Neurotoxic effects of methamphetamine assessed in three-dimensional reaggregate tissue cultures

Three-dimensional, rotation-mediated, reaggregate tissue cultures formed from dissociated fetal rostral mesencephalic tegmental (RMT) and corpus striatal (CS) or frontal cortical (FCx) cells were used to study methamphetamine neurotoxicity. Analysis of dopamine (DA), serotonin (5-HT) and gamma-aminobutyric acid (GABA) levels using HPLC techniques revealed decreases in RMT-CS and RMT-FCx reaggregate DA and 5-HT levels after treatment between 14 and 21 days in culture with methamphetamine in concentrations ranging from 10(-6)M to 10(-3)M. Dopamine cell numbers in RMT-CS and RMT-FCx reaggregates were estimated after visualization by histofluorescent techniques. Methamphetamine treatment caused decreases in DA cell numbers which paralleled the decreases in endogenous DA levels. Estimates of the accumulation of exogenous DA by RMT-CS reaggregates treated with methamphetamine showed that the amount of accumulation per cell remained fairly constant despite marked reductions in total DA cell numbers. This suggests that the reductions in endogenous DA levels following methamphetamine were secondary to loss of entire DA neurons rather than of a portion of the terminal axonal fields in the surviving neurons. Reaggregate tissue cultures are a useful tool in the study of potential neurotoxic effects of new or untested psychotherapeutic agents.