Different actions of sevoflurane and propofol on central nicotinic receptors may explain differences in hypnotic antagonism by cholinesterase inhibitors.

Although there is considerable uncertainty about the physiological roles that nicotinic acetylcholine receptors (nAChRs) play in the central nervous system, their extraordinary sensitivity to general anaesthetics, particularly inhalational agents, suggests they may mediate some of the effects of general anaesthetics at surgical, or even subanaesthetic, concentrations. Sevoflurane reduces the binding of nicotinic receptor agonists, at concentrations at and above those required for anaesthesia. Propofol also exerts an inhibitory effect on these nicotinic receptors, but only at high concentrations. Current practice is to employ a peripherally-acting anticholinesterase drug to antagonize neuromuscular block. Administration of a centrally acting agent for this purpose could potentially increase the risk of intraoperative awareness.