Abstract
Mild thermal injury to the hindpaw induces tactile allodynia distal to the injury. The allodynia is blocked by non-NMDA, but not NMDA, antagonists. The calcium permeable subtype of non-NMDA receptors is blocked by Joro spider toxin (JSTX). We injected JSTX or saline intrathecally followed after 5 min, 6 or 24 h by thermal injury. Rats receiving saline had decreased mechanical thresholds. Rats receiving 3 microg JSTX 5 min or 6 h prior to burn showed no allodynia. JSTX had no prominent side effects at doses between 1 and 5 microg. JSTX (5 microg) had no effect on thermal threshold. These results are consistent with the hypothesis that spinal mechanisms leading to tactile allodynia in this injury model act via a calcium permeable AMPA linkage.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Burns / physiopathology
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Calcium / metabolism*
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Cell Membrane Permeability / drug effects
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Dose-Response Relationship, Drug
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Hair
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Hindlimb
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Hot Temperature
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Male
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Pain / drug therapy
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Pain / physiopathology
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Pain Threshold / drug effects*
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Physical Stimulation
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Rats
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Rats, Sprague-Dawley
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Reaction Time
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Receptors, AMPA / antagonists & inhibitors*
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Receptors, AMPA / metabolism*
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Receptors, N-Methyl-D-Aspartate / antagonists & inhibitors
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Receptors, N-Methyl-D-Aspartate / physiology
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Reflex / drug effects
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Reflex / physiology
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Respiration / drug effects
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Spider Venoms / pharmacology*
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Time Factors
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Touch / drug effects*
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Touch / physiology
Substances
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JSTX spider toxin
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Receptors, AMPA
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Receptors, N-Methyl-D-Aspartate
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Spider Venoms
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Calcium