TITLE

Analysis of connexin expression during seizures induced by 4-aminopyridine in the rat hippocampus

AUTHOR(S)
Laura, Medina-Ceja; Xóchitl, Flores-Ponce; Anne, Santerre; Alberto, Morales-Villagrán
PUB. DATE
August 2015
SOURCE
Journal of Biomedical Science;Aug2015, Vol. 22 Issue 1, p1
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Background: In epilepsy, seizures are generated by abnormal synchronous activity in neurons. In the rat hippocampus (HIP), epileptiform activity has been found to be associated with gap junctions (GJs). GJs are formed by the combination of two hemichannels, each composed of six connexins. At low doses, the convulsive drug 4-aminopyridine (4-AP) produces epileptiform activity without affecting glutamate levels; therefore, GJs could participate in its effect. Based on this argument, in this study, the expression of Cx 32, Cx 36 and Cx 43 protein and mRNA in the HIP of rats treated with 4-AP was evaluated. The evaluation of connexins was carried out by chemifluorescent immunoassay, semiquantitative RT-PCR and immunofluorescence to detect the amount and distribution of connexins and of cellular markers in the HIP and dentate gyrus (DG) of animals treated with NaCl and 4-AP in the right entorhinal cortex. In these animals, convulsive behavior and EEG signals were analyzed. Results: The animals treated with 4-AP showed convulsive behavior and epileptiform activity 60 min after the administration. A significant increase in the protein expression of Cx 32, Cx 36 and Cx 43 was found in the HIP contralateral and ipsilateral to the site of 4-AP administration. A trend toward an increase in the mRNA of Cx 32 and Cx 43 was also found. An increase in the cellular density of Cx 32 and Cx 43 was found in the right HIP and DG, and an increase in the cellular density of oligodendrocytes in the DG and a decrease in the number of cells marked with NeuN were observed in the left HIP. Conclusions: Cx 32 and Cx 43 associated with oligodendrocytes and astrocytes had an important role in the first stages of seizures induced by 4-AP, whereas Cx36 localized to neurons could be associated with later stages. Additionally, these results contribute to our understanding of the role of connexins in acute seizures and allow us to direct our efforts to other new anticonvulsant strategies for seizure treatment.
ACCESSION #
109221474

 

Related Articles

  • SIGNAL PROCESSING: Closing the gap. Jones, Rachel // Nature Reviews Neuroscience;Oct2001, Vol. 2 Issue 10, p680 

    Discusses a study which demonstrated that axons of hippocampal neurons are electrically coupled by gap junctions. Information on spikelets; Evidence of axo-axonal gap junctions; Function of axo-axonal coupling.

  • The contribution of electrical synapses to field potential oscillations in the hippocampal formation. Posłuszny, Anna // Frontiers in Neural Circuits;Apr2014, Vol. 8, p1 

    Electrical synapses are a type of cellular membrane junction referred to as gap junctions (GJs). They provide a direct way to exchange ions between coupled cells and have been proposed as a structural basis for fast transmission of electrical potentials between neurons in the brain. For this...

  • Reciprocal Regulation of Epileptiform Neuronal Oscillations and Electrical Synapses in the Rat Hippocampus. Kinjo, Erika R.; Higa, Guilherme S. V.; Morya, Edgard; Valle, Angela C.; Kihara, Alexandre H.; Britto, Luiz R. G. // PLoS ONE;Oct2014, Vol. 9 Issue 10, p1 

    Gap junction (GJ) channels have been recognized as an important mechanism for synchronizing neuronal networks. Herein, we investigated the participation of GJ channels in the pilocarpine-induced status epilepticus (SE) by analyzing electrophysiological activity following the blockade of...

  • Independent high and low pH block of connexin 43 gap junctions. Garciarena, C. D.; Spitzer, K. W.; Swietach, P.; Moreno, A. P.; Vaughan-Jones, R. D. // Proceedings of the Physiological Society;2014, p118P 

    An abstract of the article "Independent high and low pH block of connexin 43 gap junctions" by C. D. Garciarena, K. W. Spitzer, P. Swietach, A. P. Moreno, and R. D. Vaughan-Jones is presented.

  • Gap Junctions as Therapeutic Targets in Brain Injury Following Hypoxia-Ischemia. Sahores, Macarena; Mendoza-Naranjo, Ariadna // Recent Patents on CNS Drug Discovery;Nov2008, Vol. 3 Issue 3, p209 

    Gap junctions (GJs) are highly specialized membrane structures which allow the passage of small molecules and ions between neighboring cells. Intercellular communication via GJs is a crucial mechanism that plays a central role in several pathologies. This review focuses on: i) the role of...

  • Abundance of gap junctions at glutamatergic mixed synapses in adult Mosquitofish spinal cord neurons. Serrano-Velez, Jose L.; Rodriguez-Alvarado, Melanie; Torres-Vazquez, Irma I.; Fraser, Scott E.; Yasumura, Thomas; Vanderpool, Kimberly G.; Rash, John E.; Rosa-Molinar, Eduardo // Frontiers in Neural Circuits;Jun2014, Vol. 8, p1 

    "Dye-coupling", whole-mount immunohistochemistry for gap junction channel protein connexin 35 (Cx35), and freeze-fracture replica immunogold labeling (FRIL) reveal an abundance of electrical synapses/gap junctions at glutamatergic mixed synapses in the 14th spinal segment that innervates the...

  • Under Construction: Building the Macromolecular Superstructure and Signaling Components of an Electrical Synapse. Lynn, B.; Li, Xinbo; Nagy, J. // Journal of Membrane Biology;May2012, Vol. 245 Issue 5/6, p303 

    A great deal is now known about the protein components of tight junctions and adherens junctions, as well as how these are assembled. Less is known about the molecular framework of gap junctions, but these also have membrane specializations and are subject to regulation of their assembly and...

  • Auditory Brainstem Responses in Gap Junction Beta 2 (GJB2) 35delG Mutation Carriers. Kose, Aysen; Balci, Burcu; Aksoy, Songul // Journal of International Advanced Otology;2011, Vol. 7 Issue 1, p353 

    No abstract available.

  • Roles of gap junctions, connexins, and pannexins in epilepsy. Mylvaganam, Shanthini; Ramani, Meera; Krawczyk, Michal; Carlen, Peter L. // Frontiers in Physiology;May2014, Vol. 5, p1 

    Enhanced gap junctional communication (GJC) between neurons is considered a major factor underlying the neuronal synchrony driving seizure activity. In addition, the hippocampal sharp wave ripple complexes, associated with learning and seizures, are diminished by GJC blocking agents. Although...

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics