Ion Channels of the Islets in Type 2 Diabetes.

Ca is an essential signal for pancreatic β-cell function. Ca plays critical roles in numerous β-cell pathways such as insulin secretion, transcription, metabolism, endoplasmic reticulum function, and the stress response. Therefore, β-cell Ca handling is tightly controlled. At the plasma membrane, Ca entry primarily occurs through voltage-dependent Ca channels. Voltage-dependent Ca channel activity is dependent on orchestrated fluctuations in the plasma membrane potential or voltage, which are mediated via the activity of many ion channels. During the pathogenesis of type 2 diabetes the β-cell is exposed to stressful conditions, which result in alterations of Ca handling. Some of the changes in β-cell Ca handling that occur under stress result from perturbations in ion channel activity, expression or localization. Defective Ca signaling in the diabetic β-cell alters function, limits insulin secretion and exacerbates hyperglycemia. In this review, we focus on the β-cell ion channels that control Ca handling and how they impact β-cell dysfunction in type 2 diabetes.