Mathematical modeling demonstrates how multiple slow processes can provide adjustable control of islet bursting

Abstract

Pancreatic islets exhibit bursting oscillations that give rise to oscillatory Ca²⁺ entry and insulin secretion from β-cells. These oscillations are driven by a slowly activating K⁺ current, K_slow, which is composed of two components: an ATP-sensitive K⁺ current and a Ca²⁺-activated K⁺ current through SK4 channels. Using a mathematical model of pancreatic β-cells, we analyze how the factors that comprise K_slow can contribute to bursting. We employ the dominance factor technique developed recently to do this and demonstrate that the contributions that the slow processes make to bursting are non-obvious and often counter-intuitive, and that their contributions vary with parameter values and are thus adjustable.

Keywords::

• calcium
• electrical activity
• oscillations
• currents
• β-cell