CHANGES IN CHOLECYSTOKININ MESSENGER-RNA EXPRESSION AFTER AMYGDALA-KINDLED SEIZURES - AN IN-SITU HYBRIDIZATION STUDY

Cholecystokinin (CCK) can be a potent anticonvulsant neuropeptide in c ertain seizure models. Therefore, we examined whether seizures produce d by electrical kindling of the amygdala or electroconvulsive seizures (ECS) would affect the expression of CCK mRNA in rat brain. Following a single kindled seizure, CCK mRNA expression was decreased about 20- 58% in the amygdala. In contrast, after multiple consecutive kindled s eizures, CCK mRNA expression was increased in the amygdala, cerebral c ortex, CA1 pyramidal cell layer of the hippocampus and dentate hilus. A single ECS produced no effect on CCK mRNA expression, but multiple E CS increased expression in the interneurons of the hippocampus 24 h af ter the last seizure. Since seizures produced by ECS can be anticonvul sant to further ECS or kindled seizures, the CCK increases in the hipp ocampus may represent a compensatory anticonvulsant adaptation observe d in both models. Overall, the kindling-induced alterations in CCK exp ression appear to be more complex involving multiple brain regions and distinct temporal properties.