Gold Paul E
Neuroscience Program and Departments of Psychology and Psychiatry, University of Illinois at Urbana-Champaign, 603 East Daniel Street, Champaign, IL 61820, USA.
Neurobiol Aging. 2005 Dec;26 Suppl 1:60-4. doi: 10.1016/j.neurobiolaging.2005.09.002. Epub 2005 Oct 11.
Epinephrine, released from the adrenal medulla, enhances memory in young rats and mice and apparently does so, at least in part, by increasing blood glucose levels. Like epinephrine, administration of glucose enhances cognitive functions in humans and rodents, including reversing age-related impairments in learning and memory. Epinephrine responses to training are increased in aged rats but the subsequent increase in blood glucose levels is severely blunted. The absence of increases in blood glucose levels during training might contribute to age-related deficits in learning and memory. Also, extracellular glucose levels in the hippocampus are depleted during spontaneous alternation testing to a far greater extent in aged than in young rats. Importantly, systemic injections of glucose block the depletion in the hippocampus and also enhance performance on the alternation task. Thus, the extensive depletion of extracellular glucose during training in aged rats may be associated with age-related memory impairments, an effect that might be related to - or may exacerbate - the effects on learning and memory of an absence of the increases in blood glucose levels to training as seen in young rats. Together, these findings suggest that age-related changes in both peripheral and central glucose physiology contribute to age-related impairments in memory.
从肾上腺髓质释放的肾上腺素可增强幼鼠和小鼠的记忆力，而且显然至少部分是通过提高血糖水平来实现的。与肾上腺素一样，给予葡萄糖可增强人类和啮齿动物的认知功能，包括逆转与年龄相关的学习和记忆障碍。老年大鼠对训练的肾上腺素反应增强，但随后血糖水平的升高却严重减弱。训练期间血糖水平未升高可能导致与年龄相关的学习和记忆缺陷。此外，在自发交替测试期间，老年大鼠海马体中的细胞外葡萄糖水平耗竭程度远远大于幼鼠。重要的是，全身性注射葡萄糖可阻止海马体中的葡萄糖耗竭，还可提高交替任务的表现。因此，老年大鼠训练期间细胞外葡萄糖的大量耗竭可能与年龄相关的记忆障碍有关，这种影响可能与幼鼠训练时血糖水平未升高对学习和记忆的影响相关，或者可能会加剧这种影响。总之，这些发现表明，外周和中枢葡萄糖生理的年龄相关变化会导致与年龄相关的记忆障碍。
