Nonadrenergic innervation of the rat laryngeal vasculature.
In order to gain a better understanding of the central and local control of laryngeal blood flow, the vascular innervation to the rat laryngeal muscles was examined. To visualize the vascular network, the animals were perfused with a gelatin/India ink solution. The larynges were removed and fixed. The superior laryngeal, cricothyroid, and inferior laryngeal arteries (all branch off the superior thyroid artery) were dissected in continuity into their respective muscles. Specimens were reacted in toto using immunohistochemical techniques for the presence of neuropeptide-Y (NPY), vasoactive intestinal peptide (VIP), calcitonin gene related peptide (CGRP), and neuronal nitric oxide synthase (NOS-1). Results show that all of the laryngeal vasculature is richly innervated by fibers containing these peptides. Qualitatively, the most prominent of these is NPY in association with the superior and the inferior laryngeal arteries, followed by VIP and NOS-1, and finally CGRP distributed equally on all the vessels. Immunopositive fibers are found along the entire course of the feeding arteries, beginning with the superior thyroid artery and continuing down to small arterioles into the terminal vascular beds. These peptides can act as vasodilators, vasoconstrictors, and/or neuromodulators and may work synergistically or antagonistically with other transmitters in controlling laryngeal blood flow. Their effects are dependent on the specific vascular bed in question, that is, in some areas they are vasodilators, in others vasoconstrictors, and in other neuromodulators. What effects they have on the laryngeal vasculature and how they interact within the larynx have yet to be determined.
Lyon
M J
MJ
Department of Otolaryngology, SUNY Upstate Medical University, Syracuse, New York 13210, USA. lyonm@mail.upstate.edu
D000818:Animals; D001158:Arteries / Q000294:innervation* / Q000378:metabolism; D001160:Arterioles / Q000294:innervation / Q000378:metabolism; D015740:Calcitonin Gene-Related Peptide / Q000032:analysis; D005780:Gelatin; D007150:Immunohistochemistry; D007281:Ink; D007830:Larynx / Q000098:blood supply*; D009130:Muscle, Smooth / Q000098:blood supply*; D009478:Neuropeptide Y / Q000032:analysis; D019001:Nitric Oxide Synthase / Q000032:analysis; D010477:Perfusion; D051381:Rats; D011916:Rats, Inbred F344; D013961:Thyroid Gland / Q000098:blood supply; D014660:Vasoactive Intestinal Peptide / Q000032:analysis
D009478:Neuropeptide Y; D014660:Vasoactive Intestinal Peptide; D005780:Gelatin; D019001:Nitric Oxide Synthase; D015740:Calcitonin Gene-Related Peptide