Fig. 6
Effects of 5(N,N)-dimethyl amiloride (DMA) and its combination with diphenylamine-2-carboxylate (DPC) or methazolamide on carbachol (CCh)-induced pHi changes. a A time course of pHi change during the applications of DMA and DMA + CCh. The pHi was decreased by the addition of 20 μM DMA and further decreased by the subsequent addition of 10 μM CCh. Each point indicates the mean ± SE of pHi in 16 regions of the duct. b The pHi averages for 1 min just before (control) and 9–10 min after DMA addition (DMA), and 4–5 min after the subsequent addition of CCh (DMA + CCh). Data shown are mean ± SE (n = 7). c A representative trace of pHi change during the applications of DMA + DPC (200 μM) and DMA + DPC + CCh. Each point indicates the mean ± SE of pHi in 17 regions of the duct. d The pHi averages for 1 min just before (control) and 9–10 min after (DMA + DPC) the addition of DMA + DPC, and 4–5 min after the subsequent CCh addition (DMA + DPC + CCh). Data shown are mean ± SE (n = 6). e A time course of pHi change during the applications of DMA + 1 mM methazolamide (DMA + Met) and DMA + Met + CCh. Each point indicates the mean ± SE of pHi in 18 regions of the duct. f The pHi averages for 1 min just before (control) and 9–10 min after (DMA + Met) the addition of DMA + methazolamide, and 4–5 min after the subsequent CCh addition (DMA + Met + CCh). Data shown are mean ± SE (n = 5). g The maximal rates of CCh-induced decreases in pHi (−ΔpH per 10 s) in the presence of DMA. Simultaneous addition of either DPC or methazolamide with DMA reduced the rate. ***P < 0.001 in the unpaired Student’s t test. Data shown are mean ± SE (n = 7, 6, and 5, respectively)