(A) Fluorescence changes in response to 10 μM SubP and 10 μM carbachol. Cell diameters in images are approximately 20 microns. (B) [Ca²⁺]_i versus time for 10 cells from images in A, measured in response to sequential pulses of 10 μM SubP and 10 μM carbachol. (C) [Ca²⁺]_i versus time for 10 cells from images in A, measured in response to sequential pulses of 10 μM SubP without and with 5 μM atropine (Atr). Fluorescence ratio, 340 nm/380 nm. (D) Mean response to SubP in presence or absence of BAPTA-AM (500 μM); 4 experiments from 2 HN and 1 DC subjects (16–20 glands). Error bars are SEM. (E) Mean response to SubP in the absence and presence of clotrimazole (25 μM), which blocks Ca²⁺-activated K⁺ channels (n = 4, 27–42 glands). *P < 0.05 versus SubP responses. Error bars are SEM.