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Titolo:
Major role for neuronal NO synthase in curtailing choroidal blood flow autoregulation in newborn pig
Autore:
Hardy, P; Lamireau, D; Hou, X; Dumont, I; Abran, D; Nuyt, AM; Varma, DR; Chemtob, S;
Indirizzi:
Hop St Justine, Res Ctr, Dept Pediat, Montreal, PQ H3T 1C5, Canada Hop St Justine Montreal PQ Canada H3T 1C5 t, Montreal, PQ H3T 1C5, Canada Hop St Justine, Res Ctr, Dept Ophthalmol, Montreal, PQ H3T 1C5, Canada HopSt Justine Montreal PQ Canada H3T 1C5 l, Montreal, PQ H3T 1C5, Canada Hop St Justine, Res Ctr, Dept Pharmacol, Montreal, PQ H3T 1C5, Canada Hop St Justine Montreal PQ Canada H3T 1C5 l, Montreal, PQ H3T 1C5, Canada McGill Univ, Dept Pharmacol & Therapeut, Montreal, PQ H3G 1Y6, Canada McGill Univ Montreal PQ Canada H3G 1Y6 peut, Montreal, PQ H3G 1Y6, Canada
Titolo Testata:
JOURNAL OF APPLIED PHYSIOLOGY
fascicolo: 4, volume: 91, anno: 2001,
pagine: 1655 - 1662
SICI:
8750-7587(200110)91:4<1655:MRFNNS>2.0.ZU;2-G
Fonte:
ISI
Lingua:
ENG
Soggetto:
NITRIC-OXIDE SYNTHASE; PERFUSION-PRESSURE; EDINGER-WESTPHAL; 7-NITRO INDAZOLE; CILIARY ARTERIES; RAT; PROSTAGLANDINS; NUCLEUS; HYPERTENSION; VASODILATION;
Keywords:
ocular blood flow; retina; choroid; nitric oxide;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
52
Recensione:
Indirizzi per estratti:
Indirizzo: Chemtob, S Hop St Justine, Res Ctr, Dept Pediat, 3175 Cote St Catherine, Montreal, PQH3T 1C5, Canada Hop St Justine 3175 Cote St Catherine Montreal PQ Canada H3T 1C5
Citazione:
P. Hardy et al., "Major role for neuronal NO synthase in curtailing choroidal blood flow autoregulation in newborn pig", J APP PHYSL, 91(4), 2001, pp. 1655-1662

Abstract

We examined whether nitric oxide (NO) generated from neuronal NO synthase (nNOS) contributes to the reduced ability of the newborn to autoregulate retinal blood flow (RBF) and choroidal blood flow (ChBF) during acute rises in perfusion pressure. In newborn pigs (1-2 days old), RBF (measured by microsphere) is autoregulated over a narrow range of perfusion pressure, whereas ChBF is not autoregulated. N-G-nitro-L-arginine methyl ester (L-NAME) or specific nNOS inhibitors 7-nitroindazole, 3-bromo-7-nitroindazole, and 1-(2-trifluoromethyl-phenyl)imidazole as well as ganglionic blocker hexamethonium, unveiled a ChBF autoregulation as observed in juvenile (4- to 6-wk old)animals, whereas autoregulation of RBF in the newborn was only enhanced byL-NAME. All NOS inhibitors and hexamethonium prevented the hypertension-induced increase, in NO mediator cGMP in the choroid. nNOS mRNA expression and activity were three- to fourfold higher in the choroid of newborn pigs than in tissues of juvenile pigs. It is concluded that increased production of NO from nNOS curtails ChBF autoregulation in the newborn and suggests a role for the autonomic nervous system in this important hemodynamic function, whereas, for RBF autoregulation, endothelial NOS seems to exert a more important contribution in limiting autoregulation.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/04/20 alle ore 08:54:14