Serotonin modulation of catalepsy induced by N-G-nitro-L-arginine in mice

N-G-Nitro-L-arginine (L-NOARG), an inhibitor of nitric oxide synthase, indu ces catalepsy in mice. The objective of the present work was to investigate if serotonergic drugs are able to modulate this effect. Results showed tha t the cataleptogenic effect of L-NOARG (40 mg/kg) in male albino-Swiss mice was enhanced by pre-treatment with (+)-N-tert-butyl-3-(4-[2-methoxyphenyl] piperazin-1-yl)-2- phenylprapanamide ((+)-WAY-100135, 5 or 10 mg/kg), a 5-H T1A-selective receptor antagonist, and by ketanserin (5 or 10 mg/kg), a 5-H T2A receptor and alpha(1)-adrenoceptor antagonist. Prazosin (3 or 5 mg/kg), an alpha(1)-adrenoceptor antagonist, and endo-N-(8-methyl-8-azabicyclo[3.2 . 1]oct-3yl)-2,3-dihydro-3,3-dimethyl-indole-1-carobxamide HCl (BRL-46470A, 0.05 or 0.5 mg/kg), a 5-HT3 receptor antagonist, did not interfere with L- NOARG-induced catalepsy. Ritanserin (3 or 10 mg/kg), a 5-HT2A and 5-HT2C re ceptor antagonist, tended to enhance the effect of L-NOARG. These results c onfirm that interference with the formation of nitric oxide induces catalep sy in mice, and suggest that this effect is modulated by 5-HT1A and 5-HT2A receptors. (C) 1999 Elsevier Science B.V. All rights reserved.