Document Detail

Central origin of secondary mechanical hyperalgesia.
MedLine Citation:
PMID:  12843313     Owner:  NLM     Status:  MEDLINE    
The contribution for the development of secondary mechanical hyperalgesia by peripheral mechanisms has not been fully elucidated. We have reevaluated the effects of local anesthetics on electrically evoked flare reaction and mechanical hyperalgesia in human skin. We applied 2% lidocaine via intradermal microdialysis fibers at a length of 10 cm for 110 min to the volar forearm to establish a narrow and stable "anesthetic strip." After 60 min of lidocaine perfusion, transdermal electrical stimulation (1 Hz, 50 mA) was applied at a distance of 1 cm from the microdialysis fibers for 30 min. The areas of allodynia and punctate hyperalgesia were marked at the end of the stimulation period. The flare reaction was assessed by laser Doppler scanner and infrared thermography. Total protein content of the dialysate collected at the stimulating electrode was measured photometrically. We found no increase in protein content during electrical stimulation. Flare area (12.4 +/- 2.3 vs. 3.5 +/- 1.2 cm2) and intensity (426 +/- 24 vs. 257 +/- 21 PU) were significantly reduced beyond the lidocaine strip. The mean temperature increase in the area beyond the lidocaine strip was significantly reduced (1.1 +/- 0.1 vs. 0.2 +/- 0.1 degrees C) and did not differ from control areas. In contrast, allodynia (7.4 +/- 0.7 and 8.6 +/- 0.9 cm) and punctate hyperalgesia (7.6 +/- 0.7 and 8.6 +/- 0.9 cm) developed symmetrically on both sides of the anesthetic strip. Allodynia subsided 4 min after the end of the electrical stimulation. We conclude that the development of allodynia and punctate hyperalgesia in human skin is centrally mediated, whereas the axon reflex vasodilation is of peripheral origin.
Monika Klede; Hermann O Handwerker; Martin Schmelz
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of neurophysiology     Volume:  90     ISSN:  0022-3077     ISO Abbreviation:  J. Neurophysiol.     Publication Date:  2003 Jul 
Date Detail:
Created Date:  2003-07-04     Completed Date:  2003-09-12     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0375404     Medline TA:  J Neurophysiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  353-9     Citation Subset:  IM    
Department of Physiology and Experimental Pathophysiology, University of Erlangen/Nürnberg, 91054 Erlangen, Germany.
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MeSH Terms
Anesthetics, Local / pharmacology*
Central Nervous System / physiopathology
Electric Stimulation
Hyperalgesia / physiopathology*
Laser-Doppler Flowmetry
Lidocaine / pharmacology*
Physical Stimulation
Proteins / analysis
Skin / drug effects,  physiopathology*
Reg. No./Substance:
0/Anesthetics, Local; 0/Proteins; 137-58-6/Lidocaine

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