We here demonstrated the expression of 4 (P2Y1,4,6,11) purinoceptors mRNAs coupled to Gq protein. The extracellular ATP, UTP, ADP and UDP caused a transient [Ca2+]i peak followed by a sustained lower phase. Removal of extracellular Ca2+ decreased the initial transient and abolished the plateau phase. Ca2+ signal was blocked by the inhibitor of PLCβ, U73122. Through experiments of fluorescence quenching, it was seen that nucleotides increased plasmamembrane Ca2+ permeability. These results indicate that [Ca2+]i increase was due to activation of P2Y receptors exclusively and that Ca2+ is released from intracellular stores and also enters from the extracellular liquid. We also investigated the effects of purinoceptors on cell proliferation. UTP, ATP and UDP had no significant effects, while ADP causes a drastic cell proliferation decrease in a dose- and time-dependent manner. In conclusion, these results indicate that the expressed purinergic receptors act via PLC activation and that ADP may have a therapeutic potential in MM.