[Pharmacologic characterization of alpha bungarotoxin binding sites on microcellular lung carcinoma cell lines].

Alpha Bungarotoxin binding protein belongs to the group of nicotinic receptors regarding their pharmacologic characteristics. Presence of alpha Bungarotoxin binding sites was confirmed on six cell lines of human microcellular lung carcinomas. The binding sites are saturable, specific and show high affinity for alpha Bungarotoxin. The presence of the binding sites was found on human microcellular lung carcinoma cultured in the mice of "Nude" clones. Using pharmacologically active substances like succinilcholine, decamethonium, atropine and propranolol, the nicotinic characteristics of alpha Bungarotoxin binding sites were confirmed. The presence of alpha 5 subunits in the alpha Bungarotoxin binding protein of human microcellular lung cells was established by Northern blot experiments classifying alpha Bungarotoxin binding protein on microcellular cells as a neuronal nicotinic receptor regarding its structure.