Doxazosin and soluble guanylate cyclase in a rat model of hypertension]

Background. Although different studies have evaluated the ability of endothelial cells to produce NO in the setting of the endothelial dysfunction associated with hypertension, less it is known about the soluble guanylate cyclase system. Aim. To analyze the level of expression of sGC in the vascular wall in Stroke-prone spontaneously hypertensive rats (SHRSP). Moreover, the effect of treatment with an alpha (1) adrenergic antagonist, doxazosin, on sGC expression was also evaluated. Methods. The study was performed in 24 untreated 20-week-old SPSHR and 12 SPSHR treated orally with doxazosin (10 mg/Kg bw/day; for 15 days). A group of normotensive Wistar-Kyoto (WKY) rats were used as controls (n = 12). Results. Isolated aortic segments from SHRSP showed impaired response to SNP. Doxazosin treatment prevented impaired vasodilatory response to SNIP. Expression of the beta (1) sGC in the vascular wall of SHRSP determined by Western blot and immunohistochemistry was markedly reduced with respect to that of WKY. Doxazosin treatment increased of beta (1) sGC expression in treated SHRSP particularly at the medium level with respect to that of untreated SHRSP. Conclusion. SHRSP showed reduced expression of beta (1) sGC in the vascular wall and an impaired vasoclilator response to SNP which improved with doxazosin treatment. These results suggest the role the sGC system may play in the global treatment of endothelial dysfunction.