Fig. 5.

Ca²⁺ is required for nucleotide-induced DNA synthesis in VVEC. Growth-arrested VVEC (72 h in serum-free DMEM) were preincubated with or without BAPTA-AM (10 and 30 μM) for 30 min and then stimulated with ATP (100 μM) in the presence of 0.125 μCi of [³H]thymidine for 24 h. Incorporated radioactivity was measured in total cell lysates using a beta counter. Data are means ± SE from 4 experiments conducted on 2 distinct VVEC populations. *P < 0.001 vs. nonstimulated control. #P < 0.001 vs. ATP-stimulated cells.