SUPPRESSION OF CORTICAL EPILEPTIC ACTIVITY IN RATS AND HUMANS BY CARBON DIOXIDE
Abstract number :
3.088
Submission category :
1. Translational Research
Year :
2008
Submission ID :
8547
Source :
www.aesnet.org
Presentation date :
12/5/2008 12:00:00 AM
Published date :
Dec 4, 2008, 06:00 AM
Authors :
Else Tolner, J. Otáhal, P. Hassinen, G. Tsenov, E. Gaily, L. Metsähonkala, S. Schuchmann, H. Kubová, S. Vanhatalo and K. Kaila
Rationale: We recently showed that experimental febrile seizures in neonatal rats are triggered by a respiratory alkalosis, and blocked by 5% CO2 applied in the ambient air (Schuchmann et al., Nat Med 2006; 12: 817-823). Since changes in acid-base balance are known to have significant effects on neuronal excitability also in the mature brain, we set out to study the effects of CO2 on cortical epileptic activity both in adult rats and humans. Methods: A rat model for myoclonic seizures was used in which electrical stimulation of the sensorimotor cortex elicits bilateral epileptiform afterdischarges in the EEG that are paralleled by clonic seizures of face and forelimb muscles. Studies in humans were performed on epileptic patients undergoing video-EEG monitoring for prospective epilepsy surgery. Gas mixtures consisted of 5% or 10% CO2 in air in rats, and 5% CO2 in oxygen in humans (medical carbogen). They were applied for 3 minutes before stimulation in rats, and in humans for a period of 20-30 seconds shortly after the start of generalized seizure activity. Results: In rats, 10% CO2 application dramatically reduced or completely blocked the stimulation-evoked epileptiform afterdischarges. In the epileptic patients, 5% CO2 application significantly reduced the duration of generalized seizures. Conclusions: Our data suggest that application of CO2 may be effective in the acute treatment of epileptic seizures not only in neonates but also in adults.
Translational Research