title: Hippocampal Hyperexcitability is Modulated by Microtubule-Active Agent: Evidence from In Vivo and In Vitro Epilepsy Models in the Rat.
abstract: The involvement of microtubule dynamics on bioelectric activity of neurons and neurotransmission represents a fascinating target of research in the context of neural excitability. It has been reported that alteration of microtubule cytoskeleton can lead to profound modifications of neural functioning, with a putative impact on hyperexcitability phenomena. Altogether, in the present study we pointed at exploring the outcomes of modulating the degree of microtubule polymerization in two electrophysiological models of epileptiform activity in the rat hippocampus. To this aim, we used in vivo maximal dentate activation (MDA) and in vitro hippocampal epileptiform bursting activity (HEBA) paradigms to assess the effects of nocodazole (NOC) and paclitaxel (PAC), that respectively destabilize and stabilize microtubule structures. In particular, in the MDA paroxysmal discharge is electrically induced, whereas the HEBA is obtained by altering extracellular ionic concentrations. Our results provided evidence that NOC 10 μM was able to reduce the severity of MDA seizures, without inducing neurotoxicity as verified by the immunohistochemical assay. In some cases, paroxysmal discharge was completely blocked during the maximal effect of the drug. These data were also in agreement with the outcomes of in vitro HEBA, since NOC markedly decreased burst activity that was even silenced occasionally. In contrast, PAC at 10 μM did not exert a clear action in both paradigms. The present study, targeting cellular mechanisms not much considered so far, suggests the possibility that microtubule-active drugs could modulate brain hyperexcitability. This contributes to the hypothesis that cytoskeleton function may affect synaptic processes, relapsing on bioelectric aspects of epileptic activity.
authors.affiliation: Department of "Experimental Biomedicine and Clinical Neuroscience" (Bio.Ne.C.), "Sezione di Fisiologia Umana G. Pagano", University of Palermo Palermo, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Carletti
authors.affiliation: Department of "Experimental Biomedicine and Clinical Neuroscience" (Bio.Ne.C.), "Sezione di Fisiologia Umana G. Pagano", University of PalermoPalermo, Italy; Post-graduate School of Nutrition and Food Science, University of PalermoPalermo, Italy.
authors.forename: Pierangelo
authors.initials: P
authors.lastname: Sardo
authors.affiliation: Department of "Experimental Biomedicine and Clinical Neuroscience" (Bio.Ne.C.), "Sezione di Fisiologia Umana G. Pagano", University of Palermo Palermo, Italy.
authors.forename: Giuditta
authors.initials: G
authors.lastname: Gambino
authors.affiliation: Department of Neuroscience, The Scripps Research Institute Jupiter, FL, USA.
authors.forename: Xin-An
authors.initials: XA
authors.lastname: Liu
authors.affiliation: Department of "Experimental Biomedicine and Clinical Neuroscience" (Bio.Ne.C.), "Sezione di Fisiologia Umana G. Pagano", University of PalermoPalermo, Italy; Post-graduate School of Nutrition and Food Science, University of PalermoPalermo, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Ferraro
authors.affiliation: Department of "Experimental Biomedicine and Clinical Neuroscience" (Bio.Ne.C.), "Sezione di Fisiologia Umana G. Pagano", University of PalermoPalermo, Italy; Department of Neuroscience, The Scripps Research InstituteJupiter, FL, USA.
authors.forename: Valerio
authors.initials: V
authors.lastname: Rizzo
keywords: electrophysiology; epilepsy; hippocampus; maximal dentate activation; microtubule; nocodazole; paclitaxel