Journal of Molecular Neuroscience

, Volume 24, Issue 2, pp 307–314

Differential time course of effects of κ-opioid agonist treatment on dynorphin a levels and κ-opioid receptor density

  • Claudio D’Addario
  • Manuela Di Benedetto
  • Sari Izenwasser
  • Sanzio Candeletti
  • Patrizia Romualdi
Original Article

DOI: 10.1385/JMN:24:2:307

Cite this article as:
D’Addario, C., Di Benedetto, M., Izenwasser, S. et al. J Mol Neurosci (2004) 24: 307. doi:10.1385/JMN:24:2:307

Abstract

The effects of κ-opioid agonist treatment on κ-opioid receptor density and on dynorphin A levels in the rat brain were studied. Rats were treated with the selective κ-opioid agonist U-69593 or vehicle for 5 d. Dynorphin A levels and κ-opioid receptor binding were measured on day 8 (3 d after the last injection) or 22 (17 d after the last injection). On day 8, κ-opioid receptor density was increased in the hypothalamus of rats treated with U-69593; there were no changes in the frontal cortex or caudate putamen. In contrast, there was an increase in dynorphin A levels in the frontal cortex and no changes in hypothalamus and caudate putamen in response to U-69593. On day 22, Bmax was decreased in frontal cortex and caudate putamen of U-69593-treated rats, whereas dynorphin A levels were increased in the caudate putamen and in the frontal cortex. These findings suggest that κ-opioid receptor agonist treatment has long-term, continually changing effects on the κ-opioid system.

Index Entries

Opioids κ-receptor dynorphin A U-69593 rat 

Copyright information

© Humana Press Inc 2004

Authors and Affiliations

  • Claudio D’Addario
  • Manuela Di Benedetto
  • Sari Izenwasser
    • 2
  • Sanzio Candeletti
  • Patrizia Romualdi
    • 1
  1. 1.Department of PharmacologyUniversity of BolognaBolognaItaly
  2. 2.Department of Psychiatry and Behavioral SciencesUniversity of Miami School of MedicineMiami

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