Kindling of full limbic seizures by repeated microinjections of excitatory amino acids into the rat amygdala.

Fully developed limbic seizures were kindled by repeated (every second day) microinjections of an L-glutamate plus L-aspartate (Glu/Asp) mixture (1:3 ratio; 1.5 mumol total dose). Glu alone (1.5 mumol) or Asp alone (1.5 mumol), into the rat amygdala. This excitatory amino acid (EAA)-induced kindling was durable, persisting for at least several months, and showed strong positive transfer to electrical kindling. Fully EAA kindled seizures were inhibited by focally applied NMDA-receptor antagonists. EAA kindling and electrical kindling are shown to have many similar properties. This strongly suggests that they may also have neurochemical mechanisms in common. These results further highlight the important role of EAAs in basic mechanisms involved in the generation and expression of epilepsy.