Spinal adenosine agonist reduces c-fos and astrocyte activation in dorsal horn of rats with adjuvant-induced arthritis.

Adjuvant-induced arthritis (AIA) is a useful animal model of rheumatoid arthritis (RA). We have previously shown that stimulation of spinal adenosine A1 receptors decreases peripheral signs of AIA. In this study we show that when the final dose of adenosine A1 agonist is given 1 h prior to sacrifice the number of c-Fos positive cells evoked by the AIA in both the superficial and deep dorsal horns decreases by about 50%. In saline-treated AIA animals the increase in c-Fos expression seen in laminae I-IV was accompanied by an increase in glial fibrillary acidic protein immunoreactivity, indicative of astrocyte activation. Astrocyte activation was only partially attenuated by adenosine A1 receptor agonist treatment. Copyright 2003 Published by Elsevier Science Ireland Ltd.