Characterization of Na+-independent GABA and flunitrazepam binding sites in preparations of synaptic membranes and postsynaptic densities isolated from canine cerebral cortex and cerebellum.
Characterization of Na+-independent GABA and flunitrazepam binding sites in preparations of synaptic membranes and postsynaptic densities isolated from canine cerebral cortex and cerebellum.
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从犬大脑皮层和小脑分离的突触膜和突触后密度制剂中 Na 不依赖的 GABA 和氟硝西泮结合位点的表征。
DOI：
10.1111/j.1471-4159.1984.tb12837.x
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发表时间：
1984
影响因子：
4.7
通讯作者：
Siekevitz,P
中科院分区：
文献类型：
--
作者：
Carlin,RK;Siekevitz,P
[~ 3 H]GABA和[~ 3 H]氟硝西泮与从犬大脑皮层和小脑分离的突触膜和突触后致密物（PSD）进行结合。两个GABA结合位点被发现与大脑皮质膜，但只有一个与小脑膜。从这些分离的PSD显示只有单一的结合位点，与小脑PSD表现出较低的KD值和更大的浓度的网站比大脑皮层PSD。在氟硝西泮的情况下，只有一个结合位点，发现所有四个制剂，与小脑PSD的两倍，大脑PSD的网站的浓度。在两种情况下，PSD中氟硝西泮受体的光亲和标记导致与51，000 Mr蛋白质结合，小脑PSD再次显示出比大脑皮层PSD中发现的浓度增加。基于这项工作，以及我们自己和其他人的早期工作，我们得出结论，两种分离的PSD群体都含有抑制位点，但两种制备物中完整的PSD都来自Gray I型，可能是兴奋性突触，而抑制位点存在于PSD组分中的破碎物质中，这些PSD组分来自Gray II型，可能是抑制性突触。
The binding of [3H]GABA and [3H]flunitrazepam was performed with synaptic membranes and postsynaptic densities (PSDs) isolated from canine cerebral cortex and cerebellum. Two GABA binding sites were found with cerebral cortex membranes but only one with cerebellar membranes. PSDs isolated from these showed only single binding sites, with cerebellar PSDs exhibiting lowerKDvalues and a larger concentration of sites than did cerebral cortex PSDs. In the case of flunitrazepam, only one binding site was found for all four preparations, with cerebellar PSDs having twice the concentration of sites of cerebral PSDs. Photoaffinity labeling of the flunitrazepam receptor in PSDs resulted in the binding to a 51,000 Mrprotein in both cases, with cerebellar PSDs again showing an increased concentration over that found in cerebral cortex PSDs. Based on this work, and on earlier work of ourselves and of others, we conclude that both populations of isolated PSDs contain inhibitory sites, but that the intact PSDs in both preparations are derived from Gray type I, probably excitatory, synapses, and that the inhibitory sites are found in the broken‐up material in the PSD fractions which are derived from Gray type II, probably inhibitory, synapses.