Development of Susceptibility to Audiogenic Seizures following Cardiac Arrest Cerebral Ischemia in Rats

Abstract

Summary: Susceptibility to aUdiogenic seizures (AGS) was investigated in Sprague-Dawley rats subjected to cardiac arrest cerebral ischemia (CAC!), produced by compression of the major cardiac vessels. The onset of AGS was regularly observed 1 day after CACI of >5 min duration. The duration of postischemic susceptibility to AGS was directly related to the density of cerebral isch emia, with 50% of more severely ischemic animals still showing AGS susceptibility 8 weeks after CAC!. Lesion ing of the inferior colliculi (IC) abolished the onset of AGS; no such effect was observed after lesioning the me dial geniculate (MG), Glutamic acid decarboxylase (GAD) immunochemistry revealed �50% loss of GAD-

Occurrence of spontaneous and audiogenic seizures following global brain ischaemia due to cardiac arrest

“…Following that, the animals began to feed themselves and became restless. All animals after 10-minute cardiac arrest were alert and had no motor deficits at one day of survival, which is in accordance with other data [7,8]. As already shown, the rats' survival up to one month after reanimation did not exhibit any neurological or somatic deficits during the whole period of observation [8].…”

“…In clinical conditions, the appearance of seizures following cardiac arrest seems a predictor of poor outcome [9,29]. In our study, regular onset of audiogenic seizures was noted one day after cardiac arrest, which is in accordance with the observations by Kawai et al [7]. In our model, audiogenic seizures occured in the first two weeks of survival after acute transient global brain ischaemia, and after a particular period of time completely disappeared.…”

“…After cardiac arrest the rats (n = 50) survived for one month. Audiogenic seizures were triggered by using the rattling sound of keys (sound intensity 90-100 dB, frequency > 4,000 Hz), according to Kawai et al [7]. The sound stimulus was set until rats started to have seizures.…”

“…Female Wistar rats were used (150-170 g, 3 months old). In animals under anaesthesia [7], a blunt-ended, hooklike, metal probe with the distal end bent at 90° was placed inside the rats' chest cavity after midline skin incision [16]. The hook was inserted through the right parasternal line and third intercostal space into the mediastinum.…”

“…Experimental data indicate that cardiac arrest induces a susceptibility to audiogenic seizures in previously unsusceptible rats [7]. In view of the importance of cardiac arrest in human and its increasing occurrence in the world, as well as its frequent association with seizures, an experimental cardiac arrest model was used in the present investigations.…”