STATIC VOLUME–PRESSURE RELATIONS IN GUINEA PIG LUNGS AFTER INHALATION OF ALUMINUM OR IRON OXIDE PARTICLES AND BRONCHODILATOR AEROSOLS

Volume–pressure curves obtained from isolated atelectatic guinea pig lungs under normal controlled conditions are compared with those obtained from animals having inhaled fine aluminum or iron oxide particles. After particles inhalation, the inflation curves are deviated to the right, showing a constricting effect. Previous exposure to low concentration of isoproterenol aerosol fails to reverse completely the constricting effect induced by a prior inhalation of aluminum oxide particles although in combination with diphenhydramine or at a higher concentration an antagonistic action appears. Cyproheptadine aerosolation also prevents the constricting effect of inhaled aluminum oxide particles The constricting effect of iron oxide was not prevented by those dilating aerosols at concentrations used.