Ouabain-induced Seizures in Rats: Regional and Subcellular Localization of 3H-Ouabain Associated with Na+–K+-ATPase in Brain

Abstract

Previous observations on clonic and tonic seizures in rats induced by intraventricular injections of ouabain, Zn²⁺, or Cu²⁺ have been expanded and confirmed. Tritiated ouabain was injected intraventricularly to rats and its regional distribution studied in the brain. The hippocampus and hypothalamus were found to be the regions with highest accumulation of radioactivity. This was supported by the in vitro finding that synaptosomes from both these regions demonstrate the highest uptake of the labelled ouabain. Subcellular fractionation experiments following in vivo injection of ³H-ouabain revealed that maximal radioactivity is associated with synaptosomal membrane fractions rich in Na⁺–K⁺-ATPase.