Effects of new nitric oxide synthase inhibitors on spontaneous locomotor activity

Abstract

Introduction. New nitric oxide synthase (NOS) inhibitors: 3-bromo-7-nitro- indazole (3-Br-7-NI), 1-(2-trifluoromethylphenyl) imidazole (TRIM), S-methyl-L-thiocitrulline (S-Me-TC) and 7-nitroindazole (7-NI) reduce spontaneous locomotor activity in mice. Material and methods. In order to elucidate central effects of NOS inhibitors on locomotor activity, the influence of 7-NI on electroencephalographic (EEG) power spectrum in rats was investigated. Results. 7-NI reduced the EEG power density in all frequency bands in rats, suggesting a depression of the central neuronal activity. The electrophysiologic power was most reduced in the range of 7-9 Hz of the rhythmic slow activity (theta rhythm), which is in accordance with decreased locomotor activity observed following administration of NOS inhibitors. Conclusion. The present results indicate that nitric oxide exerts an excitatory effect on central neuronal structures involved in regulation of locomotion. .