title: Behavioral and physiological effects of acute sublethal exposure to dimethoate on wood mice, Apodemus sylvaticus.
abstract: The effects on behavior and cholinesterase (ChE) of an OP pesticide, dimethoate, were examined in wood mice under laboratory conditions. Mice were administered 0, 5, 15, or 50 mg/kg intraperitoneal dimethoate and their behavior was recorded in an open field for one hour. In a second experiment, using only the 0 and the 50 mg/kg dose, mice were subjected to 10-min open field tests repeated at various time intervals during a 24-h period. Shortly after administration of dimethoate, there was a general, dose-dependent, behavioral depression that was characterized by increased inactivity and decreased grooming, rearing, and sniffing. The introduction of a novel object in the open field failed to elicit any reaction in mice treated with the two highest doses of dimethoate. The behavioral impairment completely disappeared 6 h after treatment. A stereotyped compulsive grooming was also observed in the first 30 min after administration of the two highest doses. Exposure to dimethoate caused a dose-dependent decrease in ChE activity in the brain and in serum. Behavioral impairment was associated with maximum levels of ChE inhibition of 65-75% (brain) and 75-85% (serum). Recovery of ChE activity lagged behind that of behavioral impairment and started 3-6 h after dimethoate administration. The possible implications for free-living wood mice which inhabit cereal fields and may be exposed to OPs are discussed.
authors.affiliation: Natural Environment Research Council, Institute of Terrestrial Ecology, Monks Wood, Abbots Ripton, Huntingdon, Cambridgeshire, PE17 2LS, United Kingdom.
authors.forename: G
authors.initials: G
authors.lastname: Dell'Omo
authors.forename: R F
authors.initials: RF
authors.lastname: Shore
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D002800:Cholinesterase Inhibitors / Q000633:toxicity*; D003863:Depression / Q000139:chemically induced; D004117:Dimethoate / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D007306:Insecticides / Q000633:toxicity*; D008297:Male; D009115:Muridae / Q000502:physiology*
chemical_list: D002800:Cholinesterase Inhibitors; D007306:Insecticides; D004117:Dimethoate