Luine V N, Spencer R L, McEwen B S
Department of Psychology, Hunter College, New York, NY 10021.
Brain Res. 1993 Jul 9;616(1-2):65-70. doi: 10.1016/0006-8993(93)90193-q.
The effects of chronic ingestion of corticosterone (8 weeks via the drinking water, 400 micrograms/ml) on spatial memory performance and on monoamine levels in brain areas related to memory were investigated. Corticosterone treatment was associated with a long lasting (5 weeks post treatment) increase in 5-HT levels (44%) in the dentate gyrus of the hippocampus and decrease in 5-HT (50%) and NE (36%) levels in the frontal cortex. No effects were found in CA1, CA3 or in nucleus basalis. Performance of the rats on an 8-arm radial arm maze showed no overall effect of corticosterone treatment on trials to criterion or choice accuracy scores. However, three of the treated rats, who had consumed the most corticosterone during treatment, 12.5 +/- 0.3 mg/day, were impaired relative to all subjects. Thus, these results suggest that hippocampal serotonergic terminals show long lasting effects from corticosterone and may also be an early indicator of deleterious effects of glucocorticoids on hippocampal function. However, since only a small number of corticosterone-treated rats showed behavioral changes, future experiments are necessary to address the possibility that a higher level of corticosterone intake alters spatial memory as well as brain morphology and neurochemistry. Additional studies are also needed to determine whether such changes represent a threshold effect of the steroid or a dose-response function.
研究了长期摄入皮质酮（通过饮用水持续8周，400微克/毫升）对空间记忆表现以及与记忆相关脑区单胺水平的影响。皮质酮处理与海马齿状回中5-羟色胺水平长期（处理后5周）升高（44%）以及额叶皮质中5-羟色胺（50%）和去甲肾上腺素（36%）水平降低有关。在CA1、CA3或基底核中未发现影响。大鼠在八臂放射状迷宫中的表现显示，皮质酮处理对达到标准的试验次数或选择准确性得分没有总体影响。然而，三只在处理期间摄入皮质酮最多（12.5±0.3毫克/天）的处理大鼠相对于所有受试者存在损伤。因此，这些结果表明，海马5-羟色胺能终末显示出皮质酮的长期影响，也可能是糖皮质激素对海马功能有害影响的早期指标。然而，由于只有少数接受皮质酮处理的大鼠出现行为变化，未来有必要进行实验，以探讨更高水平的皮质酮摄入是否会改变空间记忆以及脑形态和神经化学。还需要进一步的研究来确定这些变化是代表类固醇的阈值效应还是剂量反应函数。
