Reduced neuronal nitric oxide synthase (NOS1) antigen in sacral motor neurones in motor neurone disease

Immunocytochemistry and microdensitometry applied under standardised conditions were used to evaluate neuronal nitric oxide synthase (NOS 1) antigen in segmental motor neurones (MN) of six subjects without neurological disease, nine subjects with sporadic motor neurone disease (MND) and five with neurological disease unrelated to MND. No significant segmental differences in levels of NOS1 immunoreactivity occurred between the two control groups, and differences between cervical, thoracic and lumbar MN of the three subject groups were not significant. However, MND patients showed a significantly reduced level of NOS1 immunoreactivity in the Onuf's nucleus (ON); this is discussed in relation to neuroprotection and the relative sparing of ON in MND.