Effects of 3-amino-1,2,4-triazole on ethanol-induced open-field activity: evidence for brain catalase mediation of ethanol's effects.

The role of brain catalase in the mediation of ethanol's effects on motor activity was investigated. Male Long-Evans rats were pretreated with i.p. injections of the catalase inhibitor, 3-amino-1,2,4-triazole (AT) (1 g/kg) or saline (S). Four hours later, animals in each group received i.p. injections of one of two doses of ethanol (ETOH) [1.0 g/kg (E1) or 2.0 g/kg (E2)] or one of two volumes of distilled water (W1 or W2). Ten minutes after the administration of these agents, animals were placed in open-field chambers and motor activity was recorded during a 10-min testing period. Results indicated that the motor depression produced by 2.0 g/kg of ETOH was significantly attenuated in AT pretreated rats (group AT-E2). AT pretreatment, however, had no effect on motor activity for subjects injected with 1.0 g/kg ethanol or water. Total brain catalase activity in AT-pretreated animals was 15% of control animals. No differences in blood ethanol levels were observed between AT- and S-pretreated animals. An interaction between ethanol and AT at the level of the central nervous system is suggested. The results of the present study suggest that brain catalase activity may be involved in ethanol's effects. They also provide further support for the notion that acetaldehyde may be produced directly in the brain via catalase and that it may be a factor mediating some of ethanol's central effects.