title: The synaptosomal membrane bound ATPase as a target for the neurotoxic effects of pyrethroids, permethrin and cypermethrin.
abstract: Pyrethroids are used widely as insecticides both in agriculture and in households. A cellular target of pyrethroids is the sodium channel in the membrane. In the present study, the activity of the membrane bound integral protein ATPase was studied as a biomarker for the membrane effect of the pyrethroids permethrin and cypermethrin. Male Sprague-Dawley rats were used for cerebral synaptosome preparation. The isolation of synaptosomes was performed with the Percoll gradient method. Both total ATPase and Mg(2+) activated ATPase were studied by determining inorganic phosphate liberated from the substrate ATP. One hour exposure to permethrin (Biokill) and cypermethrin (Ripcord) insecticide products affected ATPase activities. The activity of Na(+), K(+) ATPase decreased dose-dependently in 10-50 microM concentrations of permethrin, and Mg(2+) activated ATPase increased over twofold in the same concentrations of the active components. The effect of the cypermethrin compound Ripcord was not clearly dose-dependent. The activity of total ATPase was almost entirely lost in the concentrations of 100 microM of permethrin and cypermethrin. The results support the idea that membrane ATPases are one target of the neurotoxic effect of pyrethroid compounds.
authors.affiliation: Medical School, 33014 University of Tampere, Tampere, Finland. irma.kakko@uta.fi
authors.forename: Irma
authors.initials: I
authors.lastname: Kakko
authors.forename: Tarja
authors.initials: T
authors.lastname: Toimela
authors.forename: Hanna
authors.initials: H
authors.lastname: Tähti
mesh_terms: D000818:Animals; D002462:Cell Membrane; D004305:Dose-Response Relationship, Drug; D007306:Insecticides / Q000494:pharmacology* / Q000633:toxicity*; D008274:Magnesium; D008297:Male; D026023:Permethrin / Q000494:pharmacology* / Q000633:toxicity*; D011722:Pyrethrins / Q000494:pharmacology* / Q000633:toxicity*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015222:Sodium Channels; D000254:Sodium-Potassium-Exchanging ATPase / Q000494:pharmacology*; D013574:Synaptosomes / Q000187:drug effects* / Q000201:enzymology*
chemical_list: D007306:Insecticides; D011722:Pyrethrins; D015222:Sodium Channels; C017160:cypermethrin; D026023:Permethrin; D000254:Sodium-Potassium-Exchanging ATPase; D008274:Magnesium