Orexin A and B in the rat superior salivatory nucleus

Tadasu Sato, Takehiro Yajima, Masako Fujita, Motoi Kobashi, Hiroyuki Ichikawa, Ryusuke Yoshida, Yoshihiro Mitoh

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3 Citations (Scopus)


Orexin (OX), which regulates sleep and wakefulness and feeding behaviors has 2 isoforms, orexin-A and -B (OXA and OXB). In this study, the distribution of OXA and OXB was examined in the rat superior salivatory nucleus (SSN) using retrograde tracing and immunohistochemical and methods. OXA- and OXB-immunoreactive (-ir) nerve fibers were seen throughout the SSN. These nerve fibers surrounded SSN neurons retrogradely labeled with Fast blue (FB) from the corda-lingual nerve. FB-positive neurons had pericellular OXA- (47.5%) and OXB-ir (49.0%) nerve fibers. Immunohistochemistry for OX receptors also demonstrated the presence of OX1R and OX2R in FB-positive SSN neurons. The majority of FB-positive SSN neurons contained OX1R- (69.7%) or OX2R-immunoreactivity (57.8%). These neurons had small and medium-sized cell bodies. In addition, half of FB-positive SSN neurons which were immunoreactive for OX1R (47.0%) and OX2R (52.2%) had pericellular OXA- and OXB-ir nerve fibers, respectively. Co-expression of OX1R- and OX2R was common in FB-positive SSN neurons. The present study suggests a possibility that OXs regulate the activity of SSN neurons through OX receptors.

Original languageEnglish
Article number102712
JournalAutonomic Neuroscience: Basic and Clinical
Publication statusPublished - 2020 Nov


  • Chorda-lingual nerve
  • Immunohistochemistry
  • Orexin
  • Orexin receptor
  • Preganglionic neuron
  • Superior salivatory nucleus


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