- 作者: Hong Zhu Robin W. Rockhold Rodney C. Baker Robert E. Kramer Ing K. Ho
- 作者服務機構: Department of Pharmacology and Toxicology, University of mississippl medical center, Jackson, Miss., USA
- 中文摘要: --
- 英文摘要: The effects of a single or repeated dermal administrationof methyl parathion on motor function, learning andmemory were investigated in adult female rats and cor-related with blood cholinesterase activity. Exposure to asingle dose of 50 mg/kg methyl parathion (75% of thedermal LD ) resulted in an 88% inhibition of blood cho-linesterase activity and was associated with severe acutetoxicity. Spontaneous locomotor activity and neuromus-cular coordination were also depressed. Rats treatedwith a lower dose of methyl parathion, i.e. 6.25 or12.5 mg/kg, displayed minimal signs of acute toxicity.Blood cholinesterase activity and motor function, how-ever, were depressed initially but recovered fully within1-3 weeks. There were no delayed effects of a singledose of methyl parathion on learning acquisition ormemory as assessed by a step-down inhibitory avoid-ance learning task. Repeated treatment with 1 mg/kg/daymethyl parathion resulted in a 50% inhibition of bloodcholinesterase activity. A decrease in locomotor activityand impairment of memory were also observed after 28days of repeated treatment. Thus, a single dermal expo-sure of rats to doses of methyl parathion which are lowerthan those that elicit acute toxicity can cause decrementsin both cholinesterase activity and motor function whichare reversible. In contrast, repeated low-dose dermaltreatment results in a sustained inhibition of cholinester-ase activity and impairment of both motor function andmemory.
- 中文關鍵字: --
- 英文關鍵字: Methyl parathion. Acetylcholinesterase. Dermal Exposure. Learning. memory. Motor Function