[Metabolism of 22Na in the rat corpus callosum]

The kinetic parameters of 22Na+ exchange were measured with improved compartmental analysis in slices of rat corpus callosum. Three distinct Na compartments were found: 45, 38 and 15% of the total Na+, having T1/2 for efflux 7.3; 43.5 and 119 s, resp. Transmembrane Na flux was 2.4 M/g/hr. The obtained kinetic parameters were compared to those in neocortex and hippocampus.