Explaining general anesthesia: a two-step hypothesis linking sleep circuits and the synaptic release machinery.
Several general anesthetics produce their sedative effect by activating endogenous sleep pathways. We propose that general anesthesia is a two-step process targeting sleep circuits at low doses, and synaptic release mechanisms across the entire brain at the higher doses required for surgery. Our hypothesis synthesizes data from a variety of model systems, some which require sleep (e.g. rodents and adult flies) and others that probably do not sleep (e.g. adult nematodes and cultured cell lines). Non-sleeping systems can be made insensitive (or hypersensitive) to some anesthetics by modifying a single pre-synaptic protein, syntaxin1A. This suggests that the synaptic release machinery, centered on the highly conserved SNARE complex, is an important target of general anesthetics in all animals. A careful consideration of SNARE architecture uncovers a potential mechanism for general anesthesia, which may be the primary target in animals that do not sleep, but a secondary target in animals that sleep.
Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia.
Bruno
B
van Swinderen
Benjamin
B
Kottler
D000768:Anesthesia, General; D018681:Anesthetics, General / Q000494:pharmacology*; D000818:Animals; D004195:Disease Models, Animal; D004330:Drosophila / Q000502:physiology; D006801:Humans; D012377:Rodentia; D050600:SNARE Proteins / Q000378:metabolism*; D012890:Sleep / Q000187:drug effects* / Q000502:physiology*; D013569:Synapses / Q000187:drug effects* / Q000502:physiology; D050827:Syntaxin 1 / Q000378:metabolism*; D014474:Unconsciousness
D018681:Anesthetics, General; D050600:SNARE Proteins; D050827:Syntaxin 1
Caenorhabditis elegans; Drosophila; SNARE; general anesthesia; neuroscience; sleep; syntaxin