1. The adenosine A(1) receptor enhancer, PD 81,723, was tested for its neuroprotective activity in a Mongolian gerbil model of forebrain ischemia/reperfusion cerebral ischemia. 2. Gerbils were injected with PD 81,723 (1, 10 and 125 mg/kg i.p.) 20 min before a 5-min episode of forebrain ischemia. The extent of ischemic injury was assessed by monitoring the increases in locomotor activity and from the degree of damage to the CA1 hippocampal pyramidal cell layer after 5 days of recovery. 3. By both criteria, PD 81,723, at all three dose levels, failed to protect against ischemia/reperfusion evoked cerebral injury.