Article

Pesticide resistance in wild mammals--mechanisms of anticoagulant resistance in wild rodents.

Laboratory of Toxicology, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo.
The Journal of Toxicological Sciences (Impact Factor: 1.38). 09/2008; 33(3):283-91. DOI: 10.2131/jts.33.283
Source: PubMed

ABSTRACT Warfarin is commonly used worldwide as a rodenticide. It inhibits coagulation of blood by inhibiting vitamin K 2,3-epoxide reductase (VKOR) activity. An inadequate supply of vitamin K blocks the production of prothrombin and causes hemorrhage. It has been reported that repeated or long-term treatments with this drug cause resistance in wild rodents. However, the mechanism of warfarin resistance in rodents is still not known precisely. Recent studies reported and identified the function of the molecule, vitamin K epoxide reductase complex subunit 1 (VKORC1), which is the main unit of VKOR. An amino acid substitution in VKORC1 is one of the supposed mechanisms of warfarin resistance. An accelerated detoxification system involving cytochrome P450 (CYP) could also cause the rodenticide resistance. Administration of SKF-525A, a potent inhibitor for P450, increased the mortality due to reduction of warfarin metabolism in warfarin-resistant rats. Meanwhile, the appearance of warfarin-resistant rodents has led to the development of the more effective and toxic rodenticide superwarfarin, which is widely used in Europe and the USA. However, animals resistant to this second-generation rodenticide have already been reported in Europe. In this review, we focus on the mechanism and the pleiotropic effects of pesticide resistance in wild rodents.

0 Bookmarks
 · 
113 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Twenty-three 7-alkoxycoumarins and related analogs were synthesized from 7-hydroxycoumarin by treatment with various alkyl/aryl/acyl halides and potassium carbonate in DMF. Their antifeedant and termiticidal activities against Coptotermes formosanus Shiraki were examined. Among the 23 compounds and control, 7-cyclohexyloxycoumarin (2k), exhibited the highest termiticidal activity in no-choice test, followed by 7-(4-nitrophenoxy)coumarin (2q), and 7-(2-butynyloxy)coumarin (2u) at 5 μmol/disc. On the other hand, all of 7-alkoxycoumarins showed antifeedant activity except 7-hexadecyloxycoumarin (2i) and 7-octadecyloxycoumarin (2j), while 7-ethoxycoumarin (2b) demonstrated the highest antifeedant activity. The results suggested that a presence of cyclohexyloxy and aryloxy groups at C-7 position of coumarin skeleton was found to be important for the termiticidal and antifeedant activities. Arylalkoxy groups having methoxy groups at benzene ring, alkenoxy, and alkynoxy groups led to analogs with good termiticidal activity, while the incorporation of alkoxy groups with longer alkyl chains tended to reduce both the termiticidal and antifeedant activities.
    International Biodeterioration & Biodegradation 10/2012; 74:129–135. · 2.24 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We studied the prevalence of anticoagulant rodenticides (ARs) in the liver of 344 individuals representing 11 species of predatory wildlife that were found dead in the Mediterranean region of Spain (Catalonia and Majorca Island). Six different ARs (brodifacoum, bromadiolone, difenacoum, flocoumafen, difethialone, warfarin) were found in the liver of 216 (62.8%) animals and >1 AR co-occurred in 119 individuals (34.6%). The occurrence of ARs was positively correlated with the human population density. Catalonia and Majorca showed similar prevalence of AR detection (64.4 and 60.4%, respectively), but a higher prevalence was found in the resident population of Eurasian scops owl (Otus scops) from Majorca (57.7%) compared to the migratory population from Catalonia (14.3%). Birds of prey had lower levels of bromadiolone than hedgehogs, whereas no difference was found for other ARs. The risk of SGAR poisoning in wild predators in NE Spain is believed to be elevated, because 23.3% of the individuals exhibited hepatic concentration of ARs exceeding 200ng/g. Copyright © 2014 Elsevier B.V. All rights reserved.
    Science of The Total Environment 12/2014; 511C:259-267. · 3.16 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The industrial compound 4-vinylcyclohexene diepoxide (VCD) destroys ovarian follicles and reduces fertility in rodents, but to date VCD has not been tested in species that experience seasonal anestrus. To determine if VCD destroys follicles when administered during reproductive quiescence, Siberian hamsters were treated with VCD (240mg/kg i.p. daily for 10 days) during short days, and outcomes were compared with reproductively active females that were maintained and treated in long days. Primordial follicle numbers were significantly reduced by VCD under both day lengths, and reproductive quiescence in short days did not appear to render the ovaries less susceptible to VCD-induced follicle depletion. Independent of day length and reproductive state, VCD-treated hamsters weaned substantially fewer offspring than controls. These results suggest that time of year may not be an important consideration for optimizing use of VCD in the field when the target pest species is a seasonally breeding rodent. Copyright © 2014. Published by Elsevier Inc.
    Reproductive Toxicology 12/2014; 51. · 2.77 Impact Factor