Electrochemical study of oxygen behaviour with lung surfactant.
At the very beginning of its way to any tissue oxygen has to cross the lung surfactant surface layer LSSL. The influence of LSSL on oxygen was studied in vitro at model interfaces using sensitive d.c. electrochemical techniques. LSSL adsorbed from lung washings at the dropping mercury electrode/saline interface shifted the half-wave potential of oxygen reduction E1/2 towards more negative values. The magnitude of delta E1/2 was dependent on the lung washing concentration and showed a saturation tendency. The intensity of the reduction current was higher in saline samples with surfactant than without and had a rather rising tendency. Lipids extracted from lung washings or amniotic fluid being spread as a condensed multilayer at the saline/air interface and re-adsorbed on a hanging mercury electrode surface produced a several time bigger shift of oxygen reduction E1/2 towards negative potential values than the lung washings did. The surfactant specific 34 kD protein and lung washing proteins injected beneath the lipid layer produced a positive potential shift. Dust-treatment-caused changes in surfactant quality/quantity resulted in bigger delta E1/2 values. The data suggest that the LSSL represents a certain energetic barrier or even an one-way gate to the crossing oxygen the efficiency of which depends on the composition/structure of the LSSL and that the aqueous hypophase under the LSSL in the alveoli is a place of storage for the oxygen.
Ladanyi
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Department of Occupational Health, University of Goettingen, Federal Republic of Germany.
D000818:Animals; D004391:Dust; D004553:Electric Conductivity; D004563:Electrochemistry / Q000379:methods; D007700:Kinetics; D008564:Membrane Potentials; D010084:Oxidation-Reduction; D010100:Oxygen; D011663:Pulmonary Surfactants / Q000502:physiology
D004391:Dust; D011663:Pulmonary Surfactants; D010100:Oxygen