Nitric oxide synthase activity in brain tissues from llama fetuses submitted to hypoxemia

Galleguillos, M; Valenzuela, MA.; Riquelme R.; Sanhueza E.; Sánchez G; Figueroa JP; Llanos, AJ

Abstract

The fetal llama (Lama glama; a species adapted to live in chronic hypoxia in the highlands of the Andes) did not increase cerebral blood flow and reduce the brain oxygen uptake during hypoxemia. Although nitric oxide (NO) is a normal mediator in the regulation of vascular tone and synaptic transmission, NO overproduction by hypoxemia could produce neuronal damage. We hypothesized that nitric oxide synthase (NOS) activity is either maintained or reduced in the central nervous system of the llama fetuses submitted to chronic hypoxemia. Approximately 85% of the Ca2+-dependent NOS activity was soluble, at least 12% was associated with the mitochondrial fraction, and less than 5% remains associated with microsomes. To understand the role of NO in chronic hypoxemia, we determined the effect of 24-h hypoxemia on NOS activity in the central nervous system. No changes in activity or the subcellular distribution of NOS activity in brain tissues after hypoxemia were found. We proposed that the lack of changes in NOS activity in the llama under hypoxemia could be a cytoprotective mechanism inherent to the llama, against possible toxic effects of NO. © 2001 Elsevier Science Inc.

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Título según WOS: Nitric oxide synthase activity in brain tissues from llama fetuses submitted to hypoxemia
Título según SCOPUS: Nitric oxide synthase activity in brain tissues from llama fetuses submitted to hypoxemia
Título de la Revista: Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
Volumen: 129
Número: 02-mar
Editorial: Elsevier
Fecha de publicación: 2001
Página de inicio: 605
Página final: 614
Idioma: English
URL: http://linkinghub.elsevier.com/retrieve/pii/S1095643301002999
DOI:

10.1016/S1095-6433(01)00299-9

Notas: ISI, SCOPUS