GLUTAMATE RELEASE IN EXPERIMENTAL-ISCHEMIA OF THE RETINA - AN APPROACH USING MICRODIALYSIS

A rabbit eve model of neural ischaemia is described that uses an increased pressure in the anterior eve chamber to block the capillary supply to the retina. A microdialysis probe placed verv close to the retinal surface was used to monitor release of amino acids during ischaemia. A large (two- to threefold) increase in the release of glutamate and O-phosphoserine (twofold), but not of six other amino acids monitored, occurred during initial ischaemia. During reperfusion after release of intraocular pressure, much larger (five- to 10-fold) increases in the release of these amino acids were observed. Parallel ischaemia retinal tissue damage was observed. This damage was prevented by ketamine applied locally via a superfusion needle, suggesting that glutamate released during ischaemia, and particularly during reperfusion, was responsible for cell death.