Alterations in cholecystokinin peptide and mRNA in actively epileptic human temporal cortical foci

The cholecystokinin (CCK) content of temporal cortex, obtained at neurosurgery from 22 patients with temporal lobe epilepsy, was measured by a specific radioimmunoassay. Tissue immunoreactivity was identified as authentic sulfated CCK-8 by reverse phase high performance liquid chromatography. Several samples were also analyzed by RNA blot hybridization for preproCCK mRNA. The CCK content of cortical tissue from which active epileptic spiking was recorded at the time of surgery (11 patients) was significantly decreased (20% lower) in comparison to tissue samples from a second group of 11 patients in whom the lateral temporal cortex was electrographically free of epileptiform spikes. These data suggest that the decrease may be due to continuous release of CCK as a result of abnormal neuronal firing within the focus. This hypothesis may also be consistent with our observation of a slight increase (67%) in preproCCK mRNA in the actively spiking group compared to the non-spiking cortical samples.