Inhibition of nitric oxide synthase reduces motoneuron death due to spinal root avulsion.

Our previous studies have shown that nitric oxide synthase (NOS) can be induced in motoneurons after spinal root avulsion lesion and the lesion-induced NOS is coincident with the death of the injured neurons. The present study examined whether the death of injured motoneurons can be prevented by inhibition of NOS. Nitroarginine, a specific inhibitor of NOS, was injected into adult rats which underwent spinal root avulsion. At a dose of 50 mg/kg/day, nitroarginine significantly inhibited the activity of lesion-induced NOS and significantly reduced the death of motoneurons due to spinal root avulsion. Results of the present study indicate that NO, produced by lesion-induced NOS, may be involved in and responsible for the neuronal death after traumatic injury.