Characterization of nitric oxide synthase in the cerebellum of the chicken

Nitric oxide synthase (NOS) activity in the chicken brain was examined, and higher activity was detected in the cerebellum. The NOS activity in the cerebellum was significantly inhibited in vitro by W-5, W-7 and trifluoperazine, and recovery of the activity was observed by the addition of calmodulin, suggesting that NOS is calmodulin dependent. Moreover, effects of EGTA and Ca2+ on NOS activity were also examined, and the results indicated that the enzyme is Ca2+ dependent. In addition, cofactors such as NADPH, flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) were required for the full expression of NOS. The results suggest that chicken cerebellum NOS has similar properties to those of mammalian neural NOS.