title: Vascular and neural mechanisms of ACh-mediated vasodilation in the forearm cutaneous microcirculation.
abstract: The relative contribution of endothelial vasodilating factors to acetylcholine (ACh)-mediated vasodilation in the forearm cutaneous microcirculation is unclear. The aims of this study were to investigate the contributions of prostanoids and cutaneous C fibers to basal cutaneous blood flow (CuBF) and ACh-mediated vasodilation. ACh was iontophoresed into the forearm, and cutaneous perfusion was measured by laser-Doppler flowmetry. To inhibit the production of prostanoids, four doses of acetylsalicylic acid (ASA; 81, 648, 972, and 1,944 mg) were administered orally. Cutaneous nerve fibers were blocked with topical anesthesia. Cyclooxygenase inhibition did not change basal CuBF or endothelium-mediated vasodilation to ACh. In contrast, ASA (972 and 1,944 mg) significantly reduced the C-fiber-mediated axon reflex in a dose-dependent fashion. Blockade of C-fiber function significantly reduced axon reflex-mediated vasodilation but did not affect basal CuBF or endothelium-dependent vasodilation. The findings suggest that prostanoids do not contribute significantly to basal CuBF or endothelium-dependent vasodilation in the forearm microcirculation. In contrast, prostanoids are mediators of the ACh-provoked axon reflex.
authors.affiliation: Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Berghoff
authors.forename: Madeera
authors.initials: M
authors.lastname: Kathpal
authors.forename: Sonja
authors.initials: S
authors.lastname: Kilo
authors.forename: Max J
authors.initials: MJ
authors.lastname: Hilz
authors.forename: Roy
authors.initials: R
authors.lastname: Freeman
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology / Q000502:physiology*; D000328:Adult; D001369:Axons / Q000502:physiology; D001808:Blood Vessels / Q000294:innervation; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D005260:Female; D005542:Forearm / Q000098:blood supply* / Q000294:innervation*; D006801:Humans; D007478:Iontophoresis; D008012:Lidocaine / Q000494:pharmacology; D000077442:Lidocaine, Prilocaine Drug Combination; D008297:Male; D008833:Microcirculation / Q000187:drug effects / Q000502:physiology; D011318:Prilocaine / Q000494:pharmacology; D012018:Reflex / Q000502:physiology; D012039:Regional Blood Flow / Q000187:drug effects; D012677:Sensation / Q000187:drug effects / Q000502:physiology; D012867:Skin / Q000098:blood supply*; D014664:Vasodilation / Q000502:physiology*; D014665:Vasodilator Agents / Q000008:administration & dosage* / Q000494:pharmacology
chemical_list: D000077442:Lidocaine, Prilocaine Drug Combination; D014665:Vasodilator Agents; D011318:Prilocaine; D008012:Lidocaine; D000109:Acetylcholine