Nitric oxide synthase inhibitor attenuates number of regenerating spinal motoneurons in adult rats

Neuronal survival and death-related effects of nitric oxide synthase are widely studied, yet its potential involvement in regeneration remains largely unexplored. In the present study, the regenerative role of nitric oxide synthase in injured motoneurons was investigated. A ventral root was avulsed and a piece of peripheral nerve was implanted into the spinal cord. Results showed that nitric oxide synthase inhibitor reduced the number of regenerating motoneurons to half compared with sham-operated control at 2 weeks and 4 weeks after injury, but the rate of axonal regeneration was not affected. Our study adds a new line of evidence that expression of nitric oxide synthase is beneficial to the axonal regeneration of the injured spinal motoneurons.