Possible role for nitric oxide releasing nerves in the regulation of ocular blood flow in the rat

• Published in: British journal of ophthalmology Vol. 82; no. 10; pp. 1199 - 1202
• Main Authors: Kelly, Paul A T, Buckley, Christine H, Ritchie, Isobel M, O’Brien, Colm
• Format: Journal Article
• Language: English
• Published: BMA House, Tavistock Square, London, WC1H 9JR BMJ Publishing Group Ltd 01-10-1998; BMJ; BMJ Publishing Group LTD
• Subjects: 7-nitroindazole; Animals; Biological and medical sciences; Blood Flow Velocity; Blood pressure; Enzyme Inhibitors - pharmacology; Eye - blood supply; Eye and associated structures. Visual pathways and centers. Vision; Fundamental and applied biological sciences. Psychology; Indazoles - pharmacology; Male; neuronal nitric oxide synthase; Neurons - metabolism; NG-nitro-l-arginine methyl ester; NG-Nitroarginine Methyl Ester - pharmacology; Nitric oxide; Nitric Oxide - metabolism; Nitric Oxide - physiology; Nitric Oxide Synthase - antagonists & inhibitors; ocular blood flow; Original articles - Laboratory science; Rats; Rats, Sprague-Dawley; Rodents; Studies; Vertebrates: nervous system and sense organs; Rat; Rodentia; Blood flow; Eye; Visual system; Vertebrata; Regulation(control); Mammalia; Neuron; Animal; Nitric oxide; Physiology; Hemodynamics
• ISSN: 0007-1161; 1468-2079
• DOI: 10.1136/bjo.82.10.1199

AIM To investigate the role of nitrergic nerves in the regulation of ocular blood flow. METHODS Conscious, lightly restrained rats were treated with either the neuronal nitric oxide synthase inhibitor 7-nitroindazole (7-NI), or the non-selective inhibitor, NG-nitro-l-arginine methyl ester (L-NAME), and ocular blood flow was measured ex vivo from tissue samples, using the fully quantitative [14C]-iodoantipyrine technique. RESULTS In the peripheral circulation, L-NAME produced an increase in arterial blood pressure (+22%) while 7-NI had no effect. In contrast, both 7-NI and L-NAME produced significant decreases in ocular blood flow (−31% and −59% respectively). The ocular vascular resistance calculated from ocular blood flow and mean arterial blood pressure increased by 29% following 7-NI, but by 130% following L-NAME. CONCLUSIONS Nitric oxide releasing neurons may play an important contributory role in regulating ocular blood flow.