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Insulin secretion in normal B-cells is pulsatile, a consequence of oscillations in the cell membrane potential (MP) and cytosolic calcium activity ([Ca(2+)](c)). We simultaneously monitored glucose-induced changes in [Ca(2+)](c) and in the mitochondrial membrane potential DeltaPsi, as a measure for ATP generation. Increasing the glucose concentration from(More)
Stimulus-Secretion Coupling (SSC) of pancreatic islet cells comprises electrical activity. Changes of the membrane potential (V(m)) are regulated by metabolism-dependent alterations in ion channel activity. This coupling is best explored in beta-cells. The effect of glucose is directly linked to mitochondrial metabolism as the ATP/ADP ratio determines the(More)
Skeletal muscle cells have been established as significant producers of IL-6 during exercise. This IL-6 production is discussed as one possible mediator of the beneficial effects of physical activity on glucose and fatty acid metabolism. IL-6 itself could be the exercise-related factor that upregulates and maintains its own production. We investigated this(More)
Type 2 diabetes mellitus is associated with alterations in bile acid (BA) signaling. The aim of our study was to test whether pancreatic β-cells contribute to BA-dependent regulation of glucose homeostasis. Experiments were performed with islets from wild-type, farnesoid X receptor (FXR) knockout (KO), and β-cell ATP-dependent K(+) (K(ATP)) channel gene(More)
OBJECTIVE—Ca 2ϩ-regulated K ϩ channels are involved in numerous Ca 2ϩ-dependent signaling pathways. In this study, we investigated whether the Ca 2ϩ-activated K ϩ channel of intermediate conductance SK4 (KCa3.1, IK1) plays a physiological role in pancreatic ␤-cell function. RESEARCH DESIGN AND METHODS—Glucose tolerance and insulin sensitivity were(More)
Free fatty acids (FFA) have been proposed to participate in the regulation of insulin release from pancreatic beta-cells (beta-cells). As a rise in cytosolic free Ca2+ ([Ca(2+)]i) is a key event for the stimulation of insulin secretion, the effects of saturated FFA on [Ca2+]i were investigated. Palmitate was used as a reference compound and [Ca2+]i was(More)
Pancreatic beta-cells respond to an unchanging stimulatory glucose concentration with oscillations in membrane potential (Vm), cytosolic Ca2+ concentration ([Ca2+]c), and insulin secretion. The underlying mechanisms are largely ascertained. Some particular details, however, are still in debate. Stimulus-secretion coupling (SSC) of beta-cells comprises(More)
Extracellular recording of the glucose-induced electrical activity of mouse islets of Langerhans on microelectrode arrays (MEAs) is an innovative and powerful tool to address beta-cell (patho-)physiology. In a dual approach we tested whether this technique can detect concentration-dependent drug effects as well as characterize alterations in beta-cell(More)
Within the last years, progress has been made in the knowledge of the properties of medically used nanoparticles and their toxic effects, but still, little is known about their influence on cellular processes of immune cells. The aim of our comparative study was to present the influence of two different nanoparticle types on subcellular processes of primary(More)