ASPECTS OF NEURAL PLASTICITY IN THE CENTRAL-NERVOUS-SYSTEM .6. STUDIES OF THE EFFECTS OF GANGLIOSIDES ON BRAIN METABOLIC LESIONS

The effects of gangliosides have been studied in two models of metabolic insult (insulin-induced hypoglycemia and transient forebrain ischemia) of the central nervous system. In the severe hypoglycemia experiments lactate extracellular fluid levels were evaluated by means of a microdialysis probe implanted in the frontoparietal cortex. Ganglioside GM1, given either peripherally (10 mg/kg, i.p.) or intracerebrally (2 x 10(?4) M, via the microdialysis probe) 2 h before insulin injection, was able to reduce the decay of the perfusate levels of lactate induced by the insulin injection. In the same animal model peripheral, but not central, administration of GM1 reduced the hypoglycemia-induced increase of cerebral blood flow and increased the survival time observed after the insulin injection. In the experiments on transient forebrain ischemia, a GM1 derivative, AGF2 (5 mg/kg/day, i.p.), was administered chronically, starting 5 days before or the day after the ischemic insult. With both treatment schedules a similar protective effect was observed in a neurological test battery and in the step-through latency in a passive avoidance test.