Membrane potential and intercellular calcium during glucose challenge in mouse islet of Langerhans.

The present work was undertaken to study the effects of the addition and removal of glucose on the calcium concentration of the intercellular space [Ca2+]o of islets of Langerhans. The removal of glucose hyperpolarize the beta-cell membrane to near- 60 mV and induced a biphasic response in [Ca2+]o. On the other hand, the addition of glucose (11 mM) depolarized beta-cell, inducing a biphasic electrical activity and concomitant changes in the [Ca2+]o. During the continuous membrane electrical activity, which characterized the first phase of glucose evoked biphasic response, the [Ca2+]o decreased. In the second phase, the [Ca2+]o displayed an oscillatory behavior concomitantly with the membrane potential.