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Whole-mount Immunohistochemical Analysis for Embryonic Limb Skin Vasculature: a Model System to Study Vascular Branching Morphogenesis in Embryo
Published on: May 20, 2011
Limb-specific differences in the skin vascular responsiveness to adrenergic agonists
1Laboratory for Human Physiology, School of Health Sciences, University of Occupational and Environmental Health (UOEH) 1-1 Iseigaoka, Yahatanishi-ku, 807-8555 Kitakyushu, Japan. yamazaki@health.uoeh-u.ac.jp
Leg skin shows greater vasoconstrictor response to adrenergic agonists than arm skin. This difference is primarily due to higher alpha-1 and alpha-2 adrenoceptor reactivity in the legs.
Area of Science:
- Physiology
- Dermatology
- Pharmacology
Background:
- Adrenergic agonists influence skin blood flow via vasoconstriction.
- Regional differences in vascular responsiveness are not fully understood.
Purpose of the Study:
- To compare leg versus arm cutaneous vascular conductance (CVC) responses to adrenergic agonists.
- To test if leg adrenergic vasoconstriction is greater than arm vasoconstriction.
Main Methods:
- Healthy volunteers received intradermal microdialysis of norepinephrine, phenylephrine, dexmedetomidine, and isoproterenol.
- Skin blood flow (SkBF) measured by laser-Doppler flowmetry.
- CVC calculated and compared between forearm and calf.
Main Results:
- Vasoconstrictor responses to norepinephrine were greater in the calf than forearm.
- Effective dose (ED50) for norepinephrine, phenylephrine, and dexmedetomidine was lower in the calf.
- Beta-agonist (isoproterenol) responses showed no significant regional difference.
Conclusions:
- Cutaneous vasoconstrictor responsiveness to norepinephrine is greater in human legs than arms.
- Higher alpha-1 and alpha-2 adrenoceptor reactivity in the legs explains this difference.
- Beta-adrenoceptor function plays a minor role in regional adrenergic vasoconstriction.
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