Abstract
Unlike the mammals, fish optic nerve can regenerate their axons after axotomy. There is much knowledge about axon guidance molecules revealed by classical biochemical techniques. The previous studies demonstrated that nitric oxide synthase (NOS) recognized as NADPH-diaphorase and growth associated protein-43 (GAP-43) were upregulated after fish optic nerve injury by histochemical and two-dimmensional electrophoresis. To further investigate molecular mechanism of neural type of NOS and GAP-43 in the goldfish retina during optic nerve regeneration. We isolated cDNA fragments for nNOS and GAP-43 with probes of PCR products amplified by primers constructed from zebrafish and goldfish sequences, respectively. We got 490 bp fragment of nNOS cDNA and 639 bp fragment of GAP-43 cDNA. By using these cDNA clones, Northern blot hybridization was done in the goldfish retinal samples following optic nerve injury. The level of GAP-43 mRNA significantly increased about 2-fold 1 week after treatment and then gradually declined by 30 days after optic nerve injury. We are now in progress to investigate the localization of nNOS and GAP-43 mRNA in the fish retina with in situ hybridization and to further investigate the functional role of these molecules on neurite outgrowth with in vitro culture system. [Jpn J Physiol 54 Suppl:S213 (2004)]
