Characterization of SLEs in hippocampal entorhinal cortex slices from wild-type and nNOS^−/− mice. A, Representative traces depicting SLE-associated changes in field potential and [K⁺]_o in slices from wild-type (top 2 traces) and nNOS^−/− (bottom 4 traces) mice. SLEs of similar lengths and amplitudes recurred regularly in slices from wild-type mice. In contrast, SLE interval and the amplitude of the accompanied changes in [K⁺]_o were more variable in slices from nNOS^−/− mice. The SD of the SLE interval was significantly higher in slices from nNOS^−/− mice compared with wild type. Arrows mark transition from recurrent SLEs to clonic discharges and vice versa. B, Characteristics of typical SLEs in slices from wild-type (top traces) and nNOS^−/− (bottom traces) mice at a shorter timescale. Note the presence of intermittent SLEs lacking of the DC shift between regular SLEs in the example trace from nNOS^−/− mice. Representative traces depicting SLE-associated changes in field potential and [K⁺]_o in a slice from nNOS^−/− mice in the presence of 7-NI and PTIO. Note that SLE characteristics in NO-deprived slices were similar to the SLEs in slices without 7-NI and PTIO, indicating that SLE initiation is independent on NO in nNOS^−/− mice. fp, Field potential.