Figure 5: Apical ATP is not required for carbachol-induced inhibition of Isc.
From: Inhibition of airway surface fluid absorption by cholinergic stimulation
(A) Inhibition of Isc across sheep trachea by 100 μM apical ATP before (top trace) and after (bottom trace) 100 μM basolateral carbachol. Inhibition of Isc by ATP is much smaller after carbachol treatment. Benzamil (10 μM) was applied apically. (B) Summary of ATP results in sheep airways (n = 3); *,**significantly different from control, “after,” P < 0.05 and P < 0.005, respectively. (C) In sheep trachea, apyrase pretreatment (10 U/ml, apical) had no effect on carbachol induced inhibition of ENaC-dependent Isc. (D) By contrast, in sheep trachea apyrase (top trace) abolished ATP induced inhibition of ENaC-dependent Isc (shown without apyrase in bottom trace). Representative traces, n = 6 experiments from 4 sheep.
