Fig. 5.

Effect of intracellular Ca²⁺ chelation and Ca²⁺-transport inhibitors on ⁴⁵Ca²⁺ uptake. A: effect of BAPTA-AM and dimethyl BAPTA-AM. Quiescent cells were exposed to ⁴⁵Ca²⁺ (1 μCi/well, 6.7 Ci/mol CaCl₂) in the presence or absence of 10 μM of BAPTA-AM or dimethyl BAPTA-AM for 1 to 20 min, respectively. The cells were washed, and the remaining ⁴⁵Ca²⁺ in each well was determined by scintillation counting techniques. Significance was determined between control and BAPTA-AM or dimethyl BAPTA-AM. *P < 0.05, **P < 0.01. B: effect of transport inhibitors on dimethyl BAPTA-AM-stimulated ⁴⁵Ca²⁺ uptake. The data are expressed relative to uptake by unstimulated cells. Cells were serum starved overnight and pretreated with 10 μM SKF-96365 or 10 μM nifedipine for 20 min before exposure to 10 μM dimethyl BAPTA-AM for 20 min. ⁴⁵Ca²⁺ uptake was measured as described A. The data are from 2 to 5 independent experiments.