Atividade antinociceptiva do geraniol: estudos comportamentaise eletrofisiológicos

The high incidence of pain in the general population has encouraged research about this theme. Products derived from plant species have been widely used in the pharmacological treatment of pain relief. Recent studies have reported the important role of monoterpenes, active compounds found in the essential oils of aromatic plants, having relevant analgesic and anti-inflammatory potential. The geraniol (GER) is a monoterpenic alcohol, found in >160 essential oil of plant species, especially Cymbopogon gender. In the literature consulted, several biochemical and pharmacological properties are shown of GER: antitumor, antimicrobial, antiinflammatory, antioxidant, gastric and intestinal protector, neuroprotective and antiarrhythmic. In this study was evaluated the antinociceptive activity of GER, not yet reported, by animal behavioral and electrophysiological in vitro models. Male and female adult Swiss mice were used. Initially the acute toxicity of GER was investigated by calculating the lethal dose 50 (LD50) by intraperitoneal (i.p.) (= 199.9 mg/kg) and oral (p.o.) (> 1 g/kg). In psychopharmacological screening, after the administration of single doses of GER (i.p. and p.o.), behavioral changes were observed indicating a depressant profile on the central nervous system (CNS) and/or peripheral nervous system (SNP), and relevant antinociceptive effect of geraniol. Therefore, more specific antinociceptive property evaluation tests were performed. The GER (12.5, 25 or 50 mg/kg i.p. and 50 or 200 mg/kg p.o.) decreased (p160 espécies vegetais, especialmente do gênero Cymbopogon. Na literatura consultada, pesquisas apontam várias propriedades bioquímicas e farmacológicas para o GER: antitumoral, antimicrobiana, anti-inflamatória, antioxidante, de proteção gástrica e intestinal, neuroprotetora e antiarrítmica. Neste estudo foi avaliada a atividade antinociceptiva do GER, ainda não relatada, mediante modelos animais comportamentais e eletrofisiológicos in vitro. Foram utilizados camundongos machos e fêmeas Swiss adultos. Inicialmente, foi investigada a toxicidade aguda do GER mediante cálculo da dose letal 50 (DL50) pela via intraperitoneal (i.p.) (=199,9 mg/kg) e oral (v.o.) (>1 g/kg). Na triagem psicofarmacológica, após a subministração de doses únicas de GER (i.p. e v.o.) foram observadas alterações comportamentais que indicaram perfil depressor do sistema nervoso central (SNC) e/ou periférico (SNP), e relevante efeito antinociceptivo do geraniol. Portanto, foram realizados testes comportamentais de avaliação de propriedade antinociceptiva mais específicos. O GER (12,5; 25 e 50 mg/kg i.p. e 50 ou 200 mg/kg v.o.) reduziu (p