Inhibition of acetylcholinesterase in guppies (Poecilia reticulata) by chlorpyrifos at sublethal concentrations: Methodological aspects
Acetylcholinesterase activity is a potential biochemical indicator of toxic stress in fish and a sensitive parameter for testing water for the presence of organophosphates. A number of methodological aspects regarding the determination of the in vivo effect of chlorpyrifos on acetylcholinesterase in guppies have been investigated. It was found that with acetylthiocholine as a substrate, the contribution of pseudocholinesterase to the total cholinesterase activity can be neglected. Protection of acetylcholinesterase of guppies exposed to chlorpyrifos from additional, artifactual in vitro enzyme inhibition during homogenization is necessary. Very low concentrations of acetone in the exposure medium, resulting from dilution of the stock solution of chlorpyrifos in acetone, can result in large decreases in the oxygen content of this medium. This may affect the uptake rate of the toxic compound and, thereby, cholinesterase inhibition. Very low, sublethal concentrations of chlorpyrifos result in high inhibition levels of acetylcholinesterase (80-90%) in guppies within 2 weeks of continuous exposure. Recovery of the enzyme activity occurs after the exposed animals are kept in clean medium for 4 days, but the rate of recovery is considerably lower than the rate of inhibition.
- Research Organization:
- Institute of Pesticide Research, Wageningen (Netherlands)
- OSTI ID:
- 5823062
- Journal Information:
- Ecotoxicol. Environ. Saf.; (United States), Vol. 17:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
CHOLINESTERASE
ENZYME ACTIVITY
FISHES
SENSITIVITY
ORGANIC PHOSPHORUS COMPOUNDS
TOXICITY
WATER POLLUTION
BIOLOGICAL INDICATORS
BIOLOGICAL RECOVERY
ENZYME INHIBITORS
INHIBITION
MONITORING
ANIMALS
AQUATIC ORGANISMS
CARBOXYLESTERASES
ENZYMES
ESTERASES
HYDROLASES
ORGANIC COMPOUNDS
POLLUTION
RECOVERY
VERTEBRATES
520200* - Environment
Aquatic- Chemicals Monitoring & Transport- (-1989)
560300 - Chemicals Metabolism & Toxicology