The effect of opioid agonists of delta-class DSLET, mu-class DAMGO, kappa-class U-69593 and an opioid antagonist, naloxone, on MTT activity of NALM-1 leukemic cells.

The effects of synthetic agonists of delta-, mu-, kappa-opioid classes were studied on the proliferation of NALM-1 leukemic cells, using the MTT-test. Delta-opioid DSLET and mu-opioid DAMGO mildly and transiently decreased, in higher concentrations, the MTT-activity of NALM-1 cells after 6 h of treatment. The kappa-opioid agonist U-69593 mildly suppressed proliferation of NALM-1 cells after 48 h of treatment. Naloxone, an opioid receptor antagonist, mildly and transiently diminished MTT-activity of NALM-1 cells after 6 h of treatment. Treatment with opioid agonists, DAMGO, DSLET, U-69593, and an opioid antagonist naloxone for 6, 24, and 48 h, did not trigger DNA fragmentation, which was considered as a possible mechanism of action.