title: Alveolar subphase pH in the lungs of anesthetized rabbits.
abstract: We measured the pH of the alveolar subphase fluid by puncturing the most superficial alveoli of the exposed lungs of anesthetized rabbits with H+-selective and nonselective KCl microelectrodes. In these experiments, we bathed the lung surface with paraffin oil or buffered Ringer's solutions that had a CO2 tension of 40 Torr (1 Torr = 133.3 Pa) and found an alveolar pH of 6.92 +/- 0.01 (mean +/- sEM). When the pH of the surface buffer was below 6.7 or above 7.5, alveolar pH varied with surface buffer pH. With the nonselective electrode, we did not find a significant electrical potential difference between the alveolar fluid and the pleural surface. These results are consistent with active transport of H+ (or HCO3(-) across alveolar epithelium.
mesh_terms: D000768:Anesthesia, General; D000818:Animals; D006863:Hydrogen-Ion Concentration; D008168:Lung / Q000502:physiology*; D008722:Methods; D008839:Microelectrodes; D011199:Potentiometry; D011650:Pulmonary Alveoli / Q000502:physiology*; D011817:Rabbits