EXTRACELLULAR ATP STIMULATES ELASTASE SECRETION FROM HUMAN NEUTROPHILS AND INCREASES LUNG RESISTANCE AND SECRETION FROM NORMAL RAT AIRWAYS AFTER INTRATRACHEAL INSTILLATION

The effect of ATP on intracellular Ca2+ levels and elastase secretion in isolated normal human peripheral blood neutrophils was investigated as was its in vivo effect on lung resistance and mucous secretion. ATP (10(-5) M) increased [Ca2+]i from 61 +/- 3 to 165 +/- 15 nM in nonactivated neutrophils; elastase secretion was increased by 40% from nonactivated neutrophils but was unaffected in fMLP (10(-5) M) activated cells. Instillation of ATP (10(-5) and 10(-3) M) into the airways of brown Norway rats increased both lung resistance and secretion. These findings suggest that aerosolization of ATP into the cystic fibrosis-affected bronchial tree might be hazardous in terms of enhancement of parenchymal damage, which would result from neutrophil elastase release. and in terms of impaired respiratory lung function.