L'acétylcholinestérase des poissons, cible des organophosphorés et des carbamates. Caractérisation du gène et des formes moléculaires de l'enzyme chez Danio rerio. Effets des anticholinestérasiques

Abstract

Acetylcholinesterase (AChE) is a key component of the cholinergic synapse where it terminates the action of ACh. Inhibition of AChE is the basis for some agricultural treatments against insects and nematodes. Wildlife (especially fishes) and domestic animals are often exposed to these treatments and the measure of the remaining AChE activity is a reliable marker of their exposition. Such an inhibition is shown here for carps experimentally exposed to the carbamate carbofuran. We also present data obtained on the AChE gene in the zebrafish Danio rerio and on molecular forms of AChE in Danio, Cyprinus carpio and Oncorhynchus mykiss. Contrary to what is observed in other vertebrates, Danio AChE gene does not contain H exon and only T subunits have been identified in these three species. Preliminary results of in situ hydridization of AChE messengers on embryos are also presented and the interest of plasmid micro-injection in the egg of Danio is discussed for the study of a possible function of AChE in morphogenesis at early stages of development.