The calcineurin inhibitor Ascomicin interferes with the early stage of the epileptogenic process induced by Latrunculin A microperfusion in rat hippocampus.

Abstract

Latrunculin A microperfusion in rat hippocampus has shown to be an effective model of acute and chronic seizures for neurochemical studies. The intervention over early synaptic plasticity changes after the epileptogenesis onset represents a big challenge on the design of a suitable therapy to impair the epilepsy development. We previously suggested that receptor location might be essential for controlling neuronal excitability, and that disruption of local cytoskeletal dynamics followed by drastic changes in the synaptic/extrasynaptic ratio of NMDA, AMPA receptors and their subsequent downstream signalling may play an important role in the pathogenesis of seizures. In the present study, we performed a pharmacological intervention in the Latrunculin model by using Ascomicin (ASC) and Phenytoin (PHT). We pointed out the inhibitory action of ASC over the protein phosphatase 2B (PP2B). PP2B pathological mechanism involves changes in actin cytoskeleton and showed to avoid those subsequent changes previously observed in PSD components. On the contrary, PHT didn't seem to modify the F-actin depolymerization process induced, showing a similar redistribution pattern from the PSD towards the extrasynaptic site of several molecular components with more or less dependence on actin for their location, including glutamate receptors. Overall, we propose that the early intervention over changes on the synapse during the epileptogenic process might represent the best approach to avoid the onset of chronic refractory seizures our model. On this regard, the therapeutic potential of ASC, FK506 and derivatives should be further explored as a possible tool in the intervention over epilepsy and other brain diseases.