Abstracts

RATIONALE: The main purpose of this study was to evaluate the density of delta opioid receptors in neurosurgically obtained cortical (temporal and extratemporal) tissue of patients with idiopatic intractable epilepsy and epilepsy secondary to gliomas. Differences between the site of seizure onset (level 1 of Rasmussen) and surrounding areas involved in the spread and reverberation of epilepsy (level 2 of Rasmussen) were analyzed. METHODS: Cortical tissue from patients with glioma tumor without epilepsy (n=4) was used as control situation, whereas cortical epileptic tissue was obtained from 12 patients with intractable epilepsy. Rasmussen s levels were identified by transurgical electrocorticography and other preoperative image and electrophysiology procedures. Immediately after its resection, the tissue was frozen and then processed for quantitative in vitro receptor autoradiography using (3H)DPDPE as a delta opioid ligand. RESULTS: Examination of delta opioid receptor binding did not reveal significant differences between results from patients with idiopathic intractable epilepsy and epilepsy secondary to tumors. The delta opioid receptors detected in level 1 of Rasmussen (221?49 fmol/mg protein) were similar to those detected in control situation (236?13 fmol/mg protein). In contrast, reduced binding was found in level 2 of Rasmussen (167?2.4 fmol/mg protein; 30% reduction when compared with control group), an effect that was no associated with neuronal loss. CONCLUSIONS: Decreased delta opioid receptors in the areas involved in the spread and reverberation of epilepsy could be associated with inadequate opioid peptide inhibition that facilitates the ictal propagation from the epileptic focus to other brain areas. (Supported by CONACyT 31702-M).