Treatment with NO donor prevents the negative effect of isoflurane (ISO) and PDZ2WT peptide on hippocampal long-term potentiation. (A) Robust long-term potentiation was induced by high-frequency stimulation (HFS) in all groups. In the upper left quadrants, example traces of wild-type (WT) control (CON) + NO–treated and WT isoflurane + NO–treated (top), PDZ2MUT + NO–treated and PDZ2WT + NO–treated (bottom) groups before high-frequency stimulation (solid line trace) and 55 to 60 min after high-frequency stimulation (dashed line trace) are shown. (B) The median of normalized field excitatory postsynaptic potential (fEPSP) 55 to 60 min after high-frequency stimulation no longer shows a significant difference between WT CON and WT isoflurane when NO donor is added (WT CON + NO (n = 5) versus isoflurane + NO (n = 8), P = 0.284) or between PDZ2MUT and PDZ2WT (PDZ2MUT + NO (n = 5) versus PDZ2WT + NO (n = 6), P = 0.662). The data were analyzed with Mann–Whitney tests. Data from individual animals are plotted and color-coded by sex (red, female; blue, male). The data were plotted as median and interquartile (IQ) range. Values were considered significant at *P < 0.05 or less. Scale bar indicates 10 ms, 0.25 mV.