Involvement of A5/A7 noradrenergic neurons and B2 serotonergic neurons in nociceptive processing: a fiber photometry study

Shunpei Moriya, Akira Yamashita, Daiki Masukawa, Junichi Sakaguchi, Yoko Ikoma, Yoshimune Sameshima, Yuki Kambe, Akihiro Yamanaka, Tomoyuki Kuwaki

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


In the central nervous system, the A6 noradrenaline (NA) and the B3 serotonin (5-HT) cell groups are well-recognized players in the descending antinociceptive system, while other NA/5-HT cell groups are not well characterized. A5/A7 NA and B2 5-HT cells project to the spinal horn and form descending pathways. We recorded G-CaMP6 green fluorescence signal intensities in the A5/A7 NA and the B2 5-HT cell groups of awake mice in response to acute tail pinch stimuli, acute heat stimuli, and in the context of a non-noxious control test, using fiber photometry with a calcium imaging system. We first introduced G-CaMP6 in the A5/A7 NA or B2 5-HT neuronal soma, using transgenic mice carrying the tetracycline-controlled transactivator transgene under the control of either a dopamine β-hydroxylase or a tryptophan hydroxylase-2 promoters and by the site-specific injection of adeno-associated virus (AAV-TetO(3G)-G-CaMP6). After confirming the specific expression patterns of G-CaMP6, we recorded G-CaMP6 green fluorescence signals in these sites in awake mice in response to acute nociceptive stimuli. G-CaMP6 fluorescence intensity in the A5, A7, and B2 cell groups was rapidly increased in response to acute nociceptive stimuli and soon after, it returned to baseline fluorescence intensity. This was not observed in the non-noxious control test. The results indicate that acute nociceptive stimuli rapidly increase the activities of A5/A7 NA or B2 5-HT neurons but the non-noxious stimuli do not. The present study suggests that A5/A7 NA or B2 5-HT neurons play important roles in nociceptive processing in the central nervous system. We suggest that A5/A7/B2 neurons may be new therapeutic targets. All performed procedures were approved by the Institutional Animal Use Committee of Kagoshima University (MD17105) on February 22, 2018.

Original languageEnglish
Pages (from-to)881-886
Number of pages6
JournalNeural Regeneration Research
Issue number4
Publication statusPublished - 2022 Apr
Externally publishedYes


  • A5 NA neurons
  • A7 NA neurons
  • B2 5-HT neurons
  • DBH-tTA mice
  • Fiber photometry
  • G-CaMP6
  • MCherry
  • Monoaminergic signaling
  • Nociception
  • TPH-tTA mice

ASJC Scopus subject areas

  • Developmental Neuroscience


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