Figure 5.

cADPR-sensitivity of the upper and lower phases obtained by aqueous two phase partitioning of cauliflower microsomes. Loading of Ca²⁺ into vesicles from the upper (▪) and lower (○) phases was terminated by addition of FCCP (10 μm) and Na₃VO₄ (200 μm). Curves are standardized to this point (100% Ca²⁺ accumulation = 31.9 ± 1.2 [▪] and 14.4 ± 0.9 nmol mg⁻¹ [○]). cADPR (1 μm) was subsequently added and three aliquots removed to estimate Ca²⁺ remaining in the vesicles by measuring radioactivity content. Data are the means ± se of three experiments.