FIGURE 1. Infarct Volumes of Mice Subjected to Transient Cerebral Ischemia
Melatonin led to a decrease in infarct size in treated animals. *Significantly different from vehicle-treated control animals (p≤0.05).
To the Editor: It is widely known that occurrence of poststroke mood disorders, especially depression, is one of the most frequent complications of stroke.1 It affects approximately 20%—40% of all patients and the definitive treatment of this clinical picture includes various antidepressant agents.1
The evidence about the antidepressant-like activity of melatonin and melatonin agonists is rapidly increasing.2—7 However melatonin is also an important agent in sleep disturbances, which are shown to be associated with stroke.8 In light of these findings we wanted to evaluate whether this novel antidepressant agent also has neuroprotective effect on cerebral ischemia.
To examine this matter we evaluated the neuroprotective effect of melatonin in a relevant model for stroke in humans. Thus we administered the indole prophylactically for 4 weeks before the middle cerebral artery thread occlusions and evaluated the effects of melatonin treatment on ischemic brain injury 24 hours after reperfusion. Reproducibility of cerebral ischemia was controlled by Laser Doppler Flowmetry, and the neuroprotection was evaluated by infarct volume measurements (Figure 1
). Melatonin significantly reduced the infarct size (Figure 1
) (mean 1.12±0.5 mm3 compared to 2.62±0.5 mm3) when given prophylactically (p<0.05). This study was interesting with regard to poststroke depression by which a mood stabilizer with neuroprotective property would be preferable. Additionally, this finding supports that melatonin may be a suitable agent for patients with stroke and sleep disturbances, not only with its inhibiting effect on ischemic neuronal injury, but also with its improving effect on sleep disturbances. This can in turn provide additional support for the restorative process after brain injury.
However, further experiments to evaluate the long-term clinical applicability of such neuroprotective effects of melatonin in poststroke depression patients with MRI and spectroscopy studies would be the logical future steps to be taken in the field of psychiatric research.