Kasarskis E J
Exp Neurol. 1984 Jul;85(1):114-27. doi: 10.1016/0014-4886(84)90166-3.
Zinc uptake and turnover was measured in nine brain regions, choroid plexus, arachnoid, and cerebrospinal fluid during a 28-day period following a single dose of 65Zn in rats fed Zn-adequate diets. Zinc entry into brain was slow with maximal 65Zn uptake (0.5% of administered dose) occurring between 5 and 14 days in contrast to its rapid metabolism in plasma and nonneural tissues. The brain stem, at the level of the caudal IV ventricle, had the highest rate of initial 65Zn uptake of any brain region. In general, turnover was most rapid in periventricular regions and least in the hippocampus. Relative to plasma, the choroid plexus concentrated 65Zn whereas 65Zn was undetectable in the cerebrospinal fluid after day 1. To determine if specific brain regions were particularly sensitive to changes in Zn status, 65Zn metabolism was measured in Zn-deficient rats and compared with ad libitum- and pair-fed controls. Zinc deficiency was associated with increased 65Zn retention by all brain regions; however, the effect was greatest in optic nerve and choroid plexus. The results of this study suggest that a formidable barrier to Zn entry into brain exists but is under homeostatic control, increasing net Zn uptake during dietary deficiency. Moreover, the choroid plexus may participate in cerebral Zn homeostasis, possibly by transporting Zn out of the cerebrospinal fluid compartment.
在给喂食锌充足日粮的大鼠单次注射65Zn后的28天期间，测定了九个脑区、脉络丛、蛛网膜和脑脊液中的锌摄取和周转情况。锌进入大脑的速度较慢，最大65Zn摄取量（占给药剂量的0.5%）在5至14天之间出现，这与其在血浆和非神经组织中的快速代谢形成对比。在尾侧第四脑室水平的脑干，是所有脑区中初始65Zn摄取率最高的。一般来说，脑室周围区域的周转最快，海马体中的周转最慢。相对于血浆，脉络丛浓缩65Zn，而在第1天后脑脊液中检测不到65Zn。为了确定特定脑区是否对锌状态的变化特别敏感，在缺锌大鼠中测量了65Zn代谢，并与随意进食和配对喂养的对照组进行了比较。锌缺乏与所有脑区65Zn保留增加有关；然而，对视神经和脉络丛的影响最大。这项研究的结果表明，锌进入大脑存在一个巨大的障碍，但处于稳态控制之下，在饮食缺乏期间会增加锌的净摄取。此外，脉络丛可能参与大脑锌稳态，可能是通过将锌从脑脊液隔室中转运出来。
