Physiological bases of the K+ and the glutamate/GABA hypotheses of epilepsy

Epilepsy Res. 2014 Aug;108(6):995-1012. doi: 10.1016/j.eplepsyres.2014.04.001. Epub 2014 Apr 21.

Abstract

Epilepsy is a heterogeneous family of neurological disorders that manifest as seizures, i.e. the hypersynchronous activity of large population of neurons. About 30% of epileptic patients do not respond to currently available antiepileptic drugs. Decades of intense research have elucidated the involvement of a number of possible signaling pathways, however, at present we do not have a fundamental understanding of epileptogenesis. In this paper, we review the literature on epilepsy under a wide-angle perspective, a mandatory choice that responds to the recurrent and unanswered question about what is epiphenomenal and what is causal to the disease. While focusing on the involvement of K+ and glutamate/GABA in determining neuronal hyperexcitability, emphasis is given to astrocytic contribution to epileptogenesis, and especially to loss-of-function of astrocytic glutamine synthetase following reactive astrogliosis, a hallmark of epileptic syndromes. We finally introduce the potential involvement of abnormal glycogen synthesis induced by excess glutamate in increasing susceptibility to seizures.

Keywords: Epilepsy; GABA; Glutamate; Glycogen; Potassium.

Publication types

  • Research Support, N.I.H., Extramural
  • Review

MeSH terms

  • Animals
  • Astrocytes / physiology
  • Brain / physiopathology*
  • Epilepsy / physiopathology*
  • Glutamic Acid / metabolism*
  • Glycogen / metabolism
  • Humans
  • Models, Neurological*
  • Neurons / physiology
  • Potassium / metabolism*
  • gamma-Aminobutyric Acid / metabolism*

Substances

  • Glutamic Acid
  • gamma-Aminobutyric Acid
  • Glycogen
  • Potassium