An adenosine agonist inhibits and a cyclic AMP analogue enhances the release of glutamate but not GABA from slices of rat dentate gyrus.

The adenosine agonist 2-chloroadenosine inhibited the K+-induced release of endogenously synthesized [3H]glutamate but not [3H]GABA from slices of rat dentate gyrus. In contrast, the K+-stimulated release of [3H]glutamate was augmented by the adenosine antagonist theophylline and was further enhanced by the cyclic AMP analogue 8-bromo-cyclic AMP in the presence of theophylline.