Deprenyl Can Mediate Neuronal Protection Rather than Neuronal Rescue

Background and Objective: Deprenyl is a drug for the treatment of Parkinson’s disease, where the dopaminergic neurons are the target of this drug. Several reports also documented that deprenyl has an effect on the sensory and motor neurons. There are some reports about the mode of action of deprenyl on motoneurons as a neuroprotective agent, while others believe that deprenyl acts as a neurorescuer. Materials and Methods: In this experimental study, the axotomized spinal motoneurons in rat neonates were used to investigate the mode of action of deprenyl on motoneurons. Six groups of newborn rats (5 each) were used in this study. The first group was treated with 2.5 mg/kg of drug (for 21 days) one hour before surgical transection of the left sciatic side, the second treated at the time of surgery, and the third one treated one hour after surgery. The fourth, fifth, and sixth groups were given normal saline 1 hour before the surgery, at the time of surgery, and 1 hr after the surgery respectively. The animals were perfused and spinal cords were removed. The tissues were processed in paraffin and then sectioned. Tissues were stained with Cresyl violet. Total motoneuron count was done and the percentage of motoneuron reduction as well as motoneuron survival index was calculated. Results: The obtained data revealed that deprenyl in pre-treated group was more effective than in the other two modes of treatment. Conclusion: Taken together, deprenyl is more neuroprotective than neurorescuer of spinal motoneurons in rats.