Protein expression of small conductance calcium-activated potassium channels is altered in inferior colliculus neurons of the genetically epilepsy-prone rat

Brain Res. 2009 May 13:1270:107-11. doi: 10.1016/j.brainres.2009.02.034. Epub 2009 Feb 27.

Abstract

The genetically epilepsy-prone rat (GEPR) exhibits inherited predisposition to sound stimuli-induced generalized tonic-clonic seizures (audiogenic reflex seizures) and is a valid model to study the physiopathology of epilepsy. In this model, the inferior colliculus (IC) exhibits enhanced neuronal firing that is critical in the initiation of reflex audiogenic seizures. The mechanisms underlying IC neuronal hyperexcitability that leads to seizure susceptibility are not as yet fully understood. The present report shows that the levels of protein expression of SK1 and SK3 subtypes of the small conductance Ca2+-activated K+ channels were significantly decreased, while SK2 channel proteins were increased in IC neurons of seizure-naive GEPR-3s (SN-GEPR-3), as compared to control Sprague-Dawley rats. No significant change was found in the expression of BK channel proteins in IC neurons of SN-GEPR-3s. Single episode of reflex audiogenic seizures in the GEPR-3s did not significantly alter the protein expression of SK1-3 and BK channels in IC neurons compared to SN-GEPR-3s. Thus, downregulation of SK1 and SK3 channels and upregulation of SK2 channels provide direct evidence that these Ca2+-activated K+ channels play important roles in IC neuronal hyperexcitability that leads to inherited seizure susceptibility in the GEPR.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Disease Models, Animal
  • Down-Regulation / physiology
  • Epilepsy, Reflex / genetics
  • Epilepsy, Reflex / pathology*
  • Epilepsy, Reflex / physiopathology*
  • Genetic Predisposition to Disease
  • Inferior Colliculi / pathology*
  • Inferior Colliculi / physiopathology*
  • Male
  • Rats
  • Rats, Mutant Strains
  • Small-Conductance Calcium-Activated Potassium Channels / genetics*
  • Small-Conductance Calcium-Activated Potassium Channels / metabolism
  • Up-Regulation / physiology

Substances

  • Kcnn1 protein, rat
  • Kcnn2 protein, rat
  • Kcnn3 protein, rat
  • Small-Conductance Calcium-Activated Potassium Channels