Acetylcholinesterase, in the olfactory organ of the common carp Cyprinus carpio (Teleost, Cyprinidae): Characterization of molecular forms in vitro and in vivo inhibition by carbofuran

The use of pesticides in agriculture and in insect control has been creating a potential danger to aquatic life and human health. Acetylcholinesterase, an enzyme regulating nerve-impulse transmission, is reported to be inhibited by carbamates and organophosphates in many living systems including aquatic organisms. AChE is also present in the entire olfactory organ of the common carp Cyprinus carpio. The native molecular forms of AChE present in olfactory organ have been characterized by sedimentation analysis in sucrose gradients. AChE exists as gobular and asymmetric forms. The reduction of olfactory organ AChE activity is already perceptible at sublethal concentrations of carbofuran. The results show an inhibition of olfactory organ AChE ranging from 33,4\% to 49,3\% after 48 hours. This makes the AChE activity a potential biochemical indicator of toxic stress in fishes and a sensitive test for the presence of carbamates and organophosphates in water.