Hypovolemic state: age-related influence of water restriction on cardiac nitric oxide synthase in rats.

AL FELLET, PR ARZA, M NUNEZ, CT ARRANZ, AND AM BALASZCZUK

EUROPEAN JOURNAL OF NUTRITION

DR DIETRICH STEINKOPFF VERLAG

Año: 2010

1436-6207

Abstract: Aim of study: We have assessed the influence of water restriction stress on the nitric oxide (NO) synthase in heart and aorta tissues in young 2-mo-old and middle-aged 12-mo-old rats. Methods:Animals were divided into: Control and deprived of water for 24 or 72 hours groups. We evaluated: Systolic blood pressure (SBP), biochemical parameters, nitrates and nitrites urinary excretion (UNOx), NADPH-diaphorase activity and protein levels of NOS in the right atria, left ventricle and thoracic aorta tissues. Results: Water restriction during 72 hours increased SBP (16%) in 2-mo-old rats but decreased it after 24 and 72 hours (9 and 15 %, respectively) in 12-mo-old rats. Atria, aorta endothelium and smooth muscle NOS activity increased (32, 63 and 88%, respectively) only after 72 hours of water restriction in 2-mo-old rats. It also increased not only after 72 hours but also after 24 hours in atria (27 and 18% respectively) and in ventricle (39 and 67%, respectively) in 12-mo-old rats. Meanwhile, in this group´s aorta smooth muscle the enzyme activity decreased (16% and 7%, respectively). A major difference seen between ages was the changes in UNOx excretion, which decreased in the younger in 24 and 72 hours (47 and 81 %, respectively) and increased in the middleaged rats (193 and 389 %, respectively).Water restriction did not change cardiovascular endothelial and neuronal NOS protein levels in any group. Conclusion: NO pathways could contribute to the development of age-related cardiovascular adaptation to volume depletion induced by water restriction.