Such signaling may be mediated by the classical neurotransmitter serotonin (Lauweryns et al., 1973), but PNECs also produce γ-aminobutyric acid (GABA) (Schnorbusch et al., 2013) and several neuropeptides including calcitonin gene-related peptide (CGRP), which can signal locally to lung goblet (via GABA, γ-aminobutyric acid) and immune cells (via CGRP, calcitonin gene-related peptide) and may contribute to asthma (Barrios et al., 2019; Sui et al., 2018). The gene discussed is CALCA; the disease is asthma.