Mechanical allodynia in rats is blocked by a Ca2+ permeable AMPA receptor antagonist.
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.
Sorkin
L S
LS
Department of Anesthesiology, University of California San Diego, La Jolla 92103-0818, USA.
Yaksh
T L
TL
Doom
C M
CM
D000818:Animals; D002056:Burns / Q000503:physiopathology; D002118:Calcium / Q000378:metabolism*; D002463:Cell Membrane Permeability / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006197:Hair; D006614:Hindlimb; D006358:Hot Temperature; D008297:Male; D010146:Pain / Q000188:drug therapy / Q000503:physiopathology; D017288:Pain Threshold / Q000187:drug effects*; D010812:Physical Stimulation; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time; D018091:Receptors, AMPA / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000502:physiology; D012018:Reflex / Q000187:drug effects / Q000502:physiology; D012119:Respiration / Q000187:drug effects; D013111:Spider Venoms / Q000494:pharmacology*; D013997:Time Factors; D014110:Touch / Q000187:drug effects* / Q000502:physiology
C044936:JSTX spider toxin; D018091:Receptors, AMPA; D016194:Receptors, N-Methyl-D-Aspartate; D013111:Spider Venoms; D002118:Calcium