Glutamate-evoked release of adenosine and regulation of peripheral nociception

Neuroscience
N AumeerallyJana Sawynok

Abstract

Glutamate (which facilitates peripheral nociception) releases adenosine (which inhibits peripheral nociception via adenosine A(1) receptors) when injected locally into the rat hindpaw. The present study determined whether this locally released adenosine could modulate spontaneous pain behaviors produced by a local injection of 1.5% formalin, by determining the effect of 8-cyclopentyl-theophylline (CPT; selective adenosine A(1) receptor antagonist) on flinching produced by formalin/glutamate combinations. Experiments were performed following a prior conditioning injection of 2.5% formalin into the contralateral hindpaw 3-4 days earlier. CPT augmented flinching behaviors produced by 1.5% formalin/1 micromol glutamate, but had no effect on behaviors produced by formalin or glutamate alone. CPT also augmented flinches generated by formalin/alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and formalin/kainic acid, but not by formalin/N-methyl-D-aspartate (NMDA) combinations. The conditioning leads to a clearer expression of the peripheral inhibitory effect of adenosine (inhibitory effect of an inhibitor of adenosine kinase on flinching also was observed), rather than an increased release of adenosine (no enhanced rele...Continue Reading

References

Jul 3, 1998·European Journal of Pharmacology·J Sawynok
Apr 13, 1999·Trends in Neurosciences·M KoltzenburgS B McMahon
Nov 20, 2001·Current Opinion in Pharmacology·S M Carlton

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Citations

Mar 10, 2005·Experimental Neurology·Stephen B McMahonFabien Marchand
May 28, 2008·Neuron Glia Biology·Marc R SuterRu-Rong Ji
Jul 5, 2005·Nature Reviews. Neuroscience·Fabien MarchandStephen B McMahon
Jun 1, 2006·Expert Review of Neurotherapeutics·Robert J SchwartzmanJohn Grothusen
Jun 27, 2006·Pharmacology & Therapeutics·Nabih M Ramadan, Thomas M Buchanan
Sep 13, 2005·European Journal of Pharmacology·Jana SawynokFiona E Parkinson

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