Effects of addicting and nonaddicting drugs on HeLa cells

After 70 subcultivations of HeLa cells in the presence of amphetamine, diphenhydramine hydrochloride, caffeine, codeine, or morphine, cells were obtained with increased tolerance to the respective drug. Withdrawal of amphetamine, diphenyhydramine hydrochloride or morphine from cells cultivated 645 days in the presence of the drug yielded cells that had either a decreased growth rate in the absence of drug or superior plating efficiencies with low drug concentration when compared to untreated HeLa cells. These observations would be expected from addicted cells. Cinematographic observations showed cell membrane undulation decreased in the presence of morphine. The membrane undulations of cells tolerant to morphine were less sensitive to that drug.