SEROTONIN RELEASE AND CELL-PROLIFERATION ARE UNDER THE CONTROL OF ALPHA-BUNGAROTOXIN-SENSITIVE NICOTINIC RECEPTORS IN SMALL-CELL LUNG-CARCINOMA CELL-LINES

Neuronal type nicotinic acetylcholine receptors (nAchRs) have recently been identified in small-cell lung carcinoma. We here show that both nicotine and cytisine stimulate H-3serotonin release in a dose-depen dent manner; this effect is antagonized by alpha-bungarotoxin (alpha B gtx) and alpha-conotoxin MI (alpha Ctx). Nicotine and cytisine stimula te in vitro SCLC proliferation and this effect is completely antagoniz ed by both alpha Bgtx and alpha Ctx. By PCR analysis, we demonstrate t he presence in SCLC of both the alpha(7) and the beta(2) nAchR subunit s mRNA. These data show that nAchRs play an important role in the biol ogy of SCLC, and that alpha Bgtx-sensitive receptors of the alpha(7) s ubtype are crucially involved in both the secretagogue and mitogenic e ffects of nicotinic agonists.