Retardation of amygdala kindling by antagonism of NMD-aspartate and muscarinic cholinergic receptors: evidence for the summation of excitatory mechanisms in kindling

DL-2-amino-5-phosphonovaleric acid (APV), a specific antagonist of N-methyl-D-aspartate (NMDA) receptors, was administered alone and in combination with scopolamine (SCO), an antagonist of muscarinic cholinergic receptors, to different groups of rats undergoing electrical kindling of the amygdala. Both groups were significantly retarded in their rate of kindling during 15 drug sessions compared to controls, and the group receiving APV and SCO kindled significantly slower than the group receiving APV alone. These results indicate that both NMDA and muscarinic cholinergic receptors are involved in kindling of the amygdala, and implicate a mechanism involving the summation of excitatory neurotransmission in kindling of the amygdala.