Dixon C J, Cobbold P H, Green A K
Department of Human Anatomy and Cell Biology, University of Liverpool, U.K.
Biochem J. 1995 Jul 1;309 ( Pt 1)(Pt 1):145-9. doi: 10.1042/bj3090145.
We have previously described differences in the oscillatory responses of cytosolic free Ca2+ concentration ([Ca2+]i) in hepatocytes to ADP and ATP, which we have interpreted as evidence that these two nucleotides are acting at distinct receptors. We show here that ADP- and ATP-induced oscillations are differentially sensitive to application of the phorbol ester 4 beta-phorbol 12,13-dibutyrate (PDB). ADP-induced [Ca2+]i oscillations are abolished by low concentrations of PDB (5-10 nM), whereas ATP-induced oscillations of long duration are refractory to PDB, even at greatly elevated concentrations (100 nM). The data illustrate a further difference in the actions of ADP and ATP, strengthening the argument that these agonists are not acting at the same receptor on rat hepatocytes.
我们之前曾描述过肝细胞中胞质游离钙离子浓度（[Ca2+]i）对ADP和ATP的振荡反应存在差异，我们将此解释为这两种核苷酸作用于不同受体的证据。我们在此表明，ADP和ATP诱导的振荡对佛波酯4β-佛波醇12,13-二丁酸酯（PDB）的应用具有不同的敏感性。低浓度的PDB（5 - 10 nM）可消除ADP诱导的[Ca2+]i振荡，而ATP诱导的长时间振荡对PDB不敏感，即使在浓度大幅升高（100 nM）时也是如此。这些数据说明了ADP和ATP作用的进一步差异，强化了这些激动剂并非作用于大鼠肝细胞同一受体的观点。
