Evidence for the presence of excitatory A2 adenosine receptors in the rat hippocampus.

The A2 adenosine receptor agonist, CGS 21680 in nanomolar concentrations, reversibly increased in a concentration-dependent manner the amplitude of orthodromically-evoked population spikes recorded from the CA1 pyramidal cell layer of rat hippocampal slices. The adenosine receptor antagonist, 3,7-dimethyl-l-propargylxanthine (DMPX, 10 microM), which has selectivity for A2 adenosine receptors, prevented this excitatory effect of CGS 21680. These results suggest that A2 adenosine receptors are present in the rat hippocampus and that activation of these receptors enhance hippocampal excitability.