Amino acid transporter (VIAAT, VGLUT2) and chloride cotransporter (KCC1, KCC2 and NKCC1) expression in the vestibular nuclei of intact and labyrinthectomized rat

Exp Brain Res. 2007 Oct;182(4):449-58. doi: 10.1007/s00221-007-1006-0. Epub 2007 Jun 28.

Abstract

We report the first investigation of whether unilateral labyrinthectomy in adult rats affects the expression of two amino acid transporters, vesicular glutamate transporter 2 (VGLUT2) and vesicular inhibitory amino acid transporter (VIAAT) and of chloride cotransporters (KCC1, KCC2 and NKCC1) in the intact and deafferented medial vestibular nuclei (MVN). In situ hybridization with specific radioactive oligonucleotide probes and immunofluorescent methods were used in normal and unilaterally labyrinthectomized rats at various times following the lesion: 5 h, and 1, 3 and 8 days. In normal animals, several brainstem regions including the lateral, medial, superior and inferior vestibular nuclei contained VGLUT2, VIAAT and KCC2 mRNA. In contrast, no or a very faint labeling was observed with KCC1 and NKCC1 probes. In unilaterally lesioned rats, there was no asymmetry between the two MVN with any of the oligonucleotide probes at any time after the lesion. Similarly, there were no differences in the intensity of MVN labeling between controls and lesioned animals. Finally, no over-expression of the cotransporter KCC1 and NKCC1 was found in ipsilateral or controlateral MVN in lesioned rats at any time. Immunohistochemical experiments gave similar conclusions. Our findings suggest that the recovery of the resting discharge of the deafferented MVN neurons, and consequently the functional compensation of the deficits, are not dependent on changes in the expression of amino acid transporters (VIAAT, VGLUT2), and chloride cotransporters (KCC1, KCC2 and NKCC1) or on their mRNAs.

MeSH terms

  • Amino Acid Transport Systems / genetics
  • Amino Acid Transport Systems / metabolism*
  • Animals
  • Disease Models, Animal
  • Gene Expression Regulation / physiology*
  • Male
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Long-Evans
  • Sodium-Potassium-Chloride Symporters
  • Solute Carrier Family 12, Member 2
  • Symporters / genetics
  • Symporters / immunology*
  • Time Factors
  • Vesicular Glutamate Transport Protein 2
  • Vesicular Inhibitory Amino Acid Transport Proteins / genetics
  • Vesicular Inhibitory Amino Acid Transport Proteins / metabolism
  • Vestibular Nuclei / cytology
  • Vestibular Nuclei / metabolism*
  • Vestibule, Labyrinth / injuries*

Substances

  • Amino Acid Transport Systems
  • RNA, Messenger
  • Slc12a2 protein, rat
  • Slc17a6 protein, rat
  • Slc32a1 protein, rat
  • Sodium-Potassium-Chloride Symporters
  • Solute Carrier Family 12, Member 2
  • Symporters
  • Vesicular Glutamate Transport Protein 2
  • Vesicular Inhibitory Amino Acid Transport Proteins
  • potassium-chloride symporters