All Organisms Can Be Anesthetized, but There's No Point?

Because of their interest in medicine, most studies on anesthesia have historically focused on the nervous systems of animals. This has often led to the neglect of the fact that all life forms have the potential to be anesthetized. Anesthetics target proteins, such as four-domain voltage-dependent Na⁺/Ca²⁺ channels (4D-NaV/CaV) and glutamate receptor channels (iGluR/GLR), which have homologs in a wide variety of species. These proteins originate from ancestral channels that predate eukaryotes in the evolutionary process. These channels are evidently so essential for living cells that they are under strong selective pressure. Consequently, the susceptibility of most living organisms to anesthesia has been interpreted as a result of natural selection. Here, we propose an alternative hypothesis that this susceptibility is attributable to an intrinsic weakness in living cells.