Macroscopic ion channel currents (I) are a product of the channel open probability (Po ), the single channel current (i) and the number of channels present on the cell surface (N) at any given time (I=PoiN). Endocytosis has been shown to be one of the key determinants of cell surface channel density and the defects of this process have been linked to diseases relating to ion channel dysfunction. Chemiluminescence-based techniques provide a rapid method for the examination of the rates of endocytosis and steady-state cell surface density of ion channels and have previously been used to investigate the endocytosis of pancreatic ATP-sensitive potassium (KATP ) channels.
