Louis, MO), was made up to four different concentrations (0.1, 1, 10, and 100 μmol/L) in aCSF and kept frozen until use. The solutions were delivered through an electrical syringe pump (Instech, Plymouth Meeting, PA) calibrated to deliver a total volume of 1 μL over 12.5 min. The experiment consisted of a baseline recording (1 h) and an infusion period, after which evoked responses were recorded for an additional 3 h following termination of infusion. Histological Inhibitors,research,lifescience,medical assessment of placements, and data analysis Upon termination of recording, anesthetized animals were decapitated
and the brains were removed quickly and frozen for cryostat sectioning. Coronal sections (30 μm) were taken and electrode placements were visualized using cresyl violet staining and glycogen phosphorylase histochemistry, as described by Walling et al. (2007). Animals in which electrode or cannula Inhibitors,research,lifescience,medical placement occurred outside the dentate gyrus were excluded from analysis. DataWave software was used to measure the population spike amplitude (first positive peak − first valley) and fEPSP Inhibitors,research,lifescience,medical slope (ΔV/Δt) for each waveform recorded. The average value for the last 30 min of baseline recording
was used to see more evaluate changes in both population spike amplitude and fEPSP slope for the duration of recording. Measurements were normalized to the mean of the population spike amplitude or fEPSP slope measurement for the 30-min period prior to infusion onset and transformed into 5-min means. Within-group Inhibitors,research,lifescience,medical analyses Repeated measures analysis of variance (ANOVA) was used to evaluate the effects of intrahippocampal application of ISO on population spike amplitude and fEPSP slope at each of the concentrations (aCSF, 0.1, 1, 10, 100 μmol/L × time). If significant effects were found, further post hoc analyses were carried out using Fisher’s test for Least Significant Differences (LSD) to characterize the differences. Effects were considered significant
if the 5-min means after the start of the infusion were significant (P < 0.05) from Inhibitors,research,lifescience,medical all (6) 5-min means in the 30-min baseline period. A minimum of two consecutive mean calculations were required to be statistically different from baseline. Significance was set at P < 0.05. Between-group analyses Two-way repeated measures ANOVAs (groups: aCSF, 0.1, 1, 10, 100 μmol/L × times: 15 min preinfusion and 15, 110, and 180 min postinfusion) were used to assess below differences in the effects among varying concentrations of ISO. Again, LSD analysis was employed when the interaction was found to be significant and the criteria level was set at a minimum of P < 0.05. Correlations and input/output curves Pearson product–moment correlations were calculated across all animals in each group for the natural variations in slope–spike relationships at the same time points analyzed in the between-group tests (15 min preinfusion and 15, 110, and 180 min postinfusion). A two-tailed test of significance (P < 0.05) was employed.