Abstracts / Toxicology Letters 196S (2010) S37–S351 S225 (0.23% yield). For this, male Wistar rats (N = 6 by group) of the exper- imental group received by gavage 10, 30 and 100 mg/kg of MCT; the control group received only water (1 ml/kg). During experiments, the rats were observed on 15, 30, 45, 60, 75, 90, 105, 120, 150, 180 and 240 min, and for 14 days after gavage. In all doses adminis- tered, the toxicity was evident during 240 min after ingestion of MCT. During the whole the experiment all animals had a decreased on the corneal reflex. The piloerection was also noted in these rats. Although, a reduced auricular reflex and tail squeeze were observed after the 30 and 100 mg/kg. These doses also produced palpebral ptosis in all rats, however, only the 100 mg/kg induced tremors. No deaths or macroscopic alterations in the tissues were seen after 14 days of treatment. It was concluded that the MCT alkaloid con- tained in C. spectabilis was neurotoxic to male rats at 10, 30 and 100 mg/kg in a dose-dependent and time-dependent manner. doi:10.1016/j.toxlet.2010.03.753 P207-026 Behavioural toxicity of an oral chronic administration (90 days) of raw cow’s milk contaminated with polychlorinatedbiphenyls (PCBS) in adult male rats H. Schroeder, G. Streit, M. Condé, G. Rychen, C. Feidt URAFPA, INRA USC340, France Polychlorinated biphenyls (PCBs) are persistent organic pollutants of risk for the human health because of their ability to accumu- late in food and their highly toxic properties, especially for the brain. Recent findings demonstrate that these contaminants can be found in significant quantities in the milk of lactating women and ruminants, suggesting a greater danger for milk consumers like newborns and infants. Thus, the objective of the present study was to investigate the behavioural toxicity of a chronic administration of PCB-contaminated cow milk in adult rats. Two groups of Wistar male rats (n = 10) were used. The “treated” group was daily admin- istered by gavage with 0.5 ml/100 g b.w. of PCB-contaminated milk for 90 days. Respective milk concentrations of “dioxin-like” and “non dioxin-like” PCBs were of 11.4 pg WHO-TEQ and 37.9 ng/g fat weight. This corresponded to a daily intake of 1.8 pg WHO-TEQ/kg b.w. for “dioxin-like” PCBs, and 6.1 ng/kg b.w. for “non dioxin-like” compounds. In parallel, the control animals received the same vol- ume of a commercial milk preparation. At the end of the period of exposure, the animals were tested for their behavioural perfor- mances related to locomotor activity in the open-field, locomotor coordination in the Locotronic ® , anxiety in the elevated-plus maze, and spatial learning and memory in the T-maze and the eight-arm maze. The results showed a significant decrease in general activ- ity of rats that were fed with PCB-contaminated milk in several tests like the open-field, the elevated plus maze, and the T-maze, whereas the body weight, the level of anxiety, the learning perfor- mances and the locomotor coordination were unaffected by PCBs. In conclusion, such results showed that the chronic ingestion of PCBs present in the milk from an accidental pollution is able to induce subtle behavioural changes, and then can be potentially toxic for the brain. doi:10.1016/j.toxlet.2010.03.754 P207-027 Effects of environmental contaminants exposure on spatial orientation of visual attention in children: A study from arctic QUEBEC A.A. Ethier 1 , C. Polevoy 2 , G. Muckle 3 , C. Bastien 3 , E. Dewailly 4 , P. Ayotte 4 , P. Plusquellec 4 , S. Jacobson 5 , J. Jacobson 5 , D. Saint-Amour 2 1 University of Montreal, Canada, 2 Sainte-Justine Hospital, Canada, 3 Laval University, Canada, 4 Public Health Research Unit, Canada, 5 Department of Psychiatry and Behavioral Neurosciences, Wayne State University, United States The Inuit from Arctic Quebec (Canada) are highly exposed to mercury (Hg) and polychlorinated biphenyls (PCBs) due to their bioaccumulation in fish and marine diet. Exposure to these envi- ronmental contaminants has been identified as a risk factor for attention deficits. The present study aimed at assessing the impact of environmental contaminants on spatial attention in a cohort of Inuit children at school age using a Posner cue-target paradigm. Thirty-two Inuit children (mean age = 10.3 years) participated in this follow-up study. Blood concentrations of Hg, lead and PCBs were measured at birth from cord blood samples and at the time of testing. Children were instructed to detect a pre-cued target that might appear on the left or on the right of the fixation point as quickly as possible. Reaction times (RT) of valid trials (cues and targets on the same side) and invalid trials (cues and targets on dif- ferent sides) as well as response types (hits, omissions, false alarms and correct withholds) were measured. The association between performances and contaminant levels was obtained using Pearson correlations and multiple regression analyses. Results showed a significant correlation between RT and PCBs at the time of testing (r = .60, p = .006). As such, high level of PCBs expo- sure during postnatal development was associated with longer reaction times. In addition, prenatal PCB exposure was signifi- cantly associated with a greater number of missing targets (r = .58, p = .003), suggesting vigilance impairment. Multivariate regression revealed that this prenatal effect remained significant after adjust- ment for postnatal PCB exposure and other covariates (beta = .67, p = .012). This study shows that chronic PCB exposure alters spatial attention and vigilance in school-age children. doi:10.1016/j.toxlet.2010.03.755 P207-028 Chronic dietary and acute exposure to chlorpyrifos in rats: Neurobehavioural and neurochemical correlates J. Barril 1 , C. López-Granero 2 , D. Cardona 2 , E. Giménez 2 , F. Sánchez-Santed 2 , M.D.L.C. Pellín 1 , J. Esteban 1 , F. Ca ˜ nadas 2 1 Universitat Miguel Hernández d’Elx, Spain, 2 Universidad de Almería, Spain The primary molecular targets for the acute and delayed toxicities of organophosphates (OPs) have been clearly identified. However, much less is known about the possible consequences of low-dose long-term exposure to such compounds. Chlorpyrifos (CPF) is a common OP that has been widely used as an extensive agricul- ture and even household insecticide. The present study examined the behavioural effects of CPF chronic dietary and CPF, parathion (PTN) and O,O ′ -diisopropyl phosphorofluoridate (DFP) subcuta- neous acute exposure on spatial working memory and impulsivity in rats. Three-month male Wistar rats were injected s.c. with