The invention relates to Purine Derivatives; compositions comprising an effective amount of a Purine Derivative; and methods for reducing an animal's rate of metabolism, protecting an animal's heart against myocardial damage during cardioplegia; or for treating or preventing a cardiovascular disease, a neurological disorder, an ischemic condition, a reperfusion injury, obesity, a wasting disease, or diabetes, comprising administering an effective amount of a Purine Derivative to an animal in need thereof.