Glutamate-evoked release of adenosine 5’ -triphosphate causing an increase in intracellular calcium in hippocampal neurons

ATP evoked an increase in intracellular Ca²⁺ concentration ([Ca]_i) in hippocampal neurones in the presence of tetrodotoxin (TTX, 3 μM), hexamethonium (C6,100 μM), D-2-amino-phosphonovalerate (APV, 100 μM), 6- cyano-7-nitro quinoxalline-2,3-dione (CNQX, 30 μM), bicuculline (10 μM) and cadmium (Cd²⁺, 300 μM). The increase was blocked by suramin (100 fiM), a P₂-purinocep- tor blocker. These results suggest that ATP evokes an increase in [Ca]_; through P₂-purinoceptor. As a result of measuring [Ca], in multiple cells simultaneously, it was suggested that glutamatergic neurones connect with purinergic neurones and glutamate (10 /xM) stimulated the release of ATP causing an increase in [Ca]_; in postsyn- aptic neurones.