L-NAME precipitates catatonia during ethanol withdrawal in rats

Abstract

The effect of N G-nitro- l-arginine methyl ester ( l-NAME), a non-specific inhibitor of nitric oxide (NO) synthase, on catatonia in ethanol dependent rats was investigated. Ethanol was given to rats by a modified liquid diet. An isocaloric liquid diet without ethanol was also given to control rats. l-NAME (50, 100 and 200 mg/kg) and saline were injected intraperitoneally to ethanol-dependent rats 30 min before ethanol withdrawal. Then, catatonia was evaluated by vertical wire test at the 30th min, 2nd, 4th and 6th h of ethanol withdrawal. The injections were repeated 30 min before the observation of 6 h. Locomotor activity was also recorded for 5 min in the same observation intervals. l-NAME (200 mg/kg) or saline were also injected to ethanol non-dependent control rats. l-NAME (50 and 100 mg/kg) inhibited both incidence and intensity of the audiogenic seizures which appeared at 6 h of ethanol withdrawal. l-NAME (200 mg/kg) produced a significant augmentation in both incidence and intensity of the catatonia in ethanol dependent rats. This dose of l-NAME also reduced the locomotor activity of both ethanol dependent and non-dependent rats. The locomotor inhibitory effect was more prominent in ethanol-dependent group. The catatonia precipitating effect of l-NAME was not prevented by l-arginine (1 g/kg, i.p.), a NO precursor, pretreatment. In the naive rats, l-NAME also did not produce catatonia. These results indicate that l-NAME has a catatonia precipitating effect during ethanol withdrawal in rats and this effect seems to be independent from NO mediated mechanisms.