title: Neurons synthesizing nitric oxide innervate the mammalian carotid body.
abstract: The carotid body is an arterial chemoreceptor organ sensitive to blood levels of O2, CO2 and pH. The present immunocytochemical and neurochemical study has demonstrated the presence of an extensive plexus of nitric oxide (NO)-synthesizing nerve fibers in this organ. These nitric oxide synthase (NOS)-containing axons are closely associated with parenchymal type I cells and with blood vessels in the carotid body. Denervation and retrograde tracing experiments have revealed that these fibers arise from NOS-immunoreactive and nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase-positive neuronal cell bodies located in the petrosal ganglion and the carotid body, and dispersed along the glossopharyngeal and carotid sinus nerves (CSN). Within the petrosal ganglion, these neurons are topographically segregated from the catecholaminergic cells, and they contain the neuropeptide, substance P. NOS-positive autonomic microganglial cells in the carotid body and CSN also exhibit choline acetyltransferase (ChAT) immunoreactivity. Our results suggest that nitric oxide may be a novel neuronal messenger in the mammalian carotid body involved in the modulation of chemosensory transduction and transmission in this organ.
authors.affiliation: Department of Physiology, University of Utah School of Medicine, Salt Lake City 84108.
authors.forename: Z Z
authors.initials: ZZ
authors.lastname: Wang
authors.forename: D S
authors.initials: DS
authors.lastname: Bredt
authors.forename: S J
authors.initials: SJ
authors.lastname: Fidone
authors.forename: L J
authors.initials: LJ
authors.lastname: Stensaas
mesh_terms: D000594:Amino Acid Oxidoreductases / Q000032:analysis; D000818:Animals; D002344:Carotid Body / Q000201:enzymology / Q000378:metabolism*; D002346:Carotid Sinus / Q000294:innervation; D002956:Citrulline / Q000096:biosynthesis; D003714:Denervation; D005724:Ganglia / Q000201:enzymology; D008297:Male; D008322:Mammals / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D002956:Citrulline; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases