Brain Functional Localization Of Kidling Cats: Manganese Ion Enhances T1-Weighted MRI Study

Abstract

Purpose: Our previous studies have demonstrated that calcium overloading is involved in the epileptogenesis. Mn is handled in a manner similar to Ca in many biological systems and can act as an excellent MRI contrast agent, so our present study was performed to determine the encephalic region correlated to epileptogenesis by Mn-fMRI and further to determine the correlation of epilepsy and calcium overloading. Methods The cats were divided into two groups, the first group was divided into group A and B, A group was PTZ experimental group, B group was normal saline (NS) controlling group, The first group was used to EEG examination, the adult male cats were combined anesthetized with ketamine and chlorderazin, with intramuscular injected of PTZ (55mg/kg), the ethological and EEG changes were observed. The second group was divided into group A and B, group A was used to Mn-fMRI of the acute epileptic seizures, group B was used to Mn-fMRI at the time of 24 hours after the acute epileptic seizures were induced, group C was control group NS. The adult male cats were combined anesthesia with ketamine and chlorderazin; two femoral veins were taken one for Mncl2 infusion, the other for mannitol infusion. The cats were injected with PTZ intramuscular, and the changes were observed under TI-Weighted MRI. Signal enhanced encephalic regions were dislodged to be done. Results: The ratio of kindling cats was 80% with intramuscular injection of PTZ, the EEG were paroxysmal with spike-slow waves of high amplitude, the etiology and EEG of control group were normal. When the cats showed generalized tonic-clonic convulsive seizures, cerebral cortex showed diffusely signal enhancement, the enhancement rate of frontal-parietal-occipital lobe was 34.6; the enhancement rate of temporal lobe was 22.9, and they had significant difference compared to the control groups. The Mn-fMRI at the time of 24 hours after epileptic seizures attacked also showed signal enhancement on frontalparietal lobe. The neurons of enhanced encephalic regions show obvious degeneration and necrosis. Conclusion Cats can be succeeded to kindling by intramuscular PTZ (55mg/kg). Frontal-parietal lobe was the correlated encephalic regions of epilepsy, Mn-fMRI has important role on the localization and revealing pathogenesis of epileptic seizures.