Investigative Ophthalmology & Visual Science, Vol 37, 2177-2184, Copyright © 1996 by Association for Research in Vision and Ophthalmology

ARTICLES AND REPORTS

Monkey central retinal artery is innervated by nitroxidergic vasodilator nerves

N Toda, M Toda, K Ayajiki and T Okamura
Department of Pharmacology, Shiga University of Medical Science, Ohtsu, Japan.

PURPOSE: To determine whether the monkey central retinal artery is innervated by vasodilator nerves and to analyze the mechanism underlying the neurogenic response. METHODS: Changes in isometric tension were recorded in helical strips of the arteries, which were stimulated by transmurally applied electrical pulses or nicotine. The presence of perivascular nerve fibers containing nitric oxide (NO) synthase immunoreactivity was determined histologically. RESULTS: Transmural electrical stimulation (5 Hz) and nicotine produced a relaxation of the arterial strips denuded of the endothelium, treated with prazosin, and contracted with prostaglandin F2 alpha. The response was not influenced by timolol, atropine, and indomethacin, but it was abolished by methylene blue and oxyhemoglobin. NG-nitro-L-arginine, a NO synthase inhibitor, abolished the neurogenic relaxation, and L- arginine restored the response. Antagonists of calcitonin gene-related peptide and vasoactive intestinal polypeptide in sufficient concentrations did not influence the response to nerve stimulation by nicotine. There were abundant nerve fibers and bundles containing NO synthase immunoreactivity in the adventitia. CONCLUSIONS: Monkey central retinal arteries are innervated by NO synthase-containing nerves that liberate NO possibly as a neurotransmitter on excitation to produce muscular relaxation.

This article has been cited by other articles:

				E. Mendrinos, I. K. Petropoulos, G. Mangioris, D. N. Papadopoulou, A. N. Stangos, and C. J. Pournaras Lactate-Induced Retinal Arteriolar Vasodilation Implicates Neuronal Nitric Oxide Synthesis in Minipigs Invest. Ophthalmol. Vis. Sci., November 1, 2008; 49(11): 5060 - 5066. [Abstract] [Full Text] [PDF]

				N. Toda and T. Okamura The Pharmacology of Nitric Oxide in the Peripheral Nervous System of Blood Vessels Pharmacol. Rev., June 1, 2003; 55(2): 271 - 324. [Abstract] [Full Text] [PDF]

				K. Ayajiki, T. Tanaka, T. Okamura, and N. Toda Evidence for nitroxidergic innervation in monkey ophthalmic arteries in vivo and in vitro Am J Physiol Heart Circ Physiol, October 1, 2000; 279(4): H2006 - H2012. [Abstract] [Full Text] [PDF]

				M. Toda, T. Okamura, K. Ayajiki, and N. Toda Neurogenic Vasoconstriction as Affected by Cholinergic and Nitroxidergic Nerves in Dog Ciliary and Ophthalmic Arteries Invest. Ophthalmol. Vis. Sci., July 1, 1999; 40(8): 1753 - 1760. [Abstract] [Full Text] [PDF]

				T. Okamura, K. Ayajiki, M. Uchiyama, M. Uehara, and N. Toda Neurogenic Vasodilatation of Canine Isolated Small Labial Arteries J. Pharmacol. Exp. Ther., March 1, 1999; 288(3): 1031 - 1036. [Abstract] [Full Text]

				P. A T Kelly, C. H Buckley, I. M Ritchie, and C. O'Brien Possible role for nitric oxide releasing nerves in the regulation of ocular blood flow in the rat Br. J. Ophthalmol., October 1, 1998; 82(10): 1199 - 1202. [Abstract] [Full Text]

				N. Toda, M. Toda, K. Ayajiki, and T. Okamura Cholinergic nerve function in monkey ciliary arteries innervated by nitroxidergic nerve Am J Physiol Heart Circ Physiol, May 1, 1998; 274(5): H1582 - H1589. [Abstract] [Full Text] [PDF]