In addition, nicotine stimulates the release of serotonin and the proliferation of SCLC in vitro, which can be blocked by α-bungarotoxin (α-Bgt), indicating that α7nAChR is critical in the process of nicotine absorption, promoting the secretion of related endogenous neurotransmitters and mitosis (Codignola et al., 1994). Here, CHRNA7 is linked to small cell lung carcinoma.