Acute transverse 300 μm hippocampal slices were prepared from P17–P21 mice. Cultured hippocampal slices were prepared from P6–P9 mice as previously described (Schnell et al., 2002). Paired recordings of eEPSC’s involved simultaneous whole-cell recordings at room temperature from one infected/transfected GFP-positive neuron and a neighboring GFP-negative neuron while stimulating Schaffer collaterals. Series resistance was monitored and not compensated, and cells in which series resistance was above 30 MΩ or varied by 25% during a recording session were discarded. mEPSCs were recorded in the presence of 0.5 μM TTX. mEPSCs with an amplitude of ≥ 5 pA and a rate of rise of ≥ 4 pA/ms were automatically detected and analyzed offline with customized software in (IGOR). Fast application of 1 mM glutamate to somatic and HEK cell outside-out patches for 1 and 100 ms by a piezoelectric controller (Siskiyou) was used to determine AMPAR deactivation and desensitization kinetics, respectively. Our open-tip response experiments show the 20%–80% exchange times to be less than 200 μs.
