Neurobehavioral effects of fipronil long term exposure in rats / Efeitos neurocomportamentais da exposição prolongada de ratos ao fibronil

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Fipronil is a phenylpyrazole insecticide with broad spectrum, developed to selectively inhibit insect GABA-gated chloride channels; both in Veterinary Medicine, and in Agriculture it has been used for the control of nuisances. Although several studies try to understand the mechanism of neuronal toxicity of pesticide in mammalian, there are few studies related to neurobehavioral effects. Thus, the present study investigated the effects of fipronil long term exposure in rats, being observed some behaviors connected to GABAergic system, as activity in open field, in elevated plus maze (EPM), as well as in the seizures induced by picrotoxinin and pentylenotetrazole. In addition, this study determinated the brain levels of some neurotransmitter as GABA, dopamine, noradrenaline, serotonin and metabolic levels and investigated liver, brain and kidney damage. Wistar rats received by intragastric (gavage) way during 28 days one of this treatment: fipronil (0,1, 1,0 or 10,0 mg/Kg) or distilled water; the rats behavior were evaluated in open field and elevated plus maze apparatus with system computer EthoVision®. There was a significant reduction of rearing in open field in rats treated with 10,0 mg/Kg of fipronil when compared with control rats. In the EPM, there was a decrease of distance moved in open arms and increase of time spent in closed arms to rats treated with 1,0 and 10,0 mg/Kg of fipronil when compared to control. It was still noticed the reduction in the time spent in open arms EPM in rats treated with 1,0 and 10,0 mg/Kg of fipronil when compared to control group. To calculate the minimum convulsant dose, was used the same treatment protocol and it was observed a significant reduction in picrotoxinin and pentylenotetrazole necessary dose to induction of seizure in animals treated with fipronil 10,0 mg/Kg. The level determination of neurotransmitters and their metabolites, it was observed the dopamine increasing in forebrain from fipronil treated rats by 10,0 mg/Kg. GABA levels decreased in fipronil treated rats striatum by 1,0 mg/Kg. Serotonin neurotransmitter was increased in fipronil treated rats forebrain by 1,0 mg/Kg to and its metabolite, 5HIAA, it was observed a levels decrease in fipronil forebrain treated rats by 0,1 e 1,0 mg/kg. There was decrease of 5HIAA levels in fipronil treated rats striatum by 0,1 e 1,0 mg/Kg. According to organ analyses, it was observed dose-response liver damage such as swelling liver cells. In conclusion, the data showed that fipronil administered in rats by 28 days caused behavioral effects related to central neurotransmitter alterations and hepatotoxicity.

ASSUNTO(S)

fipronil gaba seizure neurotransmission neurotransmissores comportamento animal fipronil gaba animal behavior

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