Regulation of cathepsin B and caspase-3 in long-term plasticity

It has been previously shown that high-frequency stimulation of Schaffer collaterals (HFS), which induces LTP in the CA1 area of rat hippocampus, under normal conditions results in the activation of caspase-3. In contrast to caspase-3, the activity of cathepsin B weakly decreased in hippocampal slices subjected to HFS (the significance level was p = 0.07). This effect was observed in all slices frozen for subsequent measurements of enzymatic activity in 15 minutes and 3 hours after LTP induction under normal conditions and in the presence of caspase-3 inhibitors. The reciprocal influence of HFS, which was observed in the control slices depending on their initial state ( r = 0.59, p < 0.001 in control and r = 0.16, p = 0.46 in slices subjected to HFS), complicated simultaneous measurements of the activity of these enzymes. Though the effect of HFS on cathepsin B activity is not prominent, a significant difference in LTP magnitude in slices with low and high cathepsin B activity.