CATALEPSY INDUCED BY NITRIC-OXIDE SYNTHASE INHIBITORS

1. Previous study showed that N-G-nitro-L-arginine (L-NOARG), an inhib itor of nitric oxide synthase, induces catalepsy in a dose-dependent m anner in male albino Swiss mice. 2. The objective of the present work was to further investigate this effect, extending it to other NOS inhi bitors. 3. Results showed that L-NOARG (40-80 mg/kg IP), N-G-nitro L-a rginine methylester (L-NAME, 40-160 mg/kg IP) or N-G-monomethyl-L-argi nine (L-NMMA, 80 mg/kg IP) were able to induce catalepsy in mice. The effect of L-NOARG (40 mg/kg) was antagonized by pretreatment with L-ar ginine (300 mg/kg), but not by D arginine (300 mg/kg). The catalepsy i nducing effect of L-NOARG suffered rapid tolerance, showing a signific ant decrease after two days of chronic treatment (40 mg/kg IP, twice a day). 4. The results suggest that interference with the formation of nitric oxide induces significant motor effects in mice. (C) 1998 Elsev ier Science Inc.