MeHg-induced potentiation of IGABA in oocytes expression α1β2γ2S receptors is time-dependent and reversible. Top: whole cell currents were recorded before, at 30 min after MeHg exposure, and following a 10 minute wash respectively. Bottom: Time-course of MeHg-induced potentiation of GABA currents mediated by α1β2γ2S receptors. Application of 5 μM MeHg began at 0 min, continued for 30 min, was subsequently stopped, and the oocyte washed with MeHg-free solution. Values are mean ± SEM (n = 7).