Phosphorylation of brain (NA+,K+)-ATPase alpha catalytic subimits in normal and epileptic cerebral cortex: II. Partial seizures in human epilepsy
✍ Scribed by Dr. Daniel Guillaume; T. Grisar; A. V. Delgado-Escueta; J. Laschet; M. Bureau-Heeren
- Publisher
- John Wiley and Sons
- Year
- 1991
- Tongue
- English
- Weight
- 624 KB
- Volume
- 29
- Category
- Article
- ISSN
- 0360-4012
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✦ Synopsis
We examined the activity and phosphorylation level of (Na+ ,K+)-ATPase (E.C. 3.6.1.3) partially purified from normal and epileptic human cortices. Control patients (n = 11) were operated on for a nonepileptogenic deep brain lesion, while epileptic patients (n = 10) were operated on for temporal or frontal originating partial seizures, resistant to medications or secondary to evolutive brain tumors. No differences in the specific activity of microsomal (Na+ ,K+)-ATPase were observed between the two groups of patients. After partial purification of the enzyme followed by SDS-polyacrylamide gel electrophoresis, (Na+ ,K+)-ATPase catalytic subunit had a decreased affinity for K+ in human epileptic cortex and lost its sensitivity to phenytoin dephosphorylation. Indirect evidence suggests that those abnormalities of (Na+ ,K+ )-ATPase in human epileptic cortex hold preferentially true for the alpha( -) enzymatic subunit. Those results indicate that, in human epileptic cortex, (Na+,K+)-ATPase and most probably its glial subtype is altered in its K + regulation and phenytoin sensitivity and could be responsible for ictal transformation and seizure spread.