Koshimura K, Miwa S, Lee K, Hayashi Y, Hasegawa H, Hamahata K, Fujiwara M, Kimura M, Itokawa Y
Department of Pharmacology, Kyoto University Faculty of Medicine, Japan.
J Neurochem. 1990 Feb;54(2):533-9. doi: 10.1111/j.1471-4159.1990.tb01904.x.
The purpose of the present study is to clarify the effects of the administration of choline on the in vivo release and biosynthesis of acetylcholine (ACh) in the brain. For this purpose, the changes in the extracellular concentration of choline and ACh in the rat striatum following intracerebroventricular administration of choline were determined using brain microdialysis. We also determined changes in the tissue content of choline and ACh. When the striatum was dialyzed with Ringer solution containing 10 microM physostigmine, ACh levels in dialysates rapidly and dose dependently increased following administration of various doses of choline and reached a maximum within 20 min. In contrast, choline levels in dialysates increased after a lag period of 20 min following the administration. When the striatum was dialyzed with physostigmine-free Ringer solution, ACh could not be detected in dialysates both before and even after choline administration. After addition of hemicholinium-3 to the perfusion fluid, the choline-induced increase in ACh levels in dialysates was abolished. Following administration of choline, the tissue content of choline and ACh increased within 20 min. These results suggest that administered choline is rapidly taken up into the intracellular compartment of the cholinergic neurons, where it enhances both the release and the biosynthesis of ACh.
本研究的目的是阐明给予胆碱对脑内乙酰胆碱（ACh）的体内释放和生物合成的影响。为此，使用脑微透析法测定脑室注射胆碱后大鼠纹状体内胆碱和ACh的细胞外浓度变化。我们还测定了胆碱和ACh的组织含量变化。当用含10微摩尔毒扁豆碱的林格液对纹状体进行透析时，给予不同剂量的胆碱后，透析液中的ACh水平迅速且呈剂量依赖性升高，并在20分钟内达到最大值。相比之下，透析液中的胆碱水平在给药后20分钟的延迟期后升高。当用不含毒扁豆碱的林格液对纹状体进行透析时，在胆碱给药前及给药后透析液中均未检测到ACh。向灌注液中加入半胱氨酸-3后，胆碱诱导的透析液中ACh水平升高被消除。给予胆碱后，胆碱和ACh的组织含量在20分钟内增加。这些结果表明，给予的胆碱迅速被胆碱能神经元的细胞内区摄取，在那里它增强了ACh的释放和生物合成。
