Regional cerebral energy metabolism in bicuculline induced seizures.

In order to assess the early regional changes in energy metabolism in bicuculline induced seizures, mice were injected and sacrificed before the onset of overt seizure activity, and shortly after clonic-tonic seizures began. The energy metabolites glucose, ATP, and phosphocreatine were measured in layers of the motor cortex and the cerebellar vermis. Results showed minimal metabolite changes in the cerebellum, whereas changes in energy metabolism in the motor cortex were largely localized to the layers containing pyramidal cells. These results are in agreement with previous studies showing a relative sparing of the cerebellum, and suggest early cortical changes occur in pyramidal cells.

Pentylenetetrazole-induced changes in cerebral energy metabolism in Tupaia glis.

The convulsant pentylenetetrazole was administered to the lower primate, the tree shrew. Shortly after the onset of seizures, the animals were killed using a microwave device at 25 Kw and 915 MHz. The energy metabolites glycogen, glucose, ATP, and phosphocreatine were measured in five layers of the cerebral cortex and three layers of the cerebellum. Results showed that, as compared with controls, seizing animals had decreased energy metabolites selective to certain layers. Glucose was decreased in all cortical layers, but only in the granular layer of the cerebellum. Phosphocreatine was decreased in the outer small pyramidal layer and the polymorphous layer of the cortex but was unchanged in the cerebellum. ATP was decreased only in the outer small polymorphous layer of the cortex. These changes are consistent with the concept that selective changes may occur during seizures and that these changes are localized to layers that contain pyramidal cells. Examination of whole cortex may mask more subtle regional changes.

Status epilepticus-induced changes in primate cortical energy metabolism.

The objective of this study was to evaluate changes in cortical energy metabolism in experimentally induced seizures in the primate. Cynamologus fascicularis monkeys were anesthetized, and a craniotomy was performed. Small samples from the motor cortex were removed for measurement of energy metabolites just prior to intravenous bicuculline infusion (0.6 mg/kg), 20 min after the onset of seizures, and 2 h after the second sample. Samples were also taken for electron microscopy. Results showed decreased phosphocreatine values 20 min after the onset of seizures, whereas ATP levels were normal. Two hours after the onset of seizures, phosphocreatine had returned to normal, but ATP levels were below normal. Examination of tissue by electron microscopy showed evidence of cell damage 2 h, 20 min after the onset of seizures. These findings are consistent with the concept that sustained seizures may lead to irreversible cell damage and that alterations in energy metabolism may contribute to the cell death.