Impairment of endothelium-dependent responses of cerebral arterioles in chronic XXXX .

@entity6708 @entity64 @entity859 @entity101 @entity2806 @entity1242 @entity750 @entity35 @entity934
The goal of this study was to determine whether endothelium-dependent responses are impaired in the cerebral microcirculation of @entity64 -prone spontaneously @entity101 @entity35 (SHRSP). We measured diameters of cerebral arterioles using intravital microscopy in normotensive @entity35 (WKY) and SHRSP (6-8 mo old). Cerebral vasodilator responses to superfusion with @entity859 , which is an endothelium-independent agonist, were similar in WKY and SHRSP. In contrast, cerebral vasodilator responses to superfusion with endothelium-dependent agonists were profoundly impaired in SHRSP. @entity934 (10(-4) M) increased pial arteriolar diameter 23 +/- 2% (means +/- SE) in WKY and did not change arteriolar diameter in SHRSP (-2 +/- 3%, P less than 0.05 vs. WKY). @entity750 (10(-5) M) increased pial arteriolar diameter 23 +/- 1% in WKY and, in contrast, reduced diameter 11 +/- 1% in SHRSP (P less than 0.05 vs. WKY). @entity1242 and @entity934 produce vasodilatation by activation of @entity6708 ( @entity6708 ). @entity1242 was used to determine whether impaired responses of cerebral arterioles in SHRSP were related to altered @entity6708 activity. We found similar dilatation of cerebral arterioles in WKY and SHRSP in response to @entity1242 . Thus impaired endothelium-dependent dilatation in SHRSP is not related to alteration of @entity6708 activity. We speculate that impairment of cerebral vasodilator responses to endothelium-dependent agonists, including vasoactive substances released by platelets, may predispose SHRSP to @entity2806 .
