Levodopa improves learning and memory ability on global cerebral ischemia-reperfusion injured rats in the Morris water maze test

Previous studies have shown that levodopa (L-dopa) for 1-7 days improved the consciousness level of certain patients who suffered from ischemia-reperfusion injury and were comatose for a long time period after cerebral resuscitation treatment. It also has an awakening effect on patients with disorders of consciousness. This study aimed to investigate whether L-dopa, which is used clinically to treat Parkinson's disease, might also ameliorate the behavior of rats following global cerebral ischemia-reperfusion injury. Fifty-six healthy adult male Sprague-Dawley rats were randomly divided into four groups: shamoperated, global cerebral ischemia mode, 25 mg/kg/d L-dopa intervention, and 50 mg/kg/d L-dopa intervention. The level of consciousness and modified neurological severity score (NSS) of the rats in each group were measured before reperfusion and 6, 24, and 72 h and 1-4 weeks after reperfusion. The Morris water maze test was used to assess behavior of rats 1 week after reperfusion and 2 weeks after reperfusion in each group. The results showed that after global cerebral ischemiareperfusion injury, neurological deficits of rats are severe, and space exploration capacity and learning and memory capacity are significantly decreased. L-dopa can shorten the duration of coma in rats following global cerebral ischemia-reperfusion injury and improve the symptoms of neurological deficits and advanced learning and memory. In the range of the selected doses, the relationship between L-dopa and improvement of the neurological behavior in rats was not dose-dependent. Dopamine may be useful for treating severe ischemia-reperfusion brain injury.