Relative potencies for acute effects of pyrethroids on motor function in rats.
Toxicol Sci
; 89(1): 271-7, 2006 Jan.
Article
em En
| MEDLINE
| ID: mdl-16221961
ABSTRACT
The prevalence of pyrethroids in insecticide formulations has increased in the last decade. A common mode-of-action has been proposed for pyrethroids based on in vitro studies, which includes alterations in sodium channel dynamics in nervous system tissues, consequent disturbance of membrane polarization, and abnormal discharge in targeted neurons. The objective of this work was to characterize individual dose-response curves for in vivo motor function and calculate relative potencies for eleven commonly used pyrethroids. Acute oral dose-response functions were determined in adult male Long Evans rats for five Type I (bifenthrin, S-bioallethrin, permethrin, resmethrin, tefluthrin), five Type II (beta-cyfluthrin, lambda-cyhalothrin, cypermethrin, deltamethrin, esfenvalerate) and one mixed Type I/II (fenpropathrin) pyrethroids (n = 8-18 per dose; 6-11 dose levels per chemical, vehicle = corn oil, at 1 ml/kg). Motor function was measured using figure-8 mazes. Animals were tested for 1 h during the period of peak effects. All pyrethroids, regardless of structural class, produced dose-dependent decreases in motor activity. Relative potencies were calculated based on the computed ED30s. Deltamethrin, with an ED30 of 2.51 mg/kg, was chosen as the index chemical. Relative potency ratios ranged from 0.009 (resmethrin) to 2.092 (esfenvalerate). Additional work with environmentally-based mixtures is needed to test the hypothesis of dose-additivity of pyrethroids.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Piretrinas
/
Relação Dose-Resposta a Droga
/
Inseticidas
/
Atividade Motora
Tipo de estudo:
Risk_factors_studies
Limite:
Animals
Idioma:
En
Revista:
Toxicol Sci
Assunto da revista:
TOXICOLOGIA
Ano de publicação:
2006
Tipo de documento:
Article
País de afiliação:
Estados Unidos