Regulation of the Strength of Adenosine Modulation in the Hippocampus by a Differential Distribution of the Density of A1 Receptors

Correlative studies examining: (1) the binding of [3H]cyclohexyladenosine to A1 adenosine receptor sites, and (2) the depressive action of adenosine on evoked activity, were performed in the hippocampal formation. A greater number of A1 sites was observed in the dorsal versus ventral aspect of the hippocampus, and a larger depression of evoked potentials by adenosine was obtained in the dorsal aspect. These observations suggest that a differential density of A1 receptors might control the magnitude of modulatory action by adenosine on hippocampal circuitry.