The neutrophil, friend or foe: pharmacologic manipulation.

We describe some features of neutrophil migration and their defense or injury mechanism in the lung. Employing an intratracheal silica instillation model in rats, we examined the effects on the silica-induced neutrophil migration of mepacrine, colchicine and reserpine on such migration in vivo and of mepacrine on phorbol-stimulated elastase release and superoxide anion generation by human neutrophils in vitro. Mepacrine sharply diminished neutrophil migration, O2 and elastase release. Colchicine produced variable effects on neutrophil migration which was unaffected by the mast cell agent reserpine. The implications for lung injury and therapy are discussed.