In summary, there is good evidence that adenosine is an endogenous neuroprotective agent. Probably several mechanisms can contribute to this effect and the relative importance of these mechanisms may depend on the type of ischaemia. There is also evidence that drugs that affect adenosine may be used therapeutically. An important caveat is that acute and long-term effects of adenosine receptor agonists and antagonists differ widely. This effect inversion suggests that drugs that affect adenosine receptors also induce important adaptive events in the central nervous system. Such adaptive effects may also be evident in the case of other agents, which emphasizes that the long-term usefulness of a therapeutic strategy cannot always be judged only from acute studies.