Fig. 4.

In PMVECs, the AC10 cAMP pool is not potentiated by elevated intracellular calcium. A: PMVECs were loaded with the calcium indicator fura 2-AM in the presence of 2 mM extracellular calcium. Following the addition of 1 μM ionomycin at the 200-s time point, the ratios of the wavelengths of calcium-bound (340 nm) to -unbound (380 nm) for fura 2 fluorescence were recorded. EDTA (5 mM) was added to chelate calcium 20 min after the addition of ionomycin (n = 9). B: ionomycin did not potentiate the bicarbonate-induced, rolipram-sensitive cAMP pool even in the presence of rolipram at the 15-min time point. Individual experiments are performed in triplicate with at least n = 3 for each condition. Values are presented as means ± SE. NS, not significant.