Atividade Antinociceptiva, em dores agudas, de um novo fator extraído da secreção cutânea de Rhinella jimi (Amphibia Anura) / Antinociceptive activity in acute pain, a new factor extracted from the skin secretion of Rhinella jimi (Amphibia - Anura)

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

22/12/2009

RESUMO

Pain control has been an important focus of health for a long time. The ideal analgesic should be powerful, promoting maximum pain relief, but must submit a minimum adverse symptoms. The opioid agonists are used in treatment of intense acute pains and chronic pains in terminal patients, although they present important side effects, such as constipation, respiratory depression and physical and psychological addiction. Thus, several researches are take care actually to development new drugs more potent than morphine and without these side effects. The venom of Rhinella jimi amphibian is extremely rich in biological activity substances secreted from parotoid glands, that have been extensively studied to develop new therapeutics. This paper aims to study antinociceptive effects in intense acute pains of a new factor isolated from skin secretions of Rhinella jimi. We purified a new factor from skin secretions of Rhinella jimi, which presented intense antinociceptive activity in animal models of experimental acute pains: the acid acetic writing assay, the formalin test, the hot plate test and the tail flick test. In these tests, it was used 0,5, 1 and 2mg/Kg of the factor by oral route and 0,25, 0,5 and 1mg/Kg by intraperitoneal route. In the acid acetic writing assay, the factor reduced significantly the number of contortions, showing a dose-dependent effect, and it was mol to mol 240% more potent than morphine (5mg/Kg). In the formalin test, the factor reduced significantly the time of response in phases 1 and 2, showing dose-dependent effects and it was mol to mol 1035 and 305% more potent than morphine in phases 1 and 2, respectively. In the hot plate test, the factor increased significantly the time of permanence on the hot plate, showing a dose-dependent effect and it was mol to mol 1665% more potent than morphine. In the tail flick test, the factor increased significantly the time of permanence of the tail in hot water, showing a dose-dependent effect and it was mol to mol 310% more potent than morphine. These results show that the antinocicetive action of the factor, injected by i.p. and v.o. routes, didnt involve the opioid system in experimental models of acute pains in mice, since it was not reversed by naloxone. In concluding, these antinocicetive effects were peripheral and central acting in both, neurogenic and inflammatory acute pains. In the future, this factor could be used for development of new therapeutics.

ASSUNTO(S)

antinocicepção, dor aguda, anfíbios fisiologia antinociception acute pain amphibians

ACESSO AO ARTIGO

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