PREPARATIVE METHODS FOR BRAIN-SLICES - A DISCUSSION

Criteria for slice health and factors that affect slice health were di scussed by many of the participants in the conference. In addition to the standard parameters of slice health (energy metabolism, morphology , electrophysiological responsiveness) more subtle but possibly equall y important manifestations of slice health were discussed. These inclu ded protein synthesis, and more subtle changes, of which we are becomi ng increasingly aware. The latter include synthesis of stress-related proteins, altered levels of phosphorylation, altered levels of proteol ysis. These last were only touched on, but it is becoming apparent the y do in fact constitute important manifestations of differences betwee n the slice preparation and the in vivo tissue. They may well lead to quite different responses in slices from those that occur in vivo. Whi le many ways of optimizing slice wellness were discussed, there was a fair consensus that certain adjustments will optimize the most widely measured aspects of cell function. These include the following, wherev er possible. Use of young animals, use of the interface chamber, prepa ring slices with the vibratome, pre-treating animals with ice-cold car diac perfusion before sacrificing, using pre-incubation media which re duce NMDA receptor activation, free radical formation and cell swellin g. When possible these treatments should perhaps be continued into the normal incubation. This being said, many viewpoints were actually exp ressed in the Discussion, and it should be read to get a feel for the usefulness of the different approaches.