A versatile chamber for microphysiologic studies with gas mixtures under high pressure

A pressure chamber, designed for microelectrode recordings in isolated tissues or organs an capable of withstanding pressures up to 200 bar, is described. The versatility of the vessel allows a wide variety of experimental configurations and several types of studies. It features a complete access, easy visibility, interchangeable tissue bath and micromanipulator modules, as continuous perfusion and temperature control of the preparation under pressure. The ability to move micropipettes in 1-micron steps allows single unit recording on a variety of in vitro preparations at normal or elevated gas pressures. Successful physiologic tests, using the hippocampal slice preparation, are described. The results testify to the reliability of the system and to the usefulness of this in vitro model to study the gas pressure effects on isolated networks of mammalian CNS.