Studies of Changes in Cytoplasmic pH and Membrane Potential Using Flow Cytometry

Cell activation means the changes in functional and metabolic activity that occur when specific signalling pathways, either alone or in combination, respond to engagement of signal-transducing molecules. These changes include ion fluxes that may result in net alterations of cytoplasmic ion concentration and thereby affect enzyme activation or inhibition, or that may not actually change ion concentration, but may nonetheless cause physical or chemical changes, such as membrane depolarization. Modifications in assembly of the cytoskeleton, secretion of new bioactive metabolites, and expression of stored or masked molecules frequently ensue.