The neuroprotective role of the brain opioid system in stroke injury.

Novel neuroprotective therapies are desperately needed to improve neuronal recovery after ischemic stroke and extend the therapeutic window or offset some of the adverse effects of tissue-type plasminogen activator (tPA). These advances could provide a more effective and safe therapeutic regimen for patients with ischemic stroke. The opioid system has gained intense interest over the past few years and is currently being investigated as a viable target for the pharmacological treatment of stroke. In this review, we focus on different opioid receptors (ORs) and their distribution in the central nervous system (CNS), and the effect of ischemic stroke on their redistribution. We also discuss studies involving the use of the selective and nonselective and/or simultaneous targeting of ORs for neuroprotection during ischemic stroke.