[Magnetoencephalographic observation of cortical spreading depression elicited by experimental focal brain ischemia in rats].
It has recently been reported that focal ischemia induced by occlusion of unilateral middle cerebral artery provoked direct current (DC) potential deflection in the cortical infarct rim. DC potential deflection is suggested to be one of the deteriorating factors for ischemic damage. We aimed to elucidate whether a direct current magnetoencephalography (MEG) can noninvasively record DC potential deflection in focal brain ischemia or not. Fourteen male Wistar rats were used for this study. After anesthesia with pentobarbital, rats were subjected to transcranial occlusion of left middle cerebral artery by electrocauterization. Three rats showed recurrent DC potential deflections, like cortical spreading depression (CSD). The direct current MEG deflections always followed DC potential obtained by electrically recorded electrocorticograms. Mean repetition interval of DC potentials was 574 +/- 178 (SD) seconds, and their mean amplitude was 1266 +/- 789 fT. Time course of DC potentials induced by focal ischemia resembles to CSD induced by KCl application to cerebral cortex. Our observation suggests that DC magnetoencephalography is one of the useful tools for non invasive recording direct current potential deflections which are impossible to be obtained by conventional EEG techniques, and that this method will be a powerful diagnostic tool for focal brain ischemia.
Takanashi
Y
Y
Department of Neurology and Gerontology, Kyoto Prefectural University of Medicine, Japan.
Chopp
M
M
Nakajima
K
K
D000818:Animals; D002343:Carotid Artery, Internal; D002540:Cerebral Cortex / Q000503:physiopathology*; D003250:Constriction; D004569:Electroencephalography; D002546:Ischemic Attack, Transient / Q000175:diagnosis* / Q000503:physiopathology; D015225:Magnetoencephalography / Q000379:methods; D008297:Male; D051381:Rats; D017208:Rats, Wistar