title: Effects of atropine and L-NAME on cutaneous blood flow during body heating in humans.
abstract: We sought to investigate further the roles of sweating, ACh spillover, and nitric oxide (NO) in the neurally mediated cutaneous vasodilation during body heating in humans. Six subjects were heated with a water-perfused suit while cutaneous blood flow was measured with a laser-Doppler flowmeter. After a rise in core temperature (1. 0 +/- 0.1 degrees C) and the establishment of cutaneous vasodilation, atropine and subsequently the NO synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) were given to the forearm via a brachial artery catheter. After atropine infusion, cutaneous vascular conductance (CVC) remained constant in five of six subjects, whereas L-NAME administration blunted the rise in CVC in three of six subjects. A subsequent set of studies using intradermal microdialysis probes to selectively deliver drugs into forearm skin confirmed that atropine did not affect CVC. However, perfusion of L-NAME resulted in a significant decrease in CVC (37 +/- 4%, P < 0.05). The results indicate that neither sweating nor NO release via muscarinic receptor activation is essential to sustain cutaneous dilation during heating in humans.
authors.affiliation: Department of Physiology and Biophysics, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA.
authors.forename: S
authors.initials: S
authors.lastname: Shastry
authors.forename: C T
authors.initials: CT
authors.lastname: Minson
authors.forename: S A
authors.initials: SA
authors.lastname: Wilson
authors.forename: N M
authors.initials: NM
authors.lastname: Dietz
authors.forename: M J
authors.initials: MJ
authors.lastname: Joyner
mesh_terms: D000328:Adult; D001285:Atropine / Q000494:pharmacology*; D001831:Body Temperature / Q000502:physiology*; D001916:Brachial Artery / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007260:Infusion Pumps; D008297:Male; D017551:Microdialysis; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D010276:Parasympatholytics / Q000494:pharmacology; D012039:Regional Blood Flow / Q000187:drug effects; D012867:Skin / Q000098:blood supply*; D012879:Skin Physiological Phenomena / Q000187:drug effects; D013546:Sweating / Q000502:physiology; D013997:Time Factors; D014655:Vascular Resistance / Q000187:drug effects
chemical_list: D004791:Enzyme Inhibitors; D010276:Parasympatholytics; D001285:Atropine; D019331:NG-Nitroarginine Methyl Ester