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Fig. 1 | The Journal of Physiological Sciences

Fig. 1

From: Different rate-limiting activities of intracellular pH regulators for HCO3 secretion stimulated by forskolin and carbachol in rat parotid intralobular ducts

Fig. 1

Forskolin + IBMX-induced decrease in the pHi. a Time courses of the pHi changes in rat parotid intralobular ducts by the addition of 10 μM forskolin + 100 μM IBMX (F+I). Each point indicates the mean ± SE of pHi in 19–28 regions of the ducts. The pHi level was reduced by the addition of F+I in all the ducts tested. b Relationships between the F+I-induced pHi changes averaged during 4–5 min after F+I addition (ΔpH) and the resting pHi levels averaged for 1 min just before F+I addition. Each point was obtained from the data in a (n = 9). c The pHi averaged for 1 min just before F+I addition (control) and 4–5 min after F+I application (F+I). Data shown are mean ± SE calculated from the traces in a (n = 9). d A time course of pHi change in the duct by F+I addition of under the inhibition of carbonic anhydrases by 1 mM methazolamide (Met). Each point indicates the mean ± SE of pHi in 20 regions of the duct. e The effect of 1 mM methazolamide on the F+I-induced pHi change. The pHi averages for 1 min just before (control, pHi; 7.57–7.83) and 4–5 min after (Met) the addition of methazolamide, and 4–5 min after the subsequent addition of F+I (Met + F+I) are denoted. Data shown are mean ± SE (n = 10). f A time course of pHi change in the duct by F+I addition under the blocking of CFTR Cl channels by 10 μM CFTR inhibitor 172 (CFTR172). Each point indicates the mean ± SE of pHi in 17 regions of the duct. g The pHi averages for 1 min just before (control, pHi; 7.39–7.91) and 4–5 min after the addition of the CFTR inhibitor (CFTR172), and 4–5 min after the subsequent addition of F+I (CFTR172 + F+I) are shown. Data shown are mean ± SE (n = 5). h Addition of 10 μM CFTR inhibitor 172 (CFTR172) almost completely blocked the inward current induced by 10 μM forskolin + 100 μM IBMX (F+I). The current was measured by using the gramicidin-perforated patch techniques in a single ductal cell. Small and brief voltage pulses (5 mV, 0.2 s) were superimposed on the holding potential (−80 mV) in every 10 s. The broken line indicates the zero level of the current. Similar results were obtained in the other 4 experiments

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