Distribution and innervation of putative arterial chemoreceptors in the bullfrog (Rana catesbeiana)

Catalina Reyes*, Angelina Y. Fong, Dee L. Brink, William K. Milsom

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


Peripheral arterial chemoreceptors have been located previously in the carotid labyrinth, the aortic arch, and the pulmocutaneous artery of frogs. In the present study we used cholera toxin B neuronal tract tracing and immunohistochemical markers for cholinergic cells (vesicular acetylcholine transporter [VAChT]), tyrosine hydroxylase (TH), and serotonin (5HT) to identify putative O2-sensing cells in Rana catesbeiana. We found potential O2-sensing cells in all three vascular areas innervated by branches of the vagus nerve, whereas only cells in the carotid labyrinth were innervated by the glossopharyngeal nerve. Cells containing either 5HT or TH were found in all three sites, whereas cells containing both neurotransmitters were found only in the carotid labyrinth. Cell bodies containing VAChT were not found at any site. The morphology and innervation of putative O2-sensing cells were similar to those of glomus cells found in other vertebrates. The presence of 5HT- and TH-immunoreactive cells in the aorta, pulmocutaneous artery, and carotid labyrinth appears to reflect a phylogenetic transition between the major neurotransmitter seen in the putative O2-sensing cells of fish (5HT) and those found in the glomus cells of mammals (acetylcholine, adenosine, and catecholamines).

Original languageEnglish
Pages (from-to)3754-3774
Number of pages21
JournalJournal of Comparative Neurology
Issue number16
Publication statusPublished - 1 Nov 2014
Externally publishedYes


  • Acetylcholine
  • Catecholamines
  • Chemoreception
  • Frogs
  • Hypoxia
  • Oxygen-sensing cells
  • Serotonin


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