In these experiments, granule cells were examined under current clamp and voltage clamp, before and after addition of TEA. Under current clamp, we measured AP width in 1.5 mM [Ca2+]o at 0 mV, without (pink) or with (brown) 1 mM TEA. Likewise we measured AP width in 3 mM [Ca2+]o, without (yellow) or with (green) 1 mM TEA. Under voltage clamp, peak voltage-dependent Na+ and K+ currents were estimated by measuring the peak amplitudes of inward and outward current responses to depolarizing voltage pulses to 0 mV. Group results show significant increases in AP width with TEA, both in 1.5 mM [Ca2+]o and in 3 mM [Ca2+]o. Peak K+ currents are decreased in the presence of TEA, both in 1.5 mM [Ca2+]o and in 3 mM [Ca2+]o, while peak Na+ currents are not significantly changed. Levels of significance for statistical tests (paired t-test): **, p<0.01; ***, p<0.001.