Figure 2. The paracellular pathway of human airway epithelia is HCO₃ ⁻ permeable.

n ≥ 6 donors for all panels and all error bars represent standard deviations of the mean. A, paracellular P_Na/Cl vs. P_Na/HCO3, each circle represents a single human donor; P = 0.91; two‐tailed paired Student's t test; n = 12 donors. B, paracellular P_Na/HCO3 ± 1 mm acetazolamide, each circle is one donor; P = 0.45; two‐tailed paired Student's t test; n = 6 donors. C, relative paracellular permeabilities, P_ion/P_Na, for several cations and anions. We cannot reject the null hypothesis that the slopes were zero; cations P = 0.15, anions P = 0.76; F test; n values are shown in figure.