Figure 6.

Original recordings of elevations of intracellular Ca²⁺ concentrations by SPP and SPPC in cultured rat aortic smooth muscle cells. Intracellular Ca²⁺ concentrations were measured in Fura2-loaded cells pretreated with or without 100 ng ml⁻¹ PTX for 16 h. The arrows indicate time points of addition of SPP (1 μmol l⁻¹) or SPPC (10 μmol l⁻¹). SPP (A) and SPPC (C) rapidly and transiently elevated intracellular Ca²⁺ concentrations with a larger increase upon stimulation with SPP compared to SPPC. The effect of SPP and SPPC was strongly attenuated by PTX (B, D).