[Anaesthesia, a process common to all living organisms]

Because of their interest in medicine, most studies of anaesthesia focus on the nervous system of metazoans, and the fact that any life form can be anaesthetised is often underlooked. If electrical signalling is an essential phenomenon for the success of animals, it appears to be widespread beyond metazoans. Indeed, anaesthesia targets Na⁺/Ca²⁺ voltage-gated channels that exist in a wide variety of species and originate from ancestral channels that predate eukaryotes in the course of evolution. The fact that the anaesthetic capacity that leads to loss of sensitivity is common to all phyla may lead to two hypotheses: to be investigated is the evolutionary maintenance of the ability to be anaesthetised due to an adaptive advantage or to a simple intrinsic defect in ion channels? The study of anaesthesia in organisms phylogenetically distant from animals opens up promising prospects for the discovery of new anaesthetic treatments. Moreover, it should also lead to a better understanding of a still poorly understood phenomenon that yet unifies all living organisms. We hope that this new understanding of the unity of life will help humans to assume their responsibilities towards all species, at a time when we are threatening biodiversity with mass extinction.