N-methyl-D-aspartate receptors are expressed by intrinsic neurons of rat larynx and esophagus.
Overactivation of N-methyl-D-aspartate receptors (NMDAR), a mechanism of central neurotoxicity, has recently been shown to increase airway responsiveness in rat lungs. NMDAR have not been localized in the airways, but neurons of the myenteric plexus in the rat express mRNA for NMDAR. Furthermore, a population of glutamate-containing cell bodies in the nucleus ambiguus projects to the rat larynx. On this basis, we hypothesized that some postganglionic parasympathetic neurons of the larynx, trachea and esophagus may express NMDAR. Sections of rat larynx, trachea and esophagus were immunocytochemically labeled for NMDAR subtype 2B using a specific antibody. NMDAR immunoreactivity was observed in cell bodies of individual neurons located in the submucosa and on the external surface of skeletal muscle in the larynx and also in neurons of the esophageal plexus. All NMDAR-positive nerve cell bodies also contained immunoreactivity for vasoactive intestinal peptide (VIP) and some were immunoreactive for nitric oxide synthase (NOS). None of the cell bodies of the tracheal plexus contained NMDAR immunoreactivity. The findings demonstrate that NMDAR are expressed in neurons of the rat larynx and esophagus and their activation may be associate with VIP or NO release.
Robertson
B S
BS
Department of Anatomy, West Virginia University, Morgantown 26506, USA.
Satterfield
B E
BE
Said
S I
SI
Dey
R D
RD
D000818:Animals; D004947:Esophagus / Q000294:innervation*; D007150:Immunohistochemistry; D007823:Laryngeal Nerves / Q000378:metabolism*; D008297:Male; D018482:Muscle, Skeletal / Q000294:innervation; D009412:Nerve Fibers / Q000378:metabolism / Q000648:ultrastructure; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000032:analysis; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D011916:Rats, Inbred F344; D016194:Receptors, N-Methyl-D-Aspartate / Q000096:biosynthesis*; D014132:Trachea / Q000294:innervation*; D014158:Transcription, Genetic; D014660:Vasoactive Intestinal Peptide / Q000032:analysis
D012333:RNA, Messenger; D016194:Receptors, N-Methyl-D-Aspartate; D014660:Vasoactive Intestinal Peptide; D019001:Nitric Oxide Synthase