Blocking Action of Compounds 12 and 13 on MDMAInduced Release. If added 4 min before MDMA to the superfusion buffer, 12 and 13 concentration-dependently suppressed the release induced by 3 M MDMA in NET-, SERT-, and DAT-expressing cells (Figs. 7 and 8). Compound 12 (100 M) suppressed MDMA-induced release mediated by the DAT to levels slightly beneath basal efflux (Figs. 7C and 8C). The potency of 13 in its inhibitory action on MDMAinduced release was in agreement with its potency in uptake inhibition experiments: 13 suppressed MDMA-induced release mediated by the SERT more potently than NET-mediated release, whereas MDMA-induced release mediated by the DAT was only weakly inhibited in concentrations up to 100 M (Fig. 8C)