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.
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.
Minami
M
M
Department of Molecular Pharmacology, Faculty of Pharmaceutical Sciences, Kyoto University, Japan.
Maekawa
K
K
Yabuuchi
K
K
Satoh
M
M
D000818:Animals; D015152:Blotting, Northern; D005727:Ganglia, Spinal / Q000502:physiology*; D017403:In Situ Hybridization; D008297:Male; D011498:Protein Precursors / Q000096:biosynthesis*; D015347:RNA Probes; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011957:Receptors, Opioid / Q000096:biosynthesis*; D017465:Receptors, Opioid, delta / Q000096:biosynthesis; D017473:Receptors, Opioid, kappa / Q000096:biosynthesis; D017450:Receptors, Opioid, mu / Q000096:biosynthesis; D013373:Substance P / Q000378:metabolism; D015320:Tachykinins / Q000096:biosynthesis*
D011498:Protein Precursors; D015347:RNA Probes; D012333:RNA, Messenger; D011957:Receptors, Opioid; D017465:Receptors, Opioid, delta; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; D015320:Tachykinins; C044206:preprotachykinin; D013373:Substance P