Figure 2.

Effect of oral administration of ethanol on the induction of LTP at medial perforant path-granule cell synapses in the dentate gyrus of anaesthetized rats. (A) Time-course of changes in evoked potentials. Insets are representative records of evoked potentials at the times denoted by the numbers. The amplitude of population spike (PS) was defined as the average of a plus b, and the slope of pEPSP was measured on the rising phase (e). Saline or 1 g kg⁻¹ ethanol was orally administered at time −30 min, and tetanic stimulation (30 pulses at 60 Hz) was applied at time 0. In another group, 1 g kg⁻¹ ethanol was orally administered at time −30 min, but tetanic stimulation was not applied. The population spike amplitudes and the pEPSP slopes were expressed as the percentage of baseline values immediately before tetanic stimulation (time 0). (B) Dose-dependent effect of ethanol. Intact group received tetanic stimulation without oral administration. Saline or ethanol (0.5–2 g kg⁻¹) was orally administered 30 min prior to tetanic stimulation. The average of the population spike amplitudes 30–60 min after tetanic stimulation was calculated as an index of LTP magnitude. All data are the mean±s.e.mean of five rats. ^**P<0.01 vs saline group, Duncan's multiple range test.