Distribution of delta opioid receptor-expressing neurons in the mouse hippocampus

Neuroscience. 2012 Sep 27;221:203-13. doi: 10.1016/j.neuroscience.2012.06.023. Epub 2012 Jun 28.


Delta opioid receptors participate to the control of chronic pain and emotional responses. Recent data also identified their implication in spatial memory and drug-context associations pointing to a critical role of hippocampal delta receptors. We examined the distribution of delta receptor-expressing cells in the hippocampus using fluorescent knock-in mice that express a functional delta receptor fused at its carboxyterminus with the green fluorescent protein in place of the native receptor. Colocalization with markers for different neuronal populations was performed by immunohistochemical detection. Fine mapping in the dorsal hippocampus confirmed that delta opioid receptors are mainly present in GABAergic neurons. Indeed, they are mostly expressed in parvalbumin-immunopositive neurons both in the Ammon's horn and dentate gyrus. These receptors, therefore, most likely participate in the dynamic regulation of hippocampal activity.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Female
  • Glutamate Decarboxylase / metabolism
  • Green Fluorescent Proteins / genetics
  • Hippocampus / anatomy & histology
  • Hippocampus / cytology*
  • Humans
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Nerve Tissue Proteins / metabolism
  • Neurons / metabolism*
  • Parvalbumins / metabolism
  • Receptors, Opioid, delta / genetics
  • Receptors, Opioid, delta / metabolism*
  • Somatostatin / metabolism
  • Vesicular Glutamate Transport Protein 1 / metabolism
  • Vesicular Glutamate Transport Protein 2 / metabolism


  • Nerve Tissue Proteins
  • Parvalbumins
  • Receptors, Opioid, delta
  • Vesicular Glutamate Transport Protein 1
  • Vesicular Glutamate Transport Protein 2
  • enhanced green fluorescent protein
  • Green Fluorescent Proteins
  • Somatostatin
  • Glutamate Decarboxylase
  • glutamate decarboxylase 2