Fig. 5
Effects of blocking H+ generation by methazolamide, Ca2+ chelation and calmodulin inhibition on 10 μM carbachol (CCh)-induced pHi changes. a A time course of CCh-induced pHi change in the presence of 1 mM methazolamide (Met). CCh evoked an increase in pHi in all the ducts tested in the presence of methazolamide. Each point indicates the mean ± SE of pHi in 20 regions of the duct. b The pHi averaged for 1 min just before (control) and 4–5 min after (Met) the addition of 1 mM methazolamide and 4–5 min after 10 μM CCh addition (Met + CCh). The pHi was increased clearly by CCh in the presence of methazolamide. Data shown are mean ± SE (n = 5). c A representative trace of CCh-induced pHi change in the absence of the external Ca2+ (Ca free) and the presence of 1 mM methazolamide (Met) in the duct loaded with the Ca2+-chelating agent, BAPTA (50 μM BAPTA-AM for 15 min at 37 °C). Each point indicates the mean ± SE of pHi in 18 regions of the duct. d Loading BAPTA into the ducts and external Ca2+ removal significantly reduced the CCh-induced increase in pHi, comparing the data shown in b (Met + CCh) and d (Ca free + Met + CCh) (P < 0.05 in the unpaired Student’s t test, n = 5 and 7). The data in d are shown as mean ± SE. e A time course of CCh-induced pHi change in the presence of the calmodulin inhibitor, W-7 (W7, 100 μM). Each point indicates the mean ± SE in 24 regions of the ducts. f W-7 suppressed the CCh-induced increase in pHi in the presence of 1 mM methazolamide (Met). Data shown are mean ± SE (n = 5)