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Modeling of the gap junction of pancreatic β -cells and the robustness of insulin secretion

View Article: PubMed Central - PubMed

ABSTRACT

Pancreatic β-cells are interconnected by gap junctions, which allow small molecules to pass from cell to cell. In spite of the importance of the gap junctions in cellular communication, modeling studies have been limited by the complexity of the system. Here, we propose a mathematical gap junction model that properly takes into account biological functions, and apply this model to the study of the β-cell cluster. We consider both electrical and metabolic features of the system. Then, we find that when a fraction of the ATP-sensitive K+ channels are damaged, robust insulin secretion can only be achieved by gap junctions. Our finding is consistent with recent experiments conducted by Rocheleau et al. Our study also suggests that the free passage of potassium ions through gap junctions plays an important role in achieving metabolic synchronization between β-cells.

No MeSH data available.


Two β-cells with different ḡCa values, where ḡCa =1100 pS (Cell 2), 900 pS (Cell 1), and Ge = 7 mM.
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f10-6_37: Two β-cells with different ḡCa values, where ḡCa =1100 pS (Cell 2), 900 pS (Cell 1), and Ge = 7 mM.

Mentions: To clarify the limitation of the linear coupling scheme, we have conducted the following numerical experiments. The results are shown in Figs. 11 and 12, in which the number of channels is Nc = 10 as in previous investigations. By comparing Figs. 11(a) and 4(a), Figs. 11(b) and 10, and Figs. 12 and 7, it becomes clear that the linear coupling scheme works very well except when the ḡK(ATP) values of individual β-cells are different as shown in Fig. 12(b). The variation of ḡCa values does not provide any problem as an approximation. This difference originates in how the intra-cellular potassium concentration is a ected by the parameter value variation. As shown in Fig. 15, only ḡK(ATP) variation has a ected the intracellular potassium concentration significantly. As a consequence, the precondition of for this scheme is lost.


Modeling of the gap junction of pancreatic β -cells and the robustness of insulin secretion
Two β-cells with different ḡCa values, where ḡCa =1100 pS (Cell 2), 900 pS (Cell 1), and Ge = 7 mM.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC5036665&req=5

f10-6_37: Two β-cells with different ḡCa values, where ḡCa =1100 pS (Cell 2), 900 pS (Cell 1), and Ge = 7 mM.
Mentions: To clarify the limitation of the linear coupling scheme, we have conducted the following numerical experiments. The results are shown in Figs. 11 and 12, in which the number of channels is Nc = 10 as in previous investigations. By comparing Figs. 11(a) and 4(a), Figs. 11(b) and 10, and Figs. 12 and 7, it becomes clear that the linear coupling scheme works very well except when the ḡK(ATP) values of individual β-cells are different as shown in Fig. 12(b). The variation of ḡCa values does not provide any problem as an approximation. This difference originates in how the intra-cellular potassium concentration is a ected by the parameter value variation. As shown in Fig. 15, only ḡK(ATP) variation has a ected the intracellular potassium concentration significantly. As a consequence, the precondition of for this scheme is lost.

View Article: PubMed Central - PubMed

ABSTRACT

Pancreatic β-cells are interconnected by gap junctions, which allow small molecules to pass from cell to cell. In spite of the importance of the gap junctions in cellular communication, modeling studies have been limited by the complexity of the system. Here, we propose a mathematical gap junction model that properly takes into account biological functions, and apply this model to the study of the β-cell cluster. We consider both electrical and metabolic features of the system. Then, we find that when a fraction of the ATP-sensitive K+ channels are damaged, robust insulin secretion can only be achieved by gap junctions. Our finding is consistent with recent experiments conducted by Rocheleau et al. Our study also suggests that the free passage of potassium ions through gap junctions plays an important role in achieving metabolic synchronization between β-cells.

No MeSH data available.