Figure 7. Effects of a K⁺ channel blocker (quinine) and a Cl⁻ channel blocker (NPPB) on ACh-evoked exocytotic events and cell shrinkage.

V/V₀ is denoted by ○, and the frequency of exocytotic events is denoted by •. A, quinine at 1 mM evoked cell swelling in unstimulated antral mucous cells. ACh stimulation evoked further cell swelling and no exocytotic events (n = 5). B, NPPB at 20 μM evoked cell swelling in unstimulated antral mucous cells. ACh stimulation evoked cell shrinkage and exocytotic events. However, the extent of cell shrinkage and the number of exocytotic events were reduced compared with those in control experiments (n = 4).