The effects of an irreversible dopamine receptor antagonist, N- ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ), on the regulation of muscle tone in the rat: The role of the substantia nigra

Kim M. Hemsley, Ann D. Crocker

Research output: Contribution to journalArticle

15 Citations (Scopus)


Recent evidence has questioned the view that the increased muscle tone of Parkinson's disease results solely from reduced release of dopamine in the striatum, by emphasising the important role of the substantia nigra. The aim of the current study was to compare the effects on muscle tone of inactivating D1 and D2 dopamine receptors throughout the brain with those seen following their inactivation only in the substantia nigra. Inactivation of dopamine receptors by N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline injected either intraperitoneally, or bilaterally into the substantia nigra, resulted in similar increases in muscle tone, measured as changes in tonic electromyographic (EMG) activity. The magnitude and onset of EMG increases was related to the level of dopamine receptor inactivation. The results are consistent with the hypothesis that nigral dopamine mechanisms play a key role in the maintenance of muscle tone.

Original languageEnglish
Pages (from-to)77-80
Number of pages4
JournalNeuroscience Letters
Issue number2
Publication statusPublished - 24 Jul 1998


  • Basal ganglia
  • Dopamine receptor
  • Muscle tone
  • N- Ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline
  • Rat
  • Substantia nigra

ASJC Scopus subject areas

  • Neuroscience(all)

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