[P2.70]: Sub‐field location in hippocampal slices of cofilin‐actin rods induced by amyloid‐β and other stimuli

days 4 (P4)-P14 or P1-7. In P4-14 hippocampi, a reversed effect of GVG on GABA synthesizing enzyme, GAD65/67, was observed by means of immunoblot analysis; a short-term (2 weeks) decrease and longterm (16 weeks) increase in GAD65 and GAD67 levels (50% and 150% of Ct, respectively, P < 0.05). In young P4-14 and P1-7 cortex GAD65/67 levels were reduced by 50% (P < 0.01), however the long-term influences on GAD65/67 were abolished. Analysis of the Ca binding proteins parvalbumin (PV) and calbindin (CB) in the hippocampus showed region-specific effects on PV-IR cells, and no influence on the number and size of CB-IR cells, though CB levels were elevated in young and adult GVG mice. The K-Cl cotransporter KCC2 was elevated in hippocampi of P4-14 GVGtreated mice aged 2 and 16 weeks (148% and 165% of Ct, respectively, P < 0.05). In the cortex of both treatment periods long-term elevations were observed, whereas no short-term effects were detected between GVG and Ct. The KCC2 oligomer/ monomer ratio on the plasma membrane enriched fraction in the hippocampus, shows an age-dependent outcome; a short-term increase was followed by a long-term decrease in GVG compared to Ct (145% and 70% of Ct, respectively, P < 0.05). No changes were observed in the KCC2 oligomer/monomer ratio in the plasma membrane in P4-14 cortex. We conclude that, mainly in the hippocampus, the GABAergic system in the newborn is highly susceptible to GABA enhancement, with long-term consequences on the potency of the inhibitory system.