Cerebral and cerebellar metabolic changes induced by drugs during the recovery period after profound hypoglycemia.

On rat cerebral and cerebellar cortex, severe hypoglycemia with isoelectric EEG induced extensive deterioration of the energy state and gross alteration of amino acid contents. During recovery, tissue glucose concentration returned to normal, while the rate of glycogen synthesis was slow, both lactate and pyruvate concentrations increasing to above normal. In the recovery period, the ATP concentration increased but the adenine nucleotide pool remained reduced, even if the ADP and AMP contents were close to normal. Phosphocreatine was restored to normal concentrations with reciprocal changes in creatine content. During recovery there was a rise in glutamate and glutamine concentrations, gamma-aminobutyrate content returning to normal value. Ammonia and aspartate decreased below normal, while alanine increased above normal. The effect of some drugs on the post-hypoglycemic recovery was tested: (a) Ergot alkaloids (dihydroergocristine, dihydroergocriptine, dihydroergocornine); (b) Vinca minor alkaloids (vincamine TPS, (--)-eburnamonine); (c) Rauwolfia serpentina alkaloids (reserpine, raubasine); (d) synthetic agent (piracetam). During the post-hypoglycemic recovery, these different agents exhibited different, or even contrasting, interferences on glycolytic metabolites, amino acids and energy-rich phosphates. The metabolic alterations in the cerebellar cortex were qualitatively of the same character of those in neocortex. However the metabolic alterations were less extensive and more sensitive to drug action.