Bubna-Littitz H
Institut für Physiologie der Veterinärmedizinischen Universität Wien.
Z Gerontol. 1988 Mar-Apr;21(2):93-101.
One possible cause of the decline in brain function with aging might be an age-related change in the blood-brain barrier (BBB). Therefore, we assessed the "Brain Uptake Index" (BUI) by the method of Oldendorf (1970) in 99 male Sprague-Dawley rats aged 3-4 months (young), 7-11 months (adult) and 28-31 months (old) for the following compounds: methionine, lysine, glutamic acid and N-methyl-N-nitrosourea (MNU). The BUIs of methionine and MNU showed marked but contrasting biphasic changes with age: the adult animals had the highest BUIs for methionine and the lowest for MNU, compared with the young and old groups. With lysine, a declining tendency with age was indicated, whereas no differences could be detected with glutamic acid. The results suggest that the BBB undergoes different changes in development and aging, leading to an optimal amino acid transport and minimum penetration of lipophilic agents (MNU) in the adult brain. Thereafter, the opposite takes place, reducing necessary transport and increasing the penetration of lipophilic compounds.
脑功能随年龄增长而衰退的一个可能原因或许是血脑屏障（BBB）的年龄相关变化。因此，我们采用奥尔登多夫（1970年）的方法，对99只3至4个月大（年轻）、7至11个月大（成年）和28至31个月大（老年）的雄性斯普拉格-道利大鼠进行了“脑摄取指数”（BUI）评估，所涉及的化合物有：蛋氨酸、赖氨酸、谷氨酸和N-甲基-N-亚硝基脲（MNU）。蛋氨酸和MNU的BUI呈现出明显但相反的双相年龄变化：与年轻组和老年组相比，成年动物蛋氨酸的BUI最高，而MNU的BUI最低。对于赖氨酸，显示出随年龄下降的趋势，而对于谷氨酸则未检测到差异。结果表明，血脑屏障在发育和衰老过程中经历不同变化，导致成年大脑中氨基酸转运达到最佳状态，亲脂性物质（MNU）的渗透降至最低。此后，情况相反，必需转运减少，亲脂性化合物的渗透增加。
