Hypnotic, anticonvulsant and muscle relaxant effects of Rubus brasiliensis. Involvement of GABA(A)-system.
Rubus brasiliensis hexanic fraction induced anxiolysis in rodents, which was reversed by flumazenil, a specific GABA(A)-benzodiazepine receptor antagonist (Nogueira et al., 1998a,b). Then, we investigated if this hexanic fraction was able to induce hypnotic, anticonvulsant and muscle relaxant effects, and the involvement of GABA(A)-system. The hexanic fraction (50, 100, 150 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 and increased sleeping time in the barbituric-hypnosis test (sodium pentobarbital, 30 mg/kg, ip), prevented the pentylenetetrazol seizures (70 mg/kg, ip) and induced muscle relaxant (inclined plane) in 100% of animals. These effects were reversed by flumazenil (3 mg/kg, ip).


CONCLUSIONS
(1) R. brasiliensis hexanic fraction induced hypnotic, anticonvulsant and muscle relaxant effects, in mice, and the GABA(A)-benzodiazepine receptor may play an important role in the effects of this fraction; (2) it is strongly suggested that this fraction contains a benzodiazepine-like principle.
Nogueira
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Neuropharmacology Laboratory, Centre of Toxicological Assistance, Bioscience Institute, UNESP, CEP: 18618-000, -SP, Botucatu, Brazil.
Vassilieff
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VS
D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology*; D001463:Barbiturates / Q000494:pharmacology; D001938:Brazil; D003975:Diazepam / Q000494:pharmacology; D005442:Flumazenil / Q000494:pharmacology; D018757:GABA Modulators / Q000494:pharmacology; D006586:Hexanes; D006993:Hypnotics and Sedatives / Q000494:pharmacology*; D008297:Male; D051379:Mice; D009125:Muscle Relaxants, Central / Q000494:pharmacology*; D010433:Pentylenetetrazole; D010936:Plant Extracts / Q000494:pharmacology; D010946:Plants, Medicinal / Q000737:chemistry*; D011963:Receptors, GABA-A / Q000187:drug effects*; D012640:Seizures / Q000139:chemically induced / Q000517:prevention & control
D000927:Anticonvulsants; D001463:Barbiturates; D018757:GABA Modulators; D006586:Hexanes; D006993:Hypnotics and Sedatives; D009125:Muscle Relaxants, Central; D010936:Plant Extracts; D011963:Receptors, GABA-A; D005442:Flumazenil; D003975:Diazepam; D010433:Pentylenetetrazole