Changes in muscle tone are regulated by D1 and D2 dopamine receptors in the ventral striatum and D1 receptors in the substantia nigra

Kim M. Hemsley, Ann D. Crocker

Research output: Contribution to journalArticle

22 Citations (Scopus)


Muscle rigidity associated with antipsychotic drug treatment is believed to result from reduced striatal dopamine neurotransmission. In the current study the regulatory roles of dopamine D1 and D2 receptor subfamilies in the dorsal (DSTR) and ventral striatum (VSTR) and substantia nigra (SN) were investigated on muscle tone, assessed as increases in tonic electromyographic (EMG) activity. Rats were injected with the irreversible D1/D2 antagonist N-ethoxycarbonyl-2-ethoxy, -1,2-dihydroquinoline (EEDQ), the reversible D1 antagonist SCH23390, or D2 antagonist sulpiride. Increased EMG activity was observed following injection of EEDQ and SCH23390 into the SN or VSTR, and sulpiride into the VSTR. Mapping, using quantitative autoradiographic analysis of dopamine receptor occupancy after striatal injections, showed D1 and D2 receptors in discrete ventral sites were associated with EMG increases. Overall the results support roles for dopamine D1 and D2 receptors in the ventral striatum, and D1 receptors in the substantia nigra, in the regulation of muscle tone.

Original languageEnglish
Pages (from-to)514-526
Number of pages13
Issue number4
Publication statusPublished - 21 Sep 2001


  • Antipsychotic Drugs
  • Dopamine Receptors
  • Extrapyramidal Side Effects
  • Muscle Rigidity
  • Substantia Nigra
  • Ventral Striatum

ASJC Scopus subject areas

  • Pharmacology
  • Psychiatry and Mental health

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