Role of endogenous adenosine in the expression of opiate withdrawal in rats

Samples of extracellular fluid from striatum and nucleus accumbens of anaes thetised rats undergoing opiate withdrawal were collected using microdialys is and then analysed for adenosine and its metabolites using high performan ce liquid chromatography (HPLC) and ultraviolet (UV) detection. Although th e amount of adenosine present in the dialysate from either brain region was below the limit of detection by 90 min after probe placement, the metaboli tes could still be detected. Samples of dialysates collected from the nucle us accumbens contained significantly higher concentrations of hypoxanthine and inosine following naloxone challenge. The data are compatible with the hypothesis that endogenous adenosine might be involved in the expression of the opiate abstinence syndrome. (C) 1999 Elsevier Science B.V. All rights reserved.