Regulation of the concentration of dynorphin A1-8 in the striatonigral pathway by the dopaminergic system

S. Li, S. P. Sivam, J. S. Hong

Research output: Contribution to journalArticle

65 Scopus citations

Abstract

The purpose of this study was to explore the dopaminergic control of the striatonigral dynorphin system by measuring the levels of dynorphin A1-8-like immunoreactivity (DN-LI) after repeated injections of a dopaminergic receptor agonist or antagonist. Seven daily injections of different doses of apomorphine (0.5, 1.0, 2.5 and 5.0 mg/kg, s.c.) caused a significant dose-related increase of DN-LI in the striatum (26, 34, 63, 85% over control at each corresponding dose). Similar increases were observed in the substantia nigra (22, 52, 50 and 62% over control). In another experiment, rats received 5 mg/kg of apomorphine for 1, 3, and 7 days. There was a significant time-related increase in DN-LI both in the striatum (37, 50 and 85% over control at each corresponding period) and in the substantia nigra (32, 78 and 62%). Repeated administration of haloperidol (1 mg/kg, i.p.) failed to change the striatal level of DN-LI, but, when given at the same time as apomorphine, significantly attenuated the effect of apomorphine. These results suggest that dopamine exerts a modulatory influence on the metabolism of dynorphin in the striatonigral pathway.

Original languageEnglish (US)
Pages (from-to)390-392
Number of pages3
JournalBrain research
Volume398
Issue number2
DOIs
StatePublished - Nov 29 1986
Externally publishedYes

Keywords

  • Dopamine
  • Dynorphin
  • Striatonigral pathway

ASJC Scopus subject areas

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

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