Oxygen tension clamp around single neurons in vitro : a computerized method for studies on O2 deprivation

This report presents a novel computerized oxygen tension clamp for use with single neurons. One main objective for developing such a system is to be able to study the intrinsic response of single neurons to graded hypoxia. The device described in this paper is comprised of three major subsystems: (1) an oxygen monitoring subsystem, (2) a motorized perfusion subsystem and (3) a computer subsystem for data acquisition and control. The clamp uses an oxygen scavenger (sodium hydrosulfite) to decrease O2 availability. The system has many advantageous features: (a) studies on hypoxia can be carried out without using chemical metabolic inhibitors to simulate hypoxia; (b) precise control of the O2 level around a given cell is feasible for extended periods of time; (c) rapid and accurate changes in the O2 level around a cell can be made because the O2 level is continuously monitored and adjusted by a computer; (d) other cells outside of the immediate vicinity of the cell being studied are not subjected to hypoxic exposures; and (e) the system is inexpensively built around readily available components.