Pressure-volume curves in isolated atelectatic rat lungs after aluminum oxide microparticle inhalation.

Volume-pressure curves obtained from isolated atelectatic rat lungs under normal control conditions were compared with those obtained from lungs of animals previously exposed to inhalation of submicronic aluminum oxide particles for various periods of time. A dilating effect was recorded in rat lungs after aluminum oxide particle inhalation contrasting with the constricting effect reported by many authors in guinea pig, dog, cat, and man. Inhalation of fine aluminum particles before or after inhalation of sym athomimetic aerosol resulted in a more intense dilatation. The constricting eiect of carbachol was antagonized by prior inhalation of fine aluminum oxide dust and enhanced when the order of inhalations was reversed.