Quantitative trait loci for acute behavioral sensitivity to paraoxon.
Genetic mechanisms responsible for organophosphate (OP)-induced behavioral changes remain obscure. In the present study, provisional quantitative trait loci (QTL) associated with acute sensitivity or insensitivity to hypolocomotion produced by the OP paraoxon were identified. Naive adult male and female mice of the BXD/Ty series (22 different BXD strains plus C57BL/6J and DBA/2J progenitor strains) received 0 or 0.25 mg/kg paraoxon (IP), immediately before placement in an activity chamber for a 30-min test. As expected, based on dose-response and time course studies with Swiss-Webster, C57BL/6, and DBA/2 mice, paraoxon treatment reduced locomotor activity in most, but not all BXD strains. Heritability (proportion of phenotypic variability attributed to genetic differences) was 0. 58 for the paraoxon treatment effect. Difference scores (strain mean for vehicle activity minus strain mean for paraoxon activity), and percent change in activity of paraoxon-treated mice compared to vehicle-treated mice were calculated for each BXD strain. QTL analyses using activity difference scores and percentage change in activity were conducted using a database with over 1300 unique genetic markers. Several provisional QTL found on different chromosomes were associated with the activity phenotype. Of these, several markers attained p<0.01 or greater. These were as follows: Chr 1: Ly9, p<0.006; Chr 6: D6Ncvs44, p<0.0005; Chr 9: D9Mit15, p<0. 003; Chr 11: D11Ncvs76, p<0.002; Chr 15: Tstap198, p<0.008. In addition, several markers on chromosome 3 approached p<0.01. Identified genes found near these regions include two plasma carboxylesterase alleles on chromosomes 6 and 9, a glutamate receptor subtype on chromosome 11 and a glycine receptor subunit on chromosome 11, raising the possibility that these genes could be the basis for these provisional QTLs.
Risinger
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Department of Behavioral Neuroscience, L470, Portland Alcohol Research Center, Oregon Health Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97201-3098, USA. risinger@ohsu.edu
Quick
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Belknap
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D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D007306:Insecticides / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D009043:Motor Activity / Q000187:drug effects / Q000235:genetics; D010261:Paraoxon / Q000494:pharmacology*; D010641:Phenotype; D019655:Quantitative Trait, Heritable; D013997:Time Factors
D007306:Insecticides; D010261:Paraoxon