ADENOSINE AND ADENOSINE-TRIPHOSPHATE DECREASE CA-45 UPTAKE BY SYNAPTOSOMES STIMULATED BY POTASSIUM

The action of adenosine and adenosine triphosphate on the uptake of 45Ca has been studied on the synaptosome-rich preparation from the rat cerebral cortex. The preparation was depolarized by high potassium. Adenosine (0.1-2mM) and adenosine triphosphate (0.2 mM) decreased the uptake of 45Ca. Adenosine triphosphate (1 mM) did not change significantly the uptake of 45Ca and adenosine triphosphate (2 mM) even increased it. These results indicate that the inhibitory effects of these substances on neurotransmission result from its inhibitory effects on the entry of calcium into the nerve endings. © 1979.