Caspase-3 activity in hippocampal slices reflects changes in synaptic plasticity

Abstract

Electrophysiological measures of the functional activity of neurons in field CA1 in conditions of paired-pulse stimulation of Schäffer collaterals were performed in relation to the involvement of caspase-3 in mediating neuroplasticity; the relationship between functional activity and caspase-3 activity in hippocampal slices from Wistar rats was addressed. Enzyme activity was assessed in each individual slice at the end of the electrophysiological experiment. The results obtained here showed that the highest level of enzyme activity was seen when the efficiency of interneuronal interactions decreased. Nerve cell excitability showed no changes; interactions increasing synaptic efficiency, particularly in paired-pulse stimulation, produced normal response amplitudes. Further deterioration of the functional state of slices and impairments in spike generation were accompanied by increases in caspase-3 activity to the normal level. Increases in the activity of another proteinase, cathepsin B, were generally seen in any deviation from normal functioning, though there was no correlation with any of the electrophysiological parameters. It is suggested that high caspase-3 activity in slices is linked with neuroplastic processes in synapses and has no direct relationship to nerve cell apoptosis.

Histone H1 Poly[ADP]-Ribosylation Regulates the Chromatin Alterations Required for Learning Consolidation

“…Indeed, in mice lacking several of the genes that encode histone H1, there are alterations in chromatin structure and gene expression (Fan et al, 2005). Although the mechanism underlying the decrease in histone H1 expression remains unknown, we speculate that histone H1 may be a target for caspases and/or the proteasome when activated after neuronal synaptic activity (Patrick, 2006;Kudryashova et al, 2009). Our results confirm that, under physiological conditions, memory formation induces chromatin alterations through histone H1 release from certain RNA polymerase II-specific, CREB-and NF-B-dependent promoters.…”

Age-Related Intraneuronal Elevation of αII-Spectrin Breakdown Product SBDP120 in Rodent Forebrain Accelerates in 3×Tg-AD Mice

“…In the present study we did not detect a significant amount of nuclear labeling of active caspase-3 in the cortex or olfactory bulb. It should be noted that pharmacological studies indicate that caspase-3 activation is involved in many physiological cellular events under normal conditions, including modulation of long-term potentiation and other forms of synaptic plasticity, which are not associated with an overt presence of active caspase-3 fragments [48],[49],[50]. In addition, a degree of nuclear labeling of active caspase-3 can be seen in apparently healthy neurons in some brain regions [41],[48],[49],[51].…”

Cayman Ataxia-Related Protein is a Presynapse-Specific Caspase-3 Substrate

“…Recently, it has become evident that caspase may also play a critical role in signaling cascades [1][2][3]. For example, caspase activity is essential for learning and memory [4][5][6], neural stem cell differentiation [7], dendritic [8] and axon [9] pruning, sperm differentiation [10], and cell migration [11,12]. These nonapoptotic caspase functions may require local activation to prevent cell death, such as the case at the synapse.…”