[22Na metabolism in slices of rat hippocampus]

Three different compartments of Na were distinguished in the rat hippocampal cuts: 71, 24, and 5% of total tissue Na. Their half-times for Na efflux were 9.8, 27, and 104 sec. resp. The transport flux of Na was about 2 moles per kg tissue per hour. Ouabain when added to incubation medium did not diminish the Na efflux value while diminishing about 5-fold the "energy cost of transport". The Na transport from cells in hippocampal tissue took 60--76% of total energy given by respiration