Résumé
Cholinesterase activity can be found in all kingdoms of living organism, yet cholinesterases involved in cholinergictransmission appeared only recently in the animal phylum [1]. The closest proteins homologous to thecholinesterases are the neuroligins. These proteins with an altered catalytic triad and no identified hydrolyticactivity have well-identified cell adhesion properties. Comparing evolution of the cholinesterases and neuroliginswith other proteins involved in synapse functioning may shed light on the common or divergent developmentalregulation events involved into the setting and maintenance of cholinergic transmission versus the balance betweeninhibitory and excitatory synapses. This comparison and its implications will be presented.