Sex differences in XXXX -mediated vasoconstrictor tone in middle-aged and older adults.

@entity1 @entity712 @entity101 @entity2232 @entity11345 @entity301 @entity11344 @entity731 @entity65
The prevalence of @entity65 is lower in middle-aged and older @entity1 than @entity1 . Increased @entity2232 -mediated vasoconstriction has been linked to the etiology of a number of @entity65 , including @entity731 , @entity712 , and @entity101 . It is unknown whether a sex difference in @entity2232 -mediated vasoconstrictor tone exists in middle-aged and older adults. Therefore, we tested the hypothesis that middle-aged and older @entity1 would demonstrate greater ET-1-mediated vasoconstrictor tone than age-matched @entity1 . Forearm blood flow in response to intra-arterial infusions of @entity2232 , @entity11344 (a selective ET(A) receptor antagonist), and @entity11345 (a selective ET(B) receptor antagonist) was assessed by venous occlusion plethysmography in 21 @entity1 (age: 58 + or - 1 yr; body mass index: 26.0 + or - 1.0 kg/m(2)) and 25 @entity1 (age: 57 + or - 2 yr; body mass index: 26.8 + or - 0.7 kg/m(2)). In response to @entity11344 , the increase in forearm blood flow from baseline was significantly higher in the @entity1 than the @entity1 (24 + or - 5% vs. 9 + or - 5%; P < 0.05). In contrast, the increase in forearm blood flow in response to @entity11344 coinfused with @entity11345 was greater in the @entity1 than the @entity1 , such that the maximum vasodilation to dual endothelin receptor blockade was similar between @entity1 and @entity1 (approximately 25%). There was no difference in the vasoconstrictor response to ET-1 between the sexes. These results indicate that middle-aged and older @entity1 are under greater ET(A) receptor-mediated vasoconstrictor tone than age-matched @entity1 . Since the ET(A) receptor is the predominant receptor subtype in the coronary vasculature, this sex difference in vasoconstrictor tone may be a mechanism contributing to the sex difference in the prevalence of @entity301 in middle-aged and older adults.
