title: Photoaffinity labeling of scorpion toxin receptors associated with insect synaptosomal Na+ channels.
abstract: Photoreactive and radioiodinated derivatives of several scorpion toxins acting on insect Na+ channels were prepared without loss of their pharmacological activities. Photoaffinity experiments were carried out on a synaptosomal fraction from the nerve cord of the cockroach Periplaneta americana: with all toxin derivatives, a single specifically labeled band was obtained with a molecular weight of 188,000 +/- 12,000 (n = 17). These results indicate for the first time the molecular weight of the scorpion toxin receptor from the insect nervous system which is probably associated with voltage sensitive Na+ channels. One of these toxins, toxin VII from Tityus serrulatus venom, has been previously shown to be active both in mammals and in insects, in rat brain synaptosomes this toxin labeled a Mr = 31,000 +/- 4,000 band in contrast, to observations in the insect preparation.
mesh_terms: D000345:Affinity Labels; D000818:Animals; D007473:Ion Channels / Q000378:metabolism*; D008970:Molecular Weight; D010526:Periplaneta; D051381:Rats; D011950:Receptors, Cholinergic / Q000378:metabolism*; D012604:Scorpion Venoms / Q000378:metabolism*; D012605:Scorpions; D012964:Sodium / Q000378:metabolism*; D015222:Sodium Channels; D013574:Synaptosomes / Q000378:metabolism*
chemical_list: D000345:Affinity Labels; D007473:Ion Channels; D011950:Receptors, Cholinergic; D012604:Scorpion Venoms; D015222:Sodium Channels; C029574:scorpion toxin receptor; D012964:Sodium