Age-related modification on the effects of thiopental in rat hippocampal CA1

We compared age-related alterations in the electrophysio logical properties of CA1 hippocampal pyramidal neurons at 4 weeks (younger) and 18 weeks (elder) of age, using rat in vitro slice preparation. Method. Transverse hippocampal slices (400 μm) were prepared from male Wistar rats. Two sets of bipolar electrodes were placed on Schaffer collateral fibers to elicit population spikes (PS) in area CA1 [Sch] and on alveus hippocampi to activate the inhibitory interneurons for GABAergic modulation →Alv]. Results. In younger and elder groups, thiopental depressed PS →Sch + Alv]/PS [Sch] to 69%and 84%, respectively. In elder group, duration of the effects of thiopental (PS →Sch + Alv]/PS →Sch] <1) was shorter (116 ms) than that of younger group (375 ms). Conclusion. We demonstrated the age-dependent decrease of the GABAergic inhibition in rat CNS preparations in vitro.