PLCδ1PH-mRFP fluorescence in fibers expressing Ci-VSP. (A) Confocal images of a portion of a muscle fiber expressing Ci-VSP using the pIRES-EGFP plasmid and PLCδ1PH-mRFP. The image on the right shows the PLCδ1PH-mRFP fluorescence at higher magnification, and the graph below shows the fluorescence profile along the longitudinal axis of the highlighted rectangular region (yellow box). (B) Time course of change in PLCδ1PH-mRFP fluorescence averaged over a given area of the fiber while applying 5-s-long depolarizing pulses according to the protocol shown on top (closed circles); superimposed time course of change in PLCδ1PH-mRFP fluorescence measured subsequently over a nearby fiber area while no pulse was applied (open circles); synthetic trace generated from a two-exponential fit to the closed-circles record, using only the 20 first and 20 last values in the record for the fit (line). (C) Changes in fluorescence associated with the depolarizing pulse protocol after normalization by the record taken when no pulse was applied (closed circles); changes in fluorescence associated with the depolarizing-pulse protocol after normalization by the synthetic record (open circles).
