Isoflurane does not aggregate inside POPC bilayers at high pressure: Implications for pressure reversal of general anaesthesia

Abstract : We placed isoflurane, a general anaesthetic, inside palmitoyloleoylphosphatidylcholine (POPC) bilay-ers at clinical concentration, and performed molecular dynamics simulations at atmospheric and raised pressures, using two different thermodynamic ensembles. We also performed a simulation of this system with isoflurane at ten times the clinical concentration. We found that isoflurane did not aggregate inside POPC membranes at 20 MPa, nor at 40 MPa. The implications of these findings for pressure reversal is discussed, in light of the high-pressure neurological syndrome.