摘要：Nitric oxide (NO) is an unconventional intercellular messenger in the brain synthesised from L-arginine by a family of enzimes called NO synthases (NOS). Recent studies have demonstrated that NO plays a role in the control of dopamine release in rat striatum. Presumably, NOS inhibitors could decrease locomotor activity by interfering with striatal dopamine. The aim of this study was to assess the effect of L-NOARG (90 mg/kg), a potent NOS inhibitor, on neuronal protein synthesis activity in striatum of mice after subchronic administration for 4 consecutive days. Neuronal protein synthesis activity was analyzed by quantifyng nuclear areas and number of silver-stained nucleolar organiser regions (Ag-NORs) per nucleus. These Ag-NORs may represent the transcriptional activity of the cell. The sections of striatum examined were silver stained according to the method described by Ploton et al. (1986). The results showed that mean number of Ag-NOR per nucleus significantly increased in the striatum of mice, as compared with the control group (p<0.05). These findings indicate the existence of an increase in transcriptional activity after L-NOARG treatment, suggesting that the neostriatal dopaminergic innervation quickly develops tolerance to the interruption of dopamine transmission by L-NOARG.
