Glutamate stimulation of 45Ca uptake by rat striatal synaptosomes

The effects of acidic excitatory amino acids and 60 mM K+ on 45Ca uptake by synaptosomes prepared from rat striatum were examined. Both glutamic acid and 60 mM K+ significantly stimulated the uptake of 45Ca and these effects were antagonized by 30 mM Mg2+ and 0.5 mM La3+ but not by 5 microM tetrodotoxin. Neither kainic acid nor N-methyl-D,L-aspartic acid significantly affected the uptake of 45Ca. The results suggest that glutamate may activate a presynaptic receptor that is directly linked to calcium channels.