Release of adenosine and other purines from hippocampal slices stimulated electrically or by hypoxia/hypoglycemia. Effect of chlormethiazole.

The ATP stores of rat hippocampal slices were labelled with [3H]-adenine. The efflux of endogenous and [3H]-purines was stimulated electrically or by combined hypoxia/hypoglycemia. The efflux of endogenous adenosine, inosine and hypoxanthine was also increased. Chlormethiazole (30-300 microM) decreased the [3H]-purine release evoked by hypoxia/hypoglycemia, but not that evoked by electrical field stimulation. The outflow of endogenous purines was not significantly altered by chlormethiazole, and there was no significant change in the relative proportions of endogenous purines released. Chlormethiazole (10-500 microM) did not block the uptake of adenosine by human erythrocytes. Chlormethiazole does not appear to have any primary effect on purine metabolism, but decreases the breakdown of ATP induced by a reduced supply of metabolites in hippocampal slices.