Effects of individual stressors used in a battery of "chronic unpredictable stress" on long-term plasticity in the hippocampus of juvenile rats.

We have studied alterations in the properties of long-term potentiation (LTP) in hippocampal slices of juvenile rats induced by the exposure of animals to different individual stressors usually used in batteries of chronic unpredictable stress (CUS), a widely used model of depression. Social isolation for 16 h did substantially affect neither the magnitude and nor the development of LTP. The effects of stroboscopic illumination and water deprivation appeared most severe, though opposite: the first stressor had activating effect, whereas the second one inhibited the development of LTP.

Caspase activity is essential for long-term potentiation.

Slices from rat hippocampus were incubated with the caspase-3 inhibitor N-benzyloxycarbonyl-Asp-Glu-Val-Asp fluoromethylketone (Z-DEVD-FMK) or with the inactive peptide N-benzyloxycarbonyl-Phe-Ala fluoromethylketone (Z-Phe-Ala-FMK) for 30 min. The peptides changed neither input-output curves nor paired-pulse effects at 70-msec interpulse intervals, nor amplitudes of pop spikes in the CA1 region 1.0-6.

Footshock stress alters early postnatal development of electrophysiological responses and caspase-3 activity in rat hippocampus.

Postnatal changes in population spike (PS) amplitudes and caspase-3 activity were compared in the hippocampi of control rats and experimental animals subjected to a brief footshock on postnatal day (PD) 13. Footshock induced an increase in maximal PS amplitudes during the early period (from PD 14 to PD 16), however, the difference between stressed and control animals gradually decreased with age up to PD 21. No difference between hippocampal caspase-3 activity in control and footshock groups was revealed within the PD 14-17.