Effects of Na+ and other monovalent cations on Ca-efflux from synaptosomes.

Effects of monovalent cations on Ca-efflux were examined in rat brain cortex slices, synaptosomes and synaptic plasma membranes. Effluxes of 45Ca from brain slices and synaptosomes were stimulated by Na+ in medium and the effects of Na+ on the 45Ca-effluxes disappeared at low temperature. Furthermore, we observed that Rb+ had more effect than Na+ on 45Ca-efflux from the synaptosomes, while Li+ had less effect.