Meyer E M, Cooper J R
J Neurosci. 1983 May;3(5):987-94. doi: 10.1523/JNEUROSCI.03-05-00987.1983.
Proteoliposomes were prepared from rat cortical synaptic plasma membranes that retained high and low affinity choline transport. High affinity transport was inhibited by hemicholinium-3 in a competitive manner and was apparently dependent on membrane potential or ion gradients. Proteoliposomes supplemented with an acetylcholine-generating system were able to synthesize [3H]ACh de novo from [3H]choline taken up by high or low affinity transport; however, we were able to specifically load proteoliposomes derived from cholinergic membranes by using a low choline concentration. [3H]ACh, but not [3H]choline, was subsequently released in a calcium-dependent manner by K+ depolarization. This preparation offers a simplified membrane system for studying functional high affinity choline transport and nonvesicular ACh release.
蛋白脂质体是由保留高亲和力和低亲和力胆碱转运的大鼠皮质突触质膜制备而成。高亲和力转运以竞争性方式被半胱氨酸-3抑制，并且显然依赖于膜电位或离子梯度。补充有乙酰胆碱生成系统的蛋白脂质体能够从通过高亲和力或低亲和力转运摄取的[3H]胆碱中重新合成[3H]乙酰胆碱；然而，我们能够通过使用低胆碱浓度特异性地装载源自胆碱能膜的蛋白脂质体。随后，[3H]乙酰胆碱而非[3H]胆碱通过钾离子去极化以钙依赖的方式释放。这种制备方法为研究功能性高亲和力胆碱转运和非囊泡性乙酰胆碱释放提供了一种简化的膜系统。
