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. 2012 Jun;166(4):1388–1402. doi: 10.1111/j.1476-5381.2012.01883.x

Figure 4.

Figure 4

Effect of the ion channel modulators amiloride, BaCl2 NFA and NPPB on the ACh effect in mouse tracheal epithelium. (A) Upon application of 10 µM amiloride (luminal), the ISC decreased. When ACh (100 µM, luminal) was added as well, the typical ACh effect consistent of a transient peak followed by a lower plateau was visible. (B) The ACh-induced current (IACh) in presence of amiloride (n= 6) was not significantly different from the control effect (n= 7) (peak: P= 0.20, plateau: P= 0.11). (C) A typical trace for the effect of ACh (100 µM, luminal) before and after basolateral perfusion of 5 mM BaCl2. Application of ACh on the luminal side of the epithelium in the presence of BaCl2 on the basolateral side, led to a current increase. (D) The ACh effect was significantly decreased in the presence of basolateral BaCl2, the peak as well as the plateau component (n= 6, P < 0.05). (E) The current trace shows the effect of the application of 100 µM ACh on the luminal side of the epithelium, both under control conditions and in the presence of NFA (100 µM, luminal). Perfusion with NFA led to a current decrease. The tissue was pre-incubated for approximately 8 min with NFA before ACh application. (F) Both components of the ACh effect in the presence of NFA (n= 6) were significantly reduced (P < 0.05) compared with the control ACh effect (n= 7). Similarly, the ACh mediated peak current was significantly reduced in the presence of the chloride channel inhibitor NPPB (100 µM, luminal) compared with control conditions (n= 7, P < 0.05) and the plateau current was abolished (n= 7, P < 0.05). (G) Application of ACh (100 µM, luminal) led to the typical biphasic increase of the ISC. In the presence of NFA (100 µM, luminal) and BaCl2 (5 mM, basolateral), additional application of ACh had no effect. The tissue was pre-incubated with NFA for 12 min and with BaCl2 for 6 min before the ACh application, resulting in a time gap of 20 min between the first and the second ACh application, including the washing time. (H) The presence of luminal NFA and basolateral BaCl2 had no significant effect on the ACh-induced current (n= 4, P= 0.39).