Document Detail


Is active sweating during heat acclimation required for improvements in peripheral sweat gland function?
MedLine Citation:
PMID:  19657101     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We investigated whether the eccrine sweat glands must actively produce sweat during heat acclimation if they are to adapt and increase their capacity to sweat. Eight volunteers received intradermal injections of BOTOX, to prevent neural stimulation and sweat production of the sweat glands during heat acclimation, and saline injections as a control in the contralateral forearm. Subjects performed 90 min of moderate-intensity exercise in the heat (35 degrees C, 40% relative humidity) on 10 consecutive days. Heat acclimation decreased end-exercise heart rate (156 +/- 22 vs. 138 +/- 17 beats/min; P = 0.0001) and rectal temperature (38.2 +/- 0.3 vs. 37.9 +/- 0.3 degrees C; P = 0.0003) and increased whole body sweat rate (0.70 +/- 0.29 vs. 1.06 +/- 0.50 l/h; P = 0.030). During heat acclimation, there was no measurable sweating in the BOTOX-treated forearm, but the control forearm sweat rate during exercise increased 40% over the 10 days (P = 0.040). Peripheral sweat gland function was assessed using pilocarpine iontophoresis before and after heat acclimation. Before heat acclimation, the pilocarpine-induced sweat rate of the control and BOTOX-injected forearms did not differ (0.65 +/- 0.20 vs. 0.66 +/- 0.22 mg x cm(-2) x min(-1)). However, following heat acclimation, the pilocarpine-induced sweat rate in the control arm increased 18% to 0.77 +/- 0.21 mg x cm(-2) x min(-1) (P = 0.021) but decreased 52% to 0.32 +/- 0.18 mg x cm(-2) x min(-1) (P < 0.001) in the BOTOX-treated arm. Using complete chemodenervation of the sweat glands, coupled with direct cholinergic stimulation via pilocarpine iontophoresis, we demonstrated that sweat glands must be active during heat acclimation if they are to adapt and increase their capacity to sweat.
Authors:
Michael J Buono; Travis R Numan; Ryan M Claros; Stephanie K Brodine; Fred W Kolkhorst
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2009-08-05
Journal Detail:
Title:  American journal of physiology. Regulatory, integrative and comparative physiology     Volume:  297     ISSN:  1522-1490     ISO Abbreviation:  Am. J. Physiol. Regul. Integr. Comp. Physiol.     Publication Date:  2009 Oct 
Date Detail:
Created Date:  2009-09-28     Completed Date:  2009-10-13     Revised Date:  2010-10-04    
Medline Journal Info:
Nlm Unique ID:  100901230     Medline TA:  Am J Physiol Regul Integr Comp Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  R1082-5     Citation Subset:  IM    
Affiliation:
Department of Biology, School of Exercise and Nutritional Sciences, San Diego State University, San Diego, California, USA. mbuono@mail.sdsu.edu
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MeSH Terms
Descriptor/Qualifier:
Acclimatization*
Adult
Body Temperature
Botulinum Toxin Type A / administration & dosage
Denervation / methods
Eccrine Glands / drug effects,  innervation,  physiology*
Exercise*
Female
Forearm
Heart Rate
Hot Temperature*
Humans
Injections, Intradermal
Iontophoresis
Male
Muscarinic Agonists / administration & dosage
Neuromuscular Agents / administration & dosage
Pilocarpine / administration & dosage
Sweating* / drug effects
Time Factors
Young Adult
Grant Support
ID/Acronym/Agency:
3S06GM64105-01S1/GM/NIGMS NIH HHS
Chemical
Reg. No./Substance:
0/Botulinum Toxin Type A; 0/Muscarinic Agonists; 0/Neuromuscular Agents; 92-13-7/Pilocarpine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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