Transport of α-Aminoisobutyric Acid by Alveolar Macrophages Incubated With Cigarette Smoke and Nicotine

Abstract

Aqueous extracts of cigarette smoke or nicotine at concentrations that did not greatly affect cellular viability, as measured by dye exclusion, markedly reduced the transport of α-aminoisobutyric acid (AIB) by rabbit alveolar macrophages.

Smoke extract was prepared by drawing smoke from three cigarettes (100 mm, nonfilter) into 25 ml of a modified Hanks solution. Aqueous extract of smoke, and nicotine, produced a biphasic effect on AIB transport: a stimulation at low concentrations and an inhibition at higher concentrations. Cell viability, as estimated by dye exclusion, was reduced only 17% by the highest concentration of the smoke extract.

These data suggest that transport of a nonmetabolizable amino acid, ¹⁴C-AIB, is a sensitive and quantitiative assay for examining the influence of air contaminants on membrane permeability.