Double in situ hybridization study on coexistence of mu-, delta- and kappa-opioid receptor mRNAs with preprotachykinin A mRNA in the rat dorsal root ganglia

Brain Res Mol Brain Res. 1995 Jun;30(2):203-10. doi: 10.1016/0169-328x(94)00290-u.


Coexistence of the mRNA for each subtype of opioid receptor (OPR) with the mRNA for preprotachykinin A (PPTA), a precursor protein of substance P (SP), in the rat dorsal root ganglia was examined by double in situ hybridization technique. About 90% and 30% of PPTA mRNA-positive neurons expressed mu- and kappa-OPR mRNAs at high level, respectively. However, only about 3% of PPTA mRNA-positive neurons expressed delta-OPR mRNA at high level. These results suggest that mu- and kappa-OPRs exist on most of and a part of the primary afferent terminals containing SP, respectively. On the other hand, among the neurons which highly expressed mu-, delta- or kappa-OPR mRNA, PPTA mRNA was not expressed in about 58%, 95% or 24% of those neurons, respectively. These findings suggest the possibility that OPRs co-exist with other neurotransmitters and/or neuromodulators than SP in the primary afferent neurons.

MeSH terms

  • Animals
  • Blotting, Northern
  • Ganglia, Spinal / physiology*
  • In Situ Hybridization
  • Male
  • Protein Precursors / biosynthesis*
  • RNA Probes
  • RNA, Messenger / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Opioid / biosynthesis*
  • Receptors, Opioid, delta / biosynthesis
  • Receptors, Opioid, kappa / biosynthesis
  • Receptors, Opioid, mu / biosynthesis
  • Substance P / metabolism
  • Tachykinins / biosynthesis*


  • Protein Precursors
  • RNA Probes
  • RNA, Messenger
  • Receptors, Opioid
  • Receptors, Opioid, delta
  • Receptors, Opioid, kappa
  • Receptors, Opioid, mu
  • Tachykinins
  • preprotachykinin
  • Substance P