Evidence against a role of gap junctions in vestibular compensation
| Autor: | Nicolas Vibert, C. de Waele, E. Idoux, Pierre-Paul Vidal, A. Uno, Mathieu Beraneck, Isabelle Vassias |
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| Přispěvatelé: | Centre de Recherches sur la Cognition et l'Apprentissage (CeRCA), Université de Poitiers-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de Tours-Université de Poitiers |
| Jazyk: | angličtina |
| Rok vydání: | 2009 |
| Předmět: |
Male
Medial vestibular nucleus Anti-Inflammatory Agents Carbenoxolone Action Potentials Connexin Biology Cell junction Functional Laterality gap junction 03 medical and health sciences 0302 clinical medicine Vestibular nuclei otorhinolaryngologic diseases medicine Animals Premovement neuronal activity Rats Long-Evans ComputingMilieux_MISCELLANEOUS 030304 developmental biology vestibular compensation Neurons Vestibular system 0303 health sciences General Neuroscience Gap junction Gap Junctions in vitro Vestibular Nuclei Anti-Ulcer Agents Rats Connexin 43 [SCCO.PSYC]Cognitive science/Psychology Glycyrrhetinic Acid Vestibule Labyrinth Microtubule-Associated Proteins Neuroscience 030217 neurology & neurosurgery medicine.drug |
| Zdroj: | Neuroscience Letters Neuroscience Letters, Elsevier, 2009, 450, pp.97-101. ⟨10.1016/j.neulet.2008.11.062⟩ |
| ISSN: | 0304-3940 |
| Popis: | Vestibular compensation following unilateral labyrinthectomy is associated with modifications of the membrane and firing properties of central vestibular neurons. To determine whether gap junctions could be involved in this process, immunofluorescent detection of neuronal connexin 36 and astrocytic connexin 43 was performed in the medial vestibular nucleus (MVN) of rats. In non-lesioned animals, strong staining was observed with anti-connexin 43 antibodies, while moderate staining was obtained with the anti-connexin 36 antibody. However, the expression of either type of connexin was not modified following unilateral labyrinthectomy. These morphological observations were complemented by pharmacological tests performed during extracellular recordings of MVN neurons in guinea pig brainstem slices. In non-lesioned animals, the gap junction blocker carbenoxolone reversibly decreased or suppressed the spontaneous discharge of about 60% of MVN neurons. This reduction was often associated with a long-duration disruption of the regularity of spike discharge. Both effects were mimicked by several other gap junction blockers, but not by glycyrrhizic acid, an analog of carbenoxolone that does not block gap junctions but reproduces its non-specific effects, nor by the selective inhibitor of astrocytic connexin-based networks endothelin-1. Similar effects of carbenoxolone were obtained on the spontaneous activity of ipsilesional MVN neurons recorded in brainstem slices taken from labyrinthectomized animals. Altogether, these results suggest that neuronal gap junctions are involved in shaping the spontaneous activity of MVN neurons. However, unilateral labyrinthectomy does not affect the expression of gap junctions in vestibular nuclei nor their implication in the regulation of neuronal activity. |
| Databáze: | OpenAIRE |
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