Mu-opioid receptors selectively regulate basal inhibitory transmission in the central amygdala: lack of ethanol interactions.
Journal Article (Journal Article)
Endogenous opioid systems are implicated in the actions of ethanol. For example, mu-opioid receptor (MOR) knockout (KO) mice self-administer less alcohol than the genetically intact counterpart wild-type (WT) mice (Roberts et al., 2000). MOR KO mice also exhibit less anxiety-like behavior than WT mice (Filliol et al., 2000). To investigate the neurobiological mechanisms underlying these behaviors, we examined the effect of ethanol in brain slices from MOR KO and WT mice using sharp-electrode and whole-cell patch recording techniques. We focused our study in the central nucleus of the amygdala (CeA) because it is implicated in alcohol drinking behavior and stress behavior. We found that the amplitudes of evoked inhibitory postsynaptic currents (IPSCs) or inhibitory postsynaptic potentials (IPSPs) were significantly greater in MOR KO mice than WT mice. In addition, the baseline frequencies of spontaneous and miniature GABA(A) receptor-mediated inhibitory postsynaptic currents were significantly greater in CeA neurons from MOR KO than WT mice. However, ethanol enhancements of evoked IPSP and IPSC amplitudes and the frequency of miniature IPSCs were comparable between WT and MOR KO mice. Baseline spontaneous and miniature excitatory postsynaptic currents (EPSCs) and ethanol effects on EPSCs were not significantly different between MOR KO and WT mice. Based on knowledge of CeA circuitry and projections, we hypothesize that the role of MOR- and GABA receptor-mediated mechanisms in CeA underlying reinforcing effects of ethanol operate independently, possibly through pathway-specific responses within CeA.
Full Text
Duke Authors
Cited Authors
- Kang-Park, M-H; Kieffer, BL; Roberts, AJ; Roberto, M; Madamba, SG; Siggins, GR; Moore, SD
Published Date
- January 2009
Published In
Volume / Issue
- 328 / 1
Start / End Page
- 284 - 293
PubMed ID
- 18854491
Pubmed Central ID
- PMC2685907
Electronic International Standard Serial Number (EISSN)
- 1521-0103
Digital Object Identifier (DOI)
- 10.1124/jpet.108.140749
Language
- eng
Conference Location
- United States