Following incubation with [14C]gamma-aminobutyric acid (GABA) or [3H]dopamine, slices of rat striatum were superfused with media containing 36 mM K+ or ethylenediamine (EDA), 1 or 5 mM. Both K+ and EDA induced a release being largely Ca2+-dependent, while the EDA-induced release was not. Whereas K+ also evoked a Ca2+-dependent release of [3H]dopamine, EDA evoked no release of dopamine. EDA may therefore have potential as a specific GABA releasing agent.