Comparative in vitro and in vivo effects of chlorpyrifos oxon in the outbred CD‐1 mouse (Mus musculus) and great plains toad (Anaxyrus cognatus)

Abstract

We compared biochemical, functional, and behavioral responses to the organophosphorus anticholinesterase chlorpyrifos oxon (CPO) in mice (Mus musculus, CD-1) and toads (Anaxyrus cognatus, Great Plains toad). Toads were substantially less sensitive to acute lethality of CPO based on the maximum tolerated (nonlethal) dose (toads, 77 mg/kg; mice, 5.9 mg/kg). Sublethal exposures led to classical signs of toxicity (increased involuntary movements, autonomic secretions) in mice but hypoactivity in toads. Motor performance in an inclined plane test was not affected by CPO in mice but was altered at the highest dosage in toads. Acetylcholinesterase (AChE), butyrylcholinesterase, monoacylglycerol lipase, and fatty acid amide hydrolase activities in brain were inhibited in mice but not in toads, and fatty acid amide hydrolase activity in the liver was inhibited in both species. Toad brain AChE was less sensitive to in vitro inhibition by CPO (50% inhibitory concentration [IC50; 20 min, 37 °C], 101 vs 7.8 nM; IC50 [20 min, 26 °C], 149 vs 6.2 nM), and studies of inhibitor kinetics indicated substantially lower anticholinesterase potency of CPO against the toad brain enzyme. Using an in vitro indirect inhibition assay, preincubation of CPO with toad brain homogenate was more effective than an equivalent mouse brain homogenate at reducing CPO potency. These data suggest that the relatively low sensitivity of toads to cholinergic toxicity is based on the low sensitivity of brain AChE, which in turn may be attributable to more effective target-site detoxification. Environ Toxicol Chem 2018;37:1898-1906. © 2018 SETAC.

Effects of Chlorpyrifos on Cholinesterase and Serine Lipase Activities and Lipid Metabolism in Brains of Rainbow Trout (Oncorhynchus mykiss)

“…Brain tissues were homogenized 1:10 (w/v) in phosphate buffered saline (100 mM phosphate containing 1.54 M NaCl, pH 7.4) for measurements of AChE, BChE, MAGL, and FAAH activity. AChE, BChE, and MAGL were measured using a photometric assay (Anderson et al, 2018) based on the method of Ellman et al (1961). A cocktail containing substrate (1 mM acetylthiocholine, 1 mM butyrylthiocholine, or 0.1 mM 2-arachidonoyl thioglycerol) and 0.1 mM 5,5 0 -dithio-bis-(2-nitrobenzoic acid) in Tris-E (10 mM Tris-HCl containing 1 mM EDTA, pH 7.2) was added to start the reaction.…”

Emerging techniques in food science: the resistance of chlorpyrifos pesticide pollution against arc and dielectric barrier discharge plasma

“…Also, a tolerance level of 100 ppb is defined for chlorpyrifos residues, per se, in or on food commodities (Regulations, 2020). It was revealed that consumption of the residues of this chemical can result in diarrhea, frequent urination, abnormal sweating, salivation, lacrimation, genotoxicity, neurochemical changes, neurobehavioral disorder, and abnormal birth outcomes (Anderson et al, 2018;Farkhondeh et al, 2020;Foong et al, 2020). Therefore, its indoor application was banned by EPA since the early 21st century.…”