Non-SG fusion in whole-cell recording is wortmannin/adenosine insensitive. (A) Typical whole-cell capacitance records and composite statistics for RBL cells during cytoplasmic infusion of 200 μM Ca with control cytoplasmic solution (top) and with 5 μM wortmannin and 0.5 mM adenosine (bottom). Differences are not significant. (B) Exchange current densities (top) and capacitance responses (bottom) for BHK cells in which membrane fusion was activated by outward Na/Ca exchange current with control cytoplasmic solution (left bar graph), with 0.5 mM adenosine (middle bar graph), and with 5 μM wortmannin and 0.5 mM adenosine (right bar graph) are shown.