Effects of isoflurane and xenon on Ba 2+ -currents mediated by N-type calcium channels † †Declaration of interest. Professor Franks is a board member of an Imperial College spin-out company, Protexeon Ltd, that is interested in developing clinical applications for medical gases, including xenon. Professor Franks is a paid consultant in this activity. In addition Air Products have funded work in the authors’ laboratories that bears on the actions of xenon as an anaesthetic and neuroprotectant. Air Products has a financial stake in Protexeon Ltd.