Figure 4. Ca²⁺-permeable AMPA receptors are unlikely involved in mediating DAC miniature EPSCs (mEPSCs). α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA) receptor-mediated miniature excitatory postsynaptic currents (mEPSCs) were recorded from dopaminergic amacrine cells (DACs) in wild-type TH::RFP mice at the holding potential of −70 mV in the presence of 1 µM TTX and a cocktail of antagonists (see Figure 1). A: Representative sweeps recorded from a DAC before and during 5 µM PhTX are shown. B: Cumulative probability distributions of AMPA receptor-mediated mEPSC amplitudes from this cell show that PhTX had no effect (p>0.05, Mann–Whitney U test). C: A bar graph shows that average AMPA receptor-mediated mEPSC amplitudes were not changed by PhTX (mean ± standard error of the mean (SEM), n=6, p>0.05, paired t test).