Adenosine receptor agonists inhibit inositol phosphate accumulation in rat striatal slices

The accumulation of inositol-1-phosphate in rat striatal slices was inhibited by the adenosine analogues 5'-N-ethylcarboxamide-adenosine and N6-phenylisopropyladenosine. Maximal inhibition (approximately 20%) was achieved by micromolar concentrations of either compound. Both basal and stimulated values could be inhibited, and the inhibition was reversible by the adenosine receptor antagonist 8-phenyltheophylline (10 microM). The results suggest that adenosine may exert a tonic inhibitory influence on inositol phospholipid-derived second messenger production in the striatum in vivo.