Inducible nitric oxide synthase increases in regenerating rat ganglia.

Nitric oxide synthase (NOS) exists in several isoforms. In this study we used immunocytochemistry to investigate one isoform, inducible NOS (iNOS), in the nodose ganglia (NG) and in the superior cervical ganglia (SCG) of the rat. iNOS was present in many neurones of the NG, while no iNOS-positive cells could be observed in the SCG. At 24 and 48 h following a crush lesion to the vagus nerve, expression of iNOS-immunoreactivity had increased in the NG. iNOS-immunoreactivity increased in both the NG and SCG of ganglia cultured for 24 and 48 h. The results show that an increase in iNOS-immunoreactivity accompanies regenerative processes in two peripheral ganglia, suggesting that nitric oxide, the product of iNOS activity, could be involved in nerve regeneration.