Wagner J A, Snowman A M, Biswas A, Olivera B M, Snyder S H
Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
J Neurosci. 1988 Sep;8(9):3354-9. doi: 10.1523/JNEUROSCI.08-09-03354.1988.
We describe unique, high-affinity binding sites for omega[125I]conotoxin GVIA in membranes from rat brain and rabbit sympathetic ganglia which appear to be primarily associated with N-type voltage-dependent calcium channels. The dissociation constant (KD) for the toxin in rat brain membranes is 60 pM. Physiologic extracellular concentrations of calcium inhibit toxin binding noncompetitively (IC50 = 0.2 mM). The regional distribution of the binding sites in rat brain differs markedly from that of dihydropyridine calcium antagonist receptors associated with L-type calcium channels. In detergent-solubilized brain membranes, toxin binding retains the same affinity, specificity, and ionic sensitivity as in particulate preparations.
我们描述了在大鼠脑和兔交感神经节细胞膜中存在的独特的、高亲和力的ω[¹²⁵I]芋螺毒素GVIA结合位点，这些位点似乎主要与N型电压依赖性钙通道相关。该毒素在大鼠脑膜中的解离常数（KD）为60 pM。生理细胞外钙浓度以非竞争性方式抑制毒素结合（IC50 = 0.2 mM）。大鼠脑中结合位点的区域分布与与L型钙通道相关的二氢吡啶钙拮抗剂受体的分布明显不同。在去污剂溶解的脑膜中，毒素结合与颗粒制剂中的结合具有相同的亲和力、特异性和离子敏感性。
