[Expressional change of nitric oxide synthases in dorsal root ganglia of cats after selective dorsal rhizotomy].

OBJECTIVE: To examine the expressional change of nitric oxide synthase (NOS) in the injured dorsal root ganglia (DRG) and the ipsilateral adjacent uninjured DRG after selective dorsal rhizotomy. METHODS: Immunochemical ABC method was used to detect the distribution of immunoreaction complex of NOS isoforms--nNOS and eNOS, and quantitative analysis was conducted to get the number of nNOS-immunoreactivity (nNOS-IR) neurons in normal DRG, dorsal rhizotomized DRG and spared DRG from adult cats on the 6th day after operation. This operating model was made by rhizotomizing unilateral L1-L5 dorsal roots and leaving L6 as a spared root. RESULTS: nNOS-immunoreactants were mainly distributed in the small-sized neurons in the DRG of cat. The percentage of nNOS-expressing small-sized neurons increased in the deafferentated L5 DRG (29.74%) when compared with the contralateral DRG (19.35%), and it also increased in the spared DRG (24.22%), compared with the contralateral DRG (18.61%). eNOS-IR was not observed in the DRG of adult cats. CONCLUSION: nNOS/NO up-regulated in DRG neurons is involved in a wide variety of biological functions under physiological and lesion-induced pathophysiological conditions in nerve system.