h.
A role for the locus coeruleus (LC) in attention and behavioral arousal has been suggested. The present study examined the effect of corticotropin-releasing factor (CRF) in the LC on memory retention of a passive-avoidance task in rats. Our results indicate that intra-LC CRF injection significantly improved retention performance. Decreases of norepinephrine (NE) levels in the hippocampus and the amygdala occurred in these animals. Intra-hippocampal 6-hydroxydopamine pretreatment did not affect memory alone, while it antagonized the memory-enhancing effect of CRF in the LC. This finding suggests that the dorsal NE pathway is involved in the memory consolidation process. Similar to the effect of CRF, application of the alpha 2-adrenergic antagonist yohimbine to the LC also dose-dependently enhanced memory, suggesting that CRF improved memory through activation of NE neurons in the LC. Finally, the anxiolytic chlordiazepoxide, at a concentration that did not alter memory by itself, prevented the memory-facilitating effect of CRF in the LC. Our findings suggest that the LC is an important structure in modulating learning and memory processes of passive avoidance learning in rats. CRF may enhance memory through activation of NE neurons in the LC and, at least in part, through the dorsal NE pathway. Furthermore, the LC is probably an anatomical substrate for anxiety and intra-LC CRF may enhance memory through its anxiogenic actions.
蓝斑（LC）在注意力和行为觉醒中的作用已被提出。本研究考察了蓝斑中促肾上腺皮质激素释放因子（CRF）对大鼠被动回避任务记忆保持的影响。我们的结果表明，向蓝斑内注射CRF显著改善了记忆表现。这些动物海马体和杏仁核中的去甲肾上腺素（NE）水平降低。海马体内预先注射6-羟基多巴胺单独并不影响记忆，但它拮抗了蓝斑中CRF的记忆增强作用。这一发现表明，背侧NE通路参与了记忆巩固过程。与CRF的作用相似，向蓝斑应用α2-肾上腺素能拮抗剂育亨宾也剂量依赖性地增强了记忆，这表明CRF通过激活蓝斑中的NE神经元来改善记忆。最后，抗焦虑药物氯氮卓在自身不改变记忆的浓度下，阻止了蓝斑中CRF的记忆促进作用。我们的研究结果表明，蓝斑是调节大鼠被动回避学习的学习和记忆过程的重要结构。CRF可能通过激活蓝斑中的NE神经元来增强记忆，并且至少部分地通过背侧NE通路。此外，蓝斑可能是焦虑的解剖学基础，蓝斑内的CRF可能通过其致焦虑作用来增强记忆。
