Microdialysis probes were implanted into the rabbit cerebral cortex and caudate nucleus followed by perfusion with Ringer solution at a flow rate of 3.0?l/min. Cerebral ischemia was induced by electrical stimulation of the unilateral superior cervical ganglion for 1h. Dialysate samples were analyzed by high performance liquid chromatography (HPLC). Following ischemia, extracelluar (EC) contents of adenosine (Ado) and its metabolites were significantly increased upto 6 ～ lOfold(Ado), 5 ～ 6fold(Inosine, Ino) and 2 ～ 3fold(Hypoxanthine, Hyp) in both the cerebral cortex and caudate nucleus(P