title: Effect of skin temperature on cutaneous vasodilator response to the β-adrenergic agonist isoproterenol.
abstract: The vascular response to local skin cooling is dependent in part on a cold-induced translocation of α2C-receptors and an increased α-adrenoreceptor function. To discover whether β-adrenergic function might contribute, we examined whether β-receptor sensitivity to the β-agonist isoproterenol was affected by local skin temperature. In seven healthy volunteers, skin blood flow was measured from the forearm by laser-Doppler flowmetry and blood pressure was measured by finger photoplethysmography. Data were expressed as cutaneous vascular conductance (CVC; laser-Doppler flux/mean arterial blood pressure). Pharmacological agents were administered via intradermal microdialysis. We prepared four skin sites: one site was maintained at a thermoneutral temperature of 34°C (32 ± 10%CVCmax) one site was heated to 39°C (38 ± 11%CVCmax); and two sites were cooled, one to 29°C (22 ± 7%CVCmax) and the other 24°C (16 ± 4%CVCmax). After 20 min at these temperatures to allow stabilization of skin blood flow, isoproterenol was perfused in concentrations of 10, 30, 100, and 300 μM. Each concentration was perfused for 15 min. Relative to the CVC responses to isoproterenol at the thermoneutral skin temperature (34°C) (+21 ± 10%max), low skin temperatures reduced (at 29°C) (+17 ± 6%max) or abolished (at 24°C) (+1 ± 5%max) the vasodilator response, and warm (39°C) skin temperatures enhanced the vasodilator response (+40 ± 9%max) to isoproterenol. These data indicate that β-adrenergic function was influenced by local skin temperature. This finding raises the possibility that a part of the vasoconstrictor response to direct skin cooling could include reduced background β-receptor mediated vasodilation.
authors.affiliation: Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada; Department of Physiology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas; and.
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Hodges
authors.affiliation: Department of Physiology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas; and Department of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, Texas dkellogg@uthscsa.edu.
authors.forename: Dean L
authors.initials: DL
authors.lastname: Kellogg
authors.affiliation: Department of Physiology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas; and.
authors.forename: John M
authors.initials: JM
authors.lastname: Johnson
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000328:Adult; D001783:Blood Flow Velocity / Q000187:drug effects / Q000502:physiology*; D003080:Cold Temperature; D005260:Female; D006801:Humans; D007036:Hypothermia, Induced; D007545:Isoproterenol / Q000494:pharmacology*; D008297:Male; D012879:Skin Physiological Phenomena / Q000187:drug effects*; D012881:Skin Temperature / Q000187:drug effects / Q000502:physiology*; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*
chemical_list: D000318:Adrenergic beta-Agonists; D007545:Isoproterenol
keywords: local cooling; local heating; noradrenaline; β-adrenergic receptors