Fig. 7.

Lack of effect of PPTN at the P2Y₁₂-R and P2Y₁₃-R. (A) Forskolin (30 μM)–stimulated cyclic AMP accumulation was quantified in P2Y₁₂-CHO cells in the presence of the indicated concentrations of PPTN in the absence (open red circle) or presence (closed red circle) of 1 μM 2MeSADP. The results are the mean of triplicate determinations and are representative of results of at least three different experiments for each receptor. Typical values for basal and forskolin-stimulated [³H]cyclic AMP accumulation in P2Y₁₂-CHO cells were approximately 700 and 4000 cpm, respectively. Data from Fig. 4 were replotted (dotted blue line) to provide a comparative illustration of the concentration-dependent effects of PPTN for antagonizing the effect of 316 nM UDP-glucose at the P2Y₁₄-R. (B) Agonist-stimulated [³H]inositol phosphate accumulation was quantified in the presence of the indicated concentrations of PPTN in the absence (open symbols) or presence (closed symbols) of agonists in COS-7 cells transfected with expression vectors for Gα_q/i and the human P2Y₁₃-R (green) or P2Y₁₄-R (blue). The agonists used were 3 μM ADP and 1 μM UDP-glucose for the P2Y₁₃-R and P2Y₁₄-R, respectively. The results are the mean of triplicate determinations and are representative of results of at least three different experiments for each receptor.