MECHANISM OF DRUG-INDUCED VACUOLIZATION IN TISSUE CULTURE.

Abstract Procaine, procaine amide, cocaine, pilocarpine, ephedrine, and atropine all produced marked cytoplasmic vacuolization in cells cultured in vitro . The accumulation of vacuoles did not seem to affect either the motility or mitosis of the cells. After the drug was removed by washing, vacuoles eventually disappeared completely. Ammonium chloride produced essentially the same phenomenon as the drugs. The process of vacuolization induced by the compounds tested was influenced by the pH of the external medium; in media adjusted to an acid pH where the undissociated base was in relatively low concentration, vacuolization was reduced. It was postulated that penetration of weak bases was the factor responsible for vacuole formation which in turn might be a means of counteracting cellular pH changes.