Figure 5. Effects of VIP and carbachol on [Ca²⁺]_i in lacrimal gland duct cells from WT and CFTR KO mice. A: Representative recordings of the microfluorescence experiments: Effects of vasoactive intestinal peptide (VIP; 100 nM) on [Ca²⁺]_i in lacrimal gland duct cells from wild-type (WT) and cystic fibrosis transmembrane conductance regulator (CFTR) knockout (KO) mice (panel A, left curve). Carbachol (100 µM) was used for comparison, as a positive control, in these experiments (panel A, right curve). F_380/340: 380/340 nm fluorescence emission ratio. B: Maximum values of the 380/340 nm fluorescence emission ratios. F_max(380/340): maximum value of the 380/340 nm fluorescence emission ratio.