Abstract: AIM : To investigate sequential changes of nitirc oxide synthase expression in thepostembryonic development of cerebral cortex of the Chinese alligator.METHODS: Immunofluorescent technique was used to detect the temporal expression concerning its variation at location and content of NOS1 in the cerebral cortex of the Chinese alligator by postembryonic age of 0 mh(newly hatched), 3 mh, 6 mh, 12 mh, 24 mh and 120 mhs. RESULTS: Immunofluorescent experiments showed that NOS1-positive fluorescence reaction was not seen at the molecular layer of cerebral cortex from the alligator aged 0 mh, but seen at the other 3 layers. With increased ages, the layers of cerebral cortex gradually thickened, fluorescence reaction in the molecular layer appeared with enhanced positive reaction in the cell layer. By 120 mhs, NOS1-positive reaction amassed in the cell layer, which yellowish green and bright fluorescence increased and tailed out, while fluorescence of the outer and inner plexiform layers thickened. Yellowish green fluorescence were seen around vessels at all ages.Through analysis to its corresponding fluorescence density image, the result showed that the expression of various ages were discrepant (P<0.05) and gradually enhanced with increased ages. CONCLUSION: NOS1 is involved in the post-embryonic development of cerebral cortex of the Chinese alligator.

Key words: Chinese alligator, cerebral cortex, postembryonic development, nitirc oxide synthase, immunofluorescence