EFFECTS OF ANOXIA ON ENERGY-METABOLISM IN CRUCIAN CARP BRAIN-SLICES STUDIED WITH MICROCALORIMETRY

Crucian carp (Carassius carassius L.) is an exceptionally anoxia-toler ant vertebrate. To determine whether isolated crucian carp brain tissu e survives anoxia and whether it displays anoxic metabolic depression, heat production (using microcalorimetry), lactate production, ethanol production and the maintenance of ATP, ADP and AMP levels and energy charge were measured in telencephalic brain slices during anoxia. In r esponse to anoxia, heat output decreased by 37%, corresponding to a 31 % fall in ATP turnover rate. Adenylate phosphates and energy charge we re well maintained and no ethanol was produced during anoxia, It is co ncluded that crucian carp brain tissue has an intrinsic capacity to to lerate anoxia and that it responds to anoxia by depressing metabolic r ate and elevating the glycolytic rate, thereby maintaining ATP levels.