Protective effects of dopamine D2/D3 receptor agonist piribedil on learning and memory of rats exposed to global cerebral ischemia-reperfusion.

Global cerebral ischemia-reperfusion (GCI/R) may occur after any of several clinical conditions such as cardiac arrest and anesthetic accident. Some dopamine receptor agonists possess neuroprotective effects. However, some of them may produce side effects during treatment. Piribedil, which is a dopamine D2/D3 receptor agonist, has fewer side effects and is well tolerated. This study investigated the effects of piribedil on learning and memory of rats with GCI/R according to modified neurological severity score (mNSS) scoring and Morris water maze test (MWM). Rats with GCI/R were treated with piribedil 25 or 50 mg/kg/d, and mNSS was performed at 6 h, 1 day, 3 days, and 1 and 2 weeks after injury. The MWM test was employed to evaluate learning and memory of rats at 1 and 2 weeks after injury. The results showed treatment with piribedil reduced the mNSS score and prolonged the time in the target quadrant compared with untreated rats although no obvious differences of the 25 and 50 mg/kg/d piribedil intervention groups were observed statistically. Piribedil is effective in improving the neurological function and learning and memory of rats after GCI/R.