Affordable Access

Kappa- and delta-opioid receptor functional activities are increased in the caudate putamen of cannabinoid CB1 receptor knockout mice.

Authors
  • Urigüen, Leyre
  • Berrendero, Fernando
  • Ledent, Catherine
  • Maldonado, Rafael
  • Manzanares, Jorge
Type
Published Article
Journal
The European journal of neuroscience
Publication Date
Oct 01, 2005
Volume
22
Issue
8
Pages
2106–2110
Identifiers
PMID: 16262648
Source
Medline
License
Unknown

Abstract

The purpose of this study was to examine the functional interaction between endogenous opioid and cannabinoid receptor systems in the caudate putamen and nucleus accumbens. We therefore examined by autoradiography the functional activity and density of micro-, kappa- and delta-opioid receptors in both brain regions of cannabinoid CB1 receptor knockout mice. Functional activity was estimated by measuring agonist-stimulated [35S]GTPgammaS binding. Results showed that deletion of the CB1 cannabinoid receptor markedly increased kappa-opioid (50%) and delta-opioid (42%) receptor activities whereas no differences were found in micro-opioid receptor in the caudate putamen. In contrast, binding autoradiography showed a similar density of micro-, kappa- and delta-opioid receptors between mutant and wild-type mice. No differences were found in densities or activities of micro-, kappa- and delta-opioid receptors between mutant and wild-type mice in the nucleus accumbens. Taken together, our results revealed that deletion of CB1 cannabinoid receptors produced a pronounced increase in the activity of kappa- and delta-opioid receptors in the caudate putamen. This endogenous interaction between opioid and cannabinoid receptors may be relevant to further understand a variety of neuroadaptative processes involving the participation of opioid receptors, such as motor behaviour, emotional responses and drug dependence.

Report this publication

Statistics

Seen <100 times