Early and transient increase of rat hippocampal blood-brain barrier permeability to amino acids during kainic acid-induced seizures.

The effects of kainic acid (KA) induced seizures on the permeability of hippocampal blood-brain barrier (BBB) to amino acids were investigated using a new method based on the combination of brain microdialysis of alpha-[3H]aminoisobutyric acid (AIB) and blood sampling. The transfer of AIB through the BBB was thus, for the first time, monitored in vivo in awake animals. KA administration i.v. produces a rapid and transient increase in hippocampal transfer of AIB after the beginning of seizures which is closely correlated to epileptic activity. The possible consequences of this increased transport of AIB from blood to brain are discussed in relation to previously reported transient augmentations of extracellular cerebral glutamate concentrations during KA-induced epilepsy.