- 作者: Hong Zhu; Wu Zhou; Xiao R. Li; Tangen Ma; Ing K.Ho; Robin W. Rockhold
- 作者服務機構: Departments of Otolaryngology and Communicative Sciences and Pharmacology and Toxicology, Univerity of Mississippi Medical Center, Jackson, Miss., USA
- 中文摘要: --
- 英文摘要: Exposure to organophosphate insecticides induces un-desirable behavioral changes in humans, including anxi-ety and irritability, depression,cognitive disturbancesand sleep disorders.Little information currently existsconcerning the neural mechanisms underlying such be-havioral changes. The brain stem locus coeruleus(LC)could be a mediator of organophosphate insecticide-induced behavioral toxicities since it contains high levelsof acetylcholinesterase and is involved in the regulationof the sleep-wake cycle,attention,arousal,memory, andpathological processes, including anxiety and depres-sion.In the present study, using a multi-wire recordingtechnique, we examined the effects of methyl parathion,a commonly used organophosphate insecticide, on thefiring patterns of LC neurons in rats. Systemic adminis-tration of a single dose of methyl parathion(1 mg/kg,i.v.)increased the spontaneous firing rates of LC neurons by240% but did not change the temporal relationshipsamong the activities of multiple LC neurons.This dose ofmethyl parathion induced a 50%decrease in blood ace-tylcholinesterase activity and a 48%decrease in LC ace-tylcholinesterase activity. The methyl parathion-inducedexcitation of LC neurons was reversed by administrationof atropine sulfate, a muscarinic receptor antagonist,indicating an involvement of muscarinic receptors.Themethyl parathion-induced increase in LC neuronal activi-ty returned to normal within 30 min while the blood ace-tylcholinesterase activity remained inhibited for over 1 h.These data indicate that methyl parathion treatment canelicit excitation of LC neurons. Such excitation could con-tribute to the neuronal basis of organophosphate insecti-cide-induced behavioral changes in human.
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