PROBLEM TO BE SOLVED: To provide an adenosine receptor agonist having a preventive, a therapeutic or an improving effect on a cancer, an inflammatory symptom, an autoimmune disease, an ischemic reperfusion disturbance, an epilepsy, an epileptic shock, a nerve degeneration (including Alzheimer disease), a muscular fatigue or a muscular spasm.SOLUTION: Use of a specific 2-alkoxy adenosine substituted with an alkoxy group at a second position of a purine ring. Application of a compound shown by a formula (I) (wherein R represents 1-4C-alkoxy and X represents OH) and administered at an amount to give only a peak plasmaconcentration less than that of an EC50 value at pH 7.4 of the adenosine receptor after administration to the subject.【課題】癌、炎症、自己免疫疾患、虚血再灌流損傷、てんかん、敗血症、敗血症ショック、神経変性（アルツハイマー病を含む）、筋肉疲労または筋肉痙攣の予防、治療または改善効果を有するアデノシン受容体アゴニストの提供。【解決手段】プリン環の２位にアルコキシ基が置換した、特定な２－アルコキシアデノシンの使用。【選択図】なし
