Model for synchronization of pancreatic beta-cells by gap junction coupling

Area of Science:

• Computational biology
• Electrophysiology
• Cellular physiology

Background:

• Pancreatic beta-cells exhibit regular electrical bursting in clusters, modeled by the Chay-Keizer model.
• Isolated cells typically show disorganized spiking, potentially due to stochastic channel fluctuations.
• Previous models assumed infinite gap junctional conductance, simplifying clusters to a single 'supercell'.

Purpose of the Study:

• To extend previous models by investigating multicell dynamics with finite gap junctional conductance.
• To study the synchronization process of pancreatic beta-cells within a cluster.
• To explore how gap junctional conductance influences electrical bursting and calcium oscillations.

Main Methods:

• Developed a multicell model with finite gap junctional conductance.
• Simulated electrical activity and synchronization in clusters of pancreatic beta-cells.
• Analyzed the relationship between gap junctional conductance, burst period, and calcium oscillation amplitude.

Main Results:

• Sufficiently large clusters synchronize and exhibit regular bursting with moderate gap junctional conductance.
• An optimal gap junctional conductance (150-250 pS) was identified, yielding longer burst periods and greater calcium amplitudes than infinite conductance.
• Model predictions align with experimental data on beta-cell gap junction conductance.

Conclusions:

• Finite gap junctional conductance is crucial for realistic modeling of pancreatic beta-cell cluster dynamics.
• Synchronization and bursting in beta-cell clusters are dependent on specific, physiologically relevant conductance values.
• The identified optimality suggests a regulatory mechanism for insulin secretion through coordinated electrical activity.