Figure 4.

Reactive hypertrophic astrocytes and electrophysiological neuronal alterations induced by the RK protocol. (A) (Left) Astrocytes identified as SR101 positives cells in stratum radiatum (SR) of the hippocampus showed a higher mean area in kindled animals (right, bars) indicating hypertrophic morphology. (B) Immunohistochemical staining of the hippocampus for GFAP (green), a specific marker of astroglial processes; and Hoecht (blue), a nuclear marker. Kindled rats showed an increased GFAP immunoreactivity throughout the hippocampus compared to control rats (388% in SR, and 205% in SO). Noticeably, similar levels of Hoechst in both experimental conditions were found (78% in SR and 88% in SO; n = 8 slices in RK and control). (C) (Left) Representative voltage membrane responses from control and kindled CA1 pyramidal neurons, evoked by the injection of hyperpolarizing and depolarizing current pulses (±0.5 nA; 750 ms), recorded at −65 mV imposed membrane potential. (Right) Mean frequencies and inter-spike interval (ISI) of AP discharges evoked by pulses of +0.5 nA (Mann Whitney test, * p < 0.05; n = 5 in RK and n = 3 in control; calibration bars: 100 μm, for all images).