Limb-specific differences in the skin vascular responsiveness to adrenergic agonists

作者：Yamazaki Fumio^*; Yuge Nagisa

来源：Journal of Applied Physiology, 2011, 111(1): 170-176.

DOI：10.1152/japplphysiol.00068.2011

• skin blood flow
• exogenous norepinephrine
• alpha-adrenergic receptor
• beta-adrenergic receptor
• microdialysis

Yamazaki F, Yuge N. Limb-specific differences in the skin vascular responsiveness to adrenergic agonists. J Appl Physiol 111: 170-176, 2011. First published April 28, 2011; doi:10.1152/japplphysiol.00068.2011.-In this study, to test the hypothesis that adrenergic vasoconstrictor responses of the legs are greater compared with the arms in human skin, cutaneous vascular conductance (CVC) in the forearm and calf were compared during the infusion of adrenergic agonists in healthy young volunteers. Under normothermic conditions, norepinephrine (NE, alpha- and beta-agonist, 1 x 10 (8) to 1 x 10 (2) M), phenylephrine (PHE, alpha(1)-agonist, 1 x 10 (8) to 1 x 10 (2) M), dexmedetomidine (DEX, alpha(2)-agonist, 1 x 10(-9) to 1 x 10(-4) M), and isoproterenol (ISO, beta-agonist, 1 x 10(-8) to 1 x 10(-3) M) were administered by intradermal microdialysis. Skin blood flow (SkBF) was measured by laser-Doppler flowmetry, and the local temperature at SkBF-measuring sites was maintained at 34 degrees C throughout the experiments. CVC was calculated as the ratio of SkBF to blood pressure and expressed relative to the baseline value before drug infusion. The dose of NE at the onset of vasoconstriction and the effective dose (ED(50)) resulting in 50% of the maximal vasoconstrictor response for NE were lower (P < 0.001) in the calf than forearm. The ED(50) for PHE and DEX was also lower (P < 0.05) in the calf than forearm. Increases in CVC in response to ISO were potentially smaller in the calf, but the statistical differences in the responses were dependent on the expressions of CVC. These findings suggest that the cutaneous vasoconstrictor responsiveness to exogenous NE is greater in the legs than in the arms due to a higher alpha(1)- and alpha(2)-adrenoceptor reactivity, while the beta-adrenoceptor function plays a minor role in regional differences in adrenergic vasoconstriction in normothermic humans.

• 出版日期2011-7