title: Lack of limb or sex differences in the cutaneous vascular responses to exogenous norepinephrine.
abstract: The cutaneous circulation is used to examine vascular adrenergic function in clinical populations; however, limited studies have examined whether there are regional limb and sex differences in microvascular adrenergic responsiveness. We hypothesized that cutaneous adrenergic responsiveness would be greater in the leg compared with the arm and that these regional limb differences would be blunted in young women (protocol 1). We further hypothesized that cutaneous vasoconstriction to exogenous norepinephrine (NE) during β-adrenergic receptor antagonism would be augmented in young women (protocol 2). In protocol 1, one microdialysis fiber was placed in the skin of the calf and the ventral forearm in 20 healthy young adults (11 men and 9 women). Laser-Doppler flowmetry was used to measure red blood cell flux in response to graded intradermal microdialysis infusions of NE (10(-12) to 10(-2) M). In protocol 2, three microdialysis fibers were placed in the forearm (6 men and 8 women) for the local perfusion of lactated Ringer (control), 5 mM yohimbine (α-adrenergic receptor antagonist), or 2 mM propranolol (β-adrenergic receptor antagonist) during concurrent infusions of NE (10(-12) to 10(-2) M). There were no limb or sex differences in cutaneous adrenergic responsiveness (logEC50) to exogenous NE. During α-adrenergic receptor blockade, women had greater exogenous NE-induced cutaneous vasodilation at the lowest doses of NE (10(-12) to 10(-10) M). Collectively, these data indicate that there are no limb or sex differences in cutaneous adrenergic responsiveness to exogenous NE; however, young women have a greater β-adrenergic receptor-mediated component of the vascular responsiveness to exogenous NE.
authors.affiliation: Noll Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania jlg52@psu.edu.
authors.forename: Jody L
authors.initials: JL
authors.lastname: Greaney
authors.affiliation: Noll Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania.
authors.forename: Anna E
authors.initials: AE
authors.lastname: Stanhewicz
authors.affiliation: Noll Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania.
authors.forename: W Larry
authors.initials: WL
authors.lastname: Kenney
authors.affiliation: Noll Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania.
authors.forename: Lacy M
authors.initials: LM
authors.lastname: Alexander
mesh_terms: D000279:Administration, Cutaneous; D000322:Adrenergic Agonists / Q000008:administration & dosage*; D018674:Adrenergic Antagonists / Q000008:administration & dosage; D000328:Adult; D001783:Blood Flow Velocity; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D017078:Laser-Doppler Flowmetry; D035002:Lower Extremity; D008297:Male; D008833:Microcirculation / Q000187:drug effects*; D017551:Microdialysis; D009638:Norepinephrine / Q000008:administration & dosage*; D012039:Regional Blood Flow; D012737:Sex Factors; D012867:Skin / Q000098:blood supply*; D034941:Upper Extremity; D014661:Vasoconstriction / Q000187:drug effects*; D014664:Vasodilation / Q000187:drug effects; D055815:Young Adult
chemical_list: D000322:Adrenergic Agonists; D018674:Adrenergic Antagonists; D009638:Norepinephrine
keywords: microdialysis; skin blood flow; vasoconstriction