- 作者: Robert E. Kramer, Susan E . Wellman, Hong Zhu, Robin W. Rockhold, Rodney C. Baker
- 作者服務機構: Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Miss., USA
- 中文摘要: --
- 英文摘要: or its active metabolite methyl paraoxon. The more grad-ual and prolonged inhibition of cholinesterase caused bydermal administration is consistent with disposition ofmethyl parathion at a site from which it or methylparaoxon is only slowly distributed. Thus, dermal expo-sure to methyl parathion may pose the greatest risk forlong-term adverse effects.Time-dependent changes in blood cholinesterase activi-ty caused by single intravenous, oral or dermal adminis-tration of methyl parathion to adult female rats weredefined. Intravenous and oral administration of 2.5 mg/kg methyl parathion resulted in rapid (<60 min) de-creases in cholinesterase activity which recovered fullyin vivo within 30-48 h. In contrast, spontaneous reactiva-tion of cholinesterase in vitro was complete within 6 h at37 C. Dermal administration of methyl parathion causeddose-dependent inhibition of cholinesterase activitywhich developed slowly (≧6 h) and was prolonged(≧48 h). Time- and route-dependent effects of methylparathion on cholinesterase activity in brain and othertissues generally paralleled its effects on activity inblood. In conclusion, pharmacodynamics of methylparathion differ substantially with route of exposure.Recovery of cholinesterase in vivo after intravenous ororal exposure may partially reflect spontaneous reactiva-tion and suggests a rapid clearance of methyl parathion
- 中文關鍵字: --
- 英文關鍵字: Rat, Acetylcholinesterase, Methyl parathion, Methyl paraoxon, Pharmacokinetics, Pharmacodynamics, Organophosphorus insecticides