Pelchen-Matthews A, Dolly J O
Department of Biochemistry, Imperial College of Science and Technology, London, U.K.
Neuroscience. 1989;29(2):347-61. doi: 10.1016/0306-4522(89)90062-6.
Dendrotoxin, a snake polypeptide that facilitates the release of neurotransmitters, is a putative ligand for certain voltage-dependent, rapidly-activating K+ channels. Using a 125I-labelled derivative, the location of high-affinity acceptors for this toxin in the rat central nervous system was established by quantitative sheet film autoradiography. A widespread distribution of binding sites was observed, with high densities of acceptors being found in most gray matter regions and along nerve tracts. Heterogeneity in these acceptors was deduced from their differential interaction with beta-bungarotoxin, another probe that perturbs transmitter release. Whereas the latter blocked the majority of dendrotoxin sites in gray matter areas, it competed much less efficaciously for the acceptors in white matter. These collective findings demonstrate the occurrence of dendrotoxin acceptor sub-types which display characteristic distributions in the central nervous system. Notably, this heterogeneity can be related to electrophysiological evidence for the presence in neurons of multiple, dendrotoxin-sensitive, K+ conductances, though some of these remain to be shown directly in brain preparations.
树突毒素是一种促进神经递质释放的蛇多肽，是某些电压依赖性、快速激活的钾通道的一种假定配体。使用一种125I标记的衍生物，通过定量薄片放射自显影术确定了该毒素在大鼠中枢神经系统中高亲和力受体的位置。观察到结合位点分布广泛，在大多数灰质区域和神经束中发现了高密度的受体。这些受体的异质性是从它们与另一种干扰递质释放的探针——β-银环蛇毒素的不同相互作用推断出来的。后者阻断了灰质区域中的大多数树突毒素位点，但在白质中与受体竞争的效率要低得多。这些共同的发现证明了树突毒素受体亚型的存在，它们在中枢神经系统中表现出特征性分布。值得注意的是，这种异质性可能与神经元中存在多种对树突毒素敏感的钾电导的电生理证据有关，尽管其中一些仍有待在脑标本中直接证明。
