Serotonin release and cell proliferation are under the control of α‐bungarotoxin‐sensitive nicotinic receptors in small‐cell lung carcinoma cell lines

Abstract
Neuronal type nicotinic acetylcholine receptors (nAchRs) have recently been identified in small-cell lung carcinoma. We here show that both nicotine and cytisine stimulate [ 3 H]serotonin release in a dose-dependent manner; this effect is antagonized by α-bungarotoxin (αBgtx) and α-conotoxin MI (αCtx). Nicotine and cytisine stimulate in vitro SCLC proliferation and this effect is completely antagonized by both αBgtx and αCtx. By PCR analysis, we demonstrate the presence in SCLC of both the α 7 and the β 2 nAchR subunits mRNA. These data show that nAchRs play an important role in the biology of SCLC, and that αBgtx-sensitive receptors of the α 7 subtype are crucially involved in both the secretagogue and mitogenic effects of nicotinic agonists.