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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

A key role for Na+/K+-ATPase in the endothelium-dependent oscillatory activity of mouse small mesenteric arteries

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Giachini, F. R. C. [1, 2] ; Carneiro, F. S. [1, 2] ; Lima, V. V. [1, 2] ; Carneiro, Z. N. [1] ; Brands, M. W. [1] ; Webb, R. C. [1] ; Tostes, R. C. [1, 2]
Total Authors: 7
[1] Med Coll Georgia, Dept Physiol, Augusta, GA 30912 - USA
[2] Univ Sao Paulo, Fac Med, Dept Farmacol, Sao Paulo - Brazil
Total Affiliations: 2
Document type: Journal article
Source: Brazilian Journal of Medical and Biological Research; v. 42, n. 11, p. 1058-1067, NOV 2009.
Web of Science Citations: 5

Oscillatory contractile activity is an inherent property of blood vessels. Various cellular mechanisms have been proposed to contribute to oscillatory activity. Mouse small mesenteric arteries display a unique low frequency contractile oscillatory activity (1 cycle every 10-12 min) upon phenylephrine stimulation. Our objective was to identify mechanisms involved in this peculiar oscillatory activity. First-order mesenteric arteries were mounted in tissue baths for isometric force measurement. The oscillatory activity was observed only in vessels with endothelium, but it was not blocked by L-NAME (100 mu M) or indomethacin (10 mu M), ruling out the participation of nitric oxide and prostacyclin, respectively, in this phenomenon. Oscillatory activity was not observed in vessels contracted with K(+) (90 mM) or after stimulation with phenylephrine plus 10 mM K(+). Ouabain (1 to 10 mu M, an Na(+)/K(+)-ATPase inhibitor), but not K(+) channel antagonists {[}tetraethylammonium (100 mu M, a nonselective K(+) channel blocker), Tram-34 (10 mu M, blocker of intermediate conductance K(+) channels) or UCL-1684 (0.1 mu M, a small conductance K(+) channel blocker)], inhibited the oscillatory activity. The contractile activity was also abolished when experiments were performed at 20 degrees C or in K(+)-free medium. Taken together, these results demonstrate that Na(+)/K(+)-ATPase is a potential source of these oscillations. The presence of alpha-1 and alpha-2 Na(+)/K(+)-ATPase isoforms was confirmed in murine mesenteric arteries by Western blot. Chronic infusion of mice with ouabain did not abolish oscillatory contraction, but up-regulated vascular Na(+)/K(+)-ATPase expression and increased blood pressure. Together, these observations suggest that the Na(+)/K(+) pump plays a major role in the oscillatory activity of murine small mesenteric arteries. (AU)

FAPESP's process: 06/01773-0 - RhoA/Rho-cinase signaling pathway in the vascular smooth muscle from mice with angiotensin II-induced hypertension: interaction with reactive oxygen species, interleukin-6 (IL-6) and JAK/STAT activation
Grantee:Rita de Cassia Aleixo Tostes Passaglia
Support type: Scholarships abroad - New Frontiers