Enhanced expression of the neuronal K+/Cl- cotransporter, KCC2, in spontaneously depressed Flinders Sensitive Line rats

F. Matrisciano, C. Nasca, G. Molinaro, B. Riozzi, S. Scaccianoce, M. A. Raggi, L. Mercolini, F. Biagioni, A. A. Mathè, E. Sanna, E. Maciocco, M. Pignatelli, G. Biggio, F. Nicoletti

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

We used Flinder Sensitive Line (FSL) rats, a genetic model of unipolar depression, to examine whether changes in central GABAergic transmission are associated with a depressed phenotype. FSL rats showed an increased behavioral response to low doses of diazepam, as compared to either Sprague Dawley (SD) or Flinder Resistant Line (FRL) rats used as controls. Diazepam at a dose of 0.3 mg/kg, i.p., induced a robust impairment of motor coordination in FSL rats, but was virtually inactive in SD or FRL rats. The increased responsiveness of FSL rats was not due to changes in the brain levels of diazepam or its active metabolites, or to increases in the number or affinity of benzodiazepine recognition sites, as shown by the analysis of [3H]-flunitrazepam binding in the hippocampus, cerebral cortex or cerebellum. We therefore examined whether FSL rats differed from control rats for the expression levels of the K+/Cl- cotransporter, KCC2, which transports Cl- ions out of neurons, thus creating the concentration gradient that allows Cl- influx through the anion channel associated with GABAA receptors. Combined immunoblot and immunohistochemical data showed a widespread increase in KCC2 expression in FSL rats, as compared with control rats. The increase was more prominent in the cerebellum, where KCC2 was largely expressed in the granular layer. These data raise the interesting possibility that a spontaneous depressive state in animals is associated with an amplified GABAergic transmission in the CNS resulting from an enhanced expression of KCC2.

Original languageEnglish (US)
Pages (from-to)112-120
Number of pages9
JournalBrain Research
Volume1325
DOIs
StatePublished - Apr 14 2010

Keywords

  • Benzodiazepine
  • Depression
  • Flinder Sensitive Line rat
  • KCC2

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology

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    Matrisciano, F., Nasca, C., Molinaro, G., Riozzi, B., Scaccianoce, S., Raggi, M. A., Mercolini, L., Biagioni, F., Mathè, A. A., Sanna, E., Maciocco, E., Pignatelli, M., Biggio, G., & Nicoletti, F. (2010). Enhanced expression of the neuronal K+/Cl- cotransporter, KCC2, in spontaneously depressed Flinders Sensitive Line rats. Brain Research, 1325, 112-120. https://doi.org/10.1016/j.brainres.2010.02.017