Date of Award


Degree Type


Degree Name

Master of Science




Dr. Kevin ShoemakerMyogenic, Alpha-adrenergic, Norepinephrine, Phentolamine, Windkessel, Doppler ultrasound


We tested the hypotheses that forearm vascular compliance (C) but not resistance (R) would be influenced by myogenic stimuli, and changing (A) forearm transmural pressure (TP) would influence the effect of a-adrenergic input on C and R. Continuous forearm blood flow was measured during Norepinephrine (NE; a-agonist) and during concurrent NE and Phentolamine (PH; a-antagonist) infusion with the arm above and below heart level (n=10). C was inversely related to TP (p<0.05). NE decreased C and increased R (p<0.05). PH abolished these responses. The effect of NE on AC was greater with the arm above versus below heart level (p<0.05), while AR was only observed with the arm below the heart (p<0.05). Conclusions: Myogenic changes affect forearm vascular C

independent of changes in R. Alpha -adrenergic activation reduces C and increases R. Furthermore, with NE, AC requires a high starting value of C, while AR occurs under high TP



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