Local muscimol disinhibits mesolimbic dopaminergic activity as examined by brain microdialysis and Fos immunohistochemistry

Brain Res. 1997 Sep 5;767(2):356-60. doi: 10.1016/s0006-8993(97)00474-5.

Abstract

Infusion of muscimol (5 X 10[-5] M, 60 min) into the nucleus accumbens (NAC) through a dialysis membrane caused a significant increase in extracellular dopamine (DA) and its metabolite, 3,4-dihydroxyphenylacetic acid (DOPAC). Fos-like immunoreactivity induced by intra-NAC infusion of muscimol was seen ipsilaterally in many accumbofugal target areas, but no Fos-positive neurons were seen in the vicinity of the dialysis membrane in the NAC. Sequential staining of Fos and tyrosine hydroxylase (TH) immunoreactivities revealed that a portion of A10 dopaminergic neurons were double-labelled. These results suggest that muscimol in the NAC disinhibits mesolimbic DA neuronal activity possibly through activity of the accumbofugal GABA neuron system.

MeSH terms

  • 3,4-Dihydroxyphenylacetic Acid / metabolism
  • Animals
  • Dopamine / metabolism*
  • Immunohistochemistry
  • Male
  • Microdialysis
  • Muscimol / pharmacology*
  • Nerve Tissue Proteins / analysis*
  • Nucleus Accumbens / drug effects*
  • Nucleus Accumbens / metabolism
  • Proto-Oncogene Proteins c-fos / analysis*
  • Rats
  • Rats, Wistar

Substances

  • Nerve Tissue Proteins
  • Proto-Oncogene Proteins c-fos
  • 3,4-Dihydroxyphenylacetic Acid
  • Muscimol
  • Dopamine