To elucidate whether the observed effect of denatonium on the transepithelial ion transport was dependent on BC-mediated paracrine cholinergic signalling, we applied mecamylamine (25 μM, apical and basolateral), a nAChR antagonist, in order to inhibit cholinergic signalling after the release of ACh from BC (Figure 6A). The gene discussed is CHRNA4; the disease is breast cancer.