ATIVIDADE ANTINOCICEPTIVA DO ÁCIDO MIRSINÓICO B / ANTINOCICEPTIVE ACTIVITY OF MIRSINOIC B ACID

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Mirsinoic B Acid (MBA) is a prenilate benzoic acid isolated from Rapanea sp. Various studies have shown that compounds of this type have antifungal, molluscicidal and antiparasitic activity. The objective of this study was to evaluate the role of MBA in the pain process, and the possible antinociceptive mechanisms involved, using some in vivo pharmacological nociceptive models. Male Swiss mice (Mus musculus) weighing 25 - 30 g, and male Wistar rats (Rattus norwegicus) weighing 250 300g were used in the assays. The pharmacological models used were the acetic acid, formalin, capsaicin, glutamate, hot plate, hyperalgesia (Randall-Sellitto), open field, and acute toxicity models, and the Artemia salina assay. The action mechanism was studied using the acetic acid model. MBA, administered intraperitonially (3 - 60mg/kg) caused a reduction in nocioconception induced by acetic acid, formalin, capsaicin and glutamate, and also when analyzed in the hot plate model. When administered orally (p.o. 150 500 mg/kg), MBA effectively reduced nociception in the acetic acid model. The antinociceptive effect of MBA (60mg/kg) was completely reverted when the animals was pre-treated with yoimbine (0.15 mg/kg, ip), prazosine (0.15 mg/kg, ip), atropine (1.0 mg/kg ip), L-arginine (600 mg/kg ip), PCPA (100mg/kg ip) and after bilateral adrenalectomy, but there was no change after pre-treatment with haloperidol (0.2 mg/kg ip), bicuculine ( 0.7 mg/kg ip), phaclofen (3 mg/kg ip), naloxone (1mg/kg ip), ondansetrone (0.5 mg/kg ip) and ketanserine (1 mg/kg ip). The acute toxicity effect of MBA was tested by injection of 2000 mg/kg v.o. In this test, no significant toxic effects were detected on the treated animals, compared with the control group, but the compound showed toxicity when tested in unicellular organisms. The effect of MBA on the animals locomotion was also studied, by the open field model. Pretreatment with the compound did not show any significant alterations in relation to rearing, but significantly reduced crossing, compared with the control. These data demonstrate that MBA has an important antinociceptive effect, interacting with the α-adrenergic, cholinergic, and nitric oxide systems, the hypotalamus-pituitary-adrenal axis and, in part, the serotoninergic system. There was no evidence of the antinociceptive effects of MBA on the dopaminergic, gabaergic and opioid systems. This study suggests, therefore, that MBA has powerful antinociceptive action and could be useful for the investigation and development of a new analgesic drug.

ASSUNTO(S)

farmacia antinocicepção mechanism of action produtos naturais mirsinoic b acid mecanismo de ação ácido mirsinóico antinociception

ACESSO AO ARTIGO

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