title: Nitrergic innervation and nitrergic cells in arteriovenous anastomoses.
abstract: Nitrergic innervation and nitrergic epithelioid cells were studied in arteriovenous anastomoses of the tongue, ear, eye, and glomus organ of the finger in different species (rat, rabbit, dog, and man), by means of immunohistochemistry for nitric oxide synthase and enzyme histochemistry utilizing the catalytic activity of this enzyme (the NADPH-diaphorase reaction). Nitrergic perivascular fibers of the tongue were concentrated along the arterial tree and were maximal at the arteriovenous anastomoses in all species. Generally, fewer fibers were located around comparable segments of the episcleral eye vasculature. Only a few nitrergic fibers were found in the canine and rabbit ear, and in the glomus organ of the human finger; however, epithelioid cells in the tunica media of arteriovenous anastomoses of these organs were NADPH-diaphorase-positive and were moderately immunoreactive for nitric oxide synthase. In the epithelioid cells, the reaction product of the NADPH-diaphorase could also be demonstrated by transmission electron microscopy. The epithelioid cells were negative for the panneural and neuroendocrine marker PGP 9.5 confirming the myocytotic nature of these nitrergic cells. Thus, nitric oxide might play a role in mediating the vessel tone of arteriovenous anastomoses via nitrergic nerves or epithelioid cells.
authors.affiliation: Anatomisches Institut (Lehrstuhl I), Universität Erlangen-Nürnberg, Germany.
authors.forename: R H
authors.initials: RH
authors.lastname: Funk
authors.forename: B
authors.initials: B
authors.lastname: Mayer
authors.forename: J
authors.initials: J
authors.lastname: Wörl
mesh_terms: D000594:Amino Acid Oxidoreductases / Q000032:analysis; D000818:Animals; D001163:Arteriovenous Anastomosis / Q000166:cytology* / Q000294:innervation*; D004285:Dogs; D004423:Ear / Q000098:blood supply; D005123:Eye / Q000098:blood supply; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D009252:NADPH Dehydrogenase / Q000032:analysis; D009412:Nerve Fibers / Q000648:ultrastructure*; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar; D013869:Thiolester Hydrolases / Q000032:analysis; D014059:Tongue / Q000098:blood supply; D043222:Ubiquitin Thiolesterase
chemical_list: D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases; D009252:NADPH Dehydrogenase; D013869:Thiolester Hydrolases; D043222:Ubiquitin Thiolesterase