title: High-affinity binding of alpha-scorpion toxin: a neuronal property.
abstract: alpha-Scorpion toxin binding to its receptor--one component of the voltage-sensitive sodium channel--was studied in an attempt to define its phenotypic specificity. To this end we investigated the ability of neuronal, glial myogenic and fibroblastic cell lines to bind alpha-toxin II, purified from venom of the scorpion Androctonus australis Hector. A single class of saturable high-affinity (Kd congruent to 1 nM) binding sites, was present only in cell lines exhibiting some of the characteristics of normal neuronal cells, such as the N18, NIE-115, NS20, BN10-10, NG108-15 and T28 cell lines. NIA-103, which is an electrically non-excitable neuronal cell, gave negative results. In glial (G26-20, TR6B, C6) myogenic (T984) or fibroblastic (L) cell lines, we were unable to detect high-affinity binding sites for alpha-scorpion toxin. Primary cultures of rat skeletal muscle cells were also negative. Thus specific binding in the nanomolar range seems to be selectively associated with the neuronal phenotype. alpha-Scorpion toxin binding was tested before and after induction of neurites: in N18, NIE-115, NS20 cell lines, the differentiation brought on an increase in the number of binding sites but had little effect on the dissociation constant; in the hybrids NG108-15 and T28 high affinity saturable binding sites were detectable after but not prior to morphological differentiation.
mesh_terms: D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D002999:Clone Cells; D007739:L Cells; D051379:Mice; D009132:Muscles; D009374:Neoplasms, Experimental; D009447:Neuroblastoma; D009457:Neuroglia; D009474:Neurons / Q000378:metabolism*; D009489:Neurosecretion; D051381:Rats; D012604:Scorpion Venoms / Q000378:metabolism*; D013724:Teratoma
chemical_list: D012604:Scorpion Venoms