Hypnotic, anticonvulsant and muscle relaxant effects of Rubus brasiliensis. Involvement of GABA(A)-system

Rubus brasiliensis hexanic fraction induced anxiolysis in rodents, which wa s reversed by flumazenil, a specific GABA(A)-benzodiazepine receptor antago nist (Nogueira et al., 1998a,b). Then, we investigated if this hexanic frac tion was able to induce hypnotic, anticonvulsant and muscle relaxant effect s, and the involvement of GABA(A)-system. The hexanic fraction (50, 100, 15 0 and 300 mg/kg, vo) was administered to male Swiss mice, 30 min before the tests. Only the dose of 300 mg/kg of this fraction decreased the latency a nd increased sleeping time in the barbituric-hypnosis test (sodium pentobar bital, 30 mg/kg, ip), prevented the pentylenetetrazol seizures (70 mg/kg, i p) and induced muscle relaxant (inclined plane) in 100% of animals. These e ffects were reversed by flumazenil (3 mg/kg, ip). In conclusion: (1) R. bra siliensis hexanic fraction induced hypnotic, anticonvulsant and muscle rela xant effects, in mice, and the GABA(A)-benzodiazepine receptor may play an important role in the effects of this fraction; (2) it is strongly suggeste d that this fraction contains a benzodiazepine-like principle. (C) 2000 Els evier Science Ireland Ltd. All rights reserved.