Combined Calcium Fluorescence Recording with Ionic Currents in Contractile Cells

Measurement of calcium (Ca²⁺ ) fluorescence in conjunction with ionic currents is of particular importance in contractile cells, such as cardiac ventricular myocytes and vascular smooth muscle. The interplay between membrane potential and intracellular calcium ([Ca²⁺ ]_i ) is fundamental to the regulation of contractile function and cell signalling. Here the loading of cells either with an esterified fluorescence indicator prior to patch clamp recording, or dye loading via the patch pipette with “free” indicator, is described to allow simultaneous measurement of fluorescence and electrical signals.