Extracellular ATP-stimulated increase of cytosolic cAMP in HL-60 cells.

Extracellular ATP increases intracellular Ca2+ concentration ([Ca2+]i) through activation of P2U purinoceptors in HL-60 cells. We found that extracellular ATP also increased the intracellular cAMP level in undifferentiated HL-60 cells. ATP and the hydrolysis-resistant ATP analogue adenosine 5'-O-(3-thiotriphosphate) triggered cAMP production in a concentration-dependent manner. The effects of ATP analogues on the [Ca2+]i elevation was distinguished from their effects on cAMP generation. Reactive Blue 2, the antagonist of P2 purinoceptors, inhibited ATP-induced cAMP generation in a concentration-dependent manner without inhibiting Ca2+ mobilization. The results suggest that a distinct P2 purinoceptor, one different from P2U, is linked to adenylyl cyclase in HL-60 cells.