With regional acetate exposure to activate a local NHE-driven Na(+)-influx, DNa was found to be sufficiently fast (680 µm(2)/s) for transmitting the pH-systolic Ca(2+) interaction over long distances.



Fortran
Cytoplasmic [Na(+)] ([Na(+)]i) was imaged using SBFI. 
SBFI
The systolic [Ca(2+)] response correlated with a rise in [Na(+)]i and sarcoplasmic reticulum Ca(2+) load, and was blocked by the NHE1 inhibitor cariporide (CO₂/HCO₃(-)-free media).  Exposure of one half of a myocyte to acetate using dual microperfusion (CO₂/HCO₃(-)-free media) raised diastolic [Ca(2+)] locally in the acidified region. 
CO₂/HCO₃(-)-free media