5-Iodotubercidin is a potent inhibitor of the enzyme adenosine kinase. It has a recognized ability to enhance interstitial fluid levels of the cerebroprotective purine, adenosine, in the hypoxic brain, and an anticonvulsant action, which is thought to be a consequence of its ability to increase extracellular adenosine levels. 5-Iodotubercidin (1 mg/kg, i.p.) was therefore tested for its ability to reduce cerebral ischemic injury in a gerbil model. Unanesthetized gerbils were subjected to a 5 min period of bilateral carotid artery occlusion and then maintained in an environmental chamber at 30 degrees C for 5 hr to counteract the hypothermia-inducing action of 5-iodotubercidin. As estimated from the extent of the increases in locomotor activity and the magnitude of hippocampal CAI layer pyramidal cell loss, 5-iodotubercidin (1 mg/kg) failed to have a cerebroprotective effect against ischemic injury.