Different vasodilator responses of XXXX arms and legs.

@entity1 @entity1009 @entity1854 @entity1503 @entity4757 @entity934
Forearm vascular responses to intra-arterial infusions of endothelium-dependent and -independent vasodilators have been thoroughly characterized in @entity1 . While the forearm is a well-established experimental model for studying @entity1 vascular function, it is of limited consequence to systemic cardiovascular control owing to its small muscle mass and blood flow requirements. In the present study we determined whether these responses could be generalized to the leg. Based upon blood pressure differences between the leg and arm during upright posture, we hypothesized that the responsiveness to endothelium-dependent vasodilators would be greater in the forearm than the leg. @entity1503 (Q, ultrasound Doppler) at rest and during intra-arterial infusions of endothelium-dependent ( @entity934 and @entity4757 ) and -independent ( @entity1854 ) vasodilators were measured in eight healthy @entity1 (22-27 years old). Resting blood flows in the forearm before infusion of @entity934 , @entity4757 or @entity1854 were 25 +/- 4, 30 +/- 7 and 29 +/- 5 ml @entity1009 ), respectively, and in the leg were 370 +/- 32, 409 +/- 62 and 330 +/- 30 ml @entity1009 ), respectively. At the highest infusion rate of @entity934 (16 microg (100 ml tissue)(-1) @entity1009 )) there was a greater (P < 0.05) increase in Q to the forearm (1864 +/- 476%) than to the leg (569 +/- 86%). Similarly, at the highest infusion rate of @entity4757 (125 pg (100 ml tissue)(-1) @entity1009 )) there was a greater (P < 0.05) increase in Q to the forearm (911 +/- 286%) than to the leg (243 +/- 58%). The responses to @entity1854 (1 microg (100 ml tissue)(-1) @entity1009 )) were also greater (P < 0.05) in the forearm (925 +/- 164%) than in the leg (326 +/- 65%). These data indicate that vascular responses to both endothelium-dependent and -independent vasodilator agents are blunted in the leg compared to the forearm.
