In this study, we examined the response of
glioma C6 cells to 2',3'-O-(4-benzoylbenzoyl)-ATP (
BzATP) and showed that the
BzATP-induced calcium signaling does not involve the P2X(7) receptor activity. We show here that in the absence of extracellular Ca(2+),
BzATP-generated increase in [Ca(2+)](i)via Ca(2+) release from intracellular stores. In the presence of
calcium ions,
BzATP established a biphasic Ca(2+) response, in a manner typical for P2Y receptors.
Brilliant Blue G, a selective antagonist of the rat P2X(7) receptor, did not reduce any of the two components of the Ca(2+) response elicited by
BzATP.
Periodate-oxidized ATP blocked not only
BzATP- but also
UTP-induced Ca(2+) elevation. Moreover,
BzATP did not open large transmembrane pores. What is more, a cross-desensitization between
UTP and
BzATP occurred, which clearly shows that in
glioma C6 cells
BzATP activates most likely the P2Y(2) but not the P2X(7) receptors.