Carbon monoxide: A role in carotid body chemoreception

Nanduri R. Prabhakar, Jay L. Dinerman, Faton H. Agani, Solomon H. Snyder

Research output: Contribution to journalArticlepeer-review

177 Scopus citations


Carbon monoxide (CO), produced endogenously by heme oxygenase, has been implicated as a neuronal messenger. Carotid bodies are sensory organs that regulate ventilation by responding to alterations of blood oxygen, CO2, and pH. Changes in blood gases are sensed by glomus cells in the carotid body that synapse on afferent terminals of the carotid sinus nerve that projects to respiratory-related neurons in the brainstem. Using immunocytochemistry, we demonstrate that heme oxygenase 2 is localized to glomus cells in the cat and rat carotid bodies. Physiological studies show that zinc protoporphyrin IX, a potent heme oxygenase inhibitor, markedly increases carotid body sensory activity, while copper protoporphyrin IX, which does not inhibit the enzyme, is inactive. Exogenous CO reverses the stimulatory effects of zinc protoporphyrin IX. These results suggest that glomus cells are capable of synthesizing CO and endogenous CO appears to be a physiologic regulator of carotid body sensory activity.

Original languageEnglish (US)
Pages (from-to)1994-1997
Number of pages4
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number6
StatePublished - Mar 14 1995


  • heme oxygenase 2
  • zinc protoporphyrin IX

ASJC Scopus subject areas

  • General


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