This brief review has tried to shed some light on the mechanisms and significance of the changes in membrane potential and in ionic fluxes occurring in B-cells upon glucose stimulation. There is now strong evidence that, under physiological conditions at least, these electrical events-and the underlying modifications of ionic permeabilities and fluxes — play a causal role in the stimulation of insulin release. It also seems clear that certain accompanying ionic fluxes have no direct stimulatory role, but may be important in maintaining cellular homeostasis. Recent experimental evidence has also shown that the electrical activity in B-cells is not an all-or-none stereotypic response. Not only can its intensity be adjusted to the magnitude of the stimulus, but its characteristics can also be modulated by potentiators Our knowledge of the stimulus-secretion coupling has markedly progressed over the past few years, but elucidation of several important steps remains a challenging goal. There is no doubt that parallel measurements of insulin release, of ionic fluxes and of membrane potential in B-cells will still contribute to that understanding.