| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Biophysical Journal 56: 229-242 (1989)
© 1989 the Biophysical Society
Department of Chemistry, University of California, Davis 95616.
ABSTRACT
Based on the existence of ATP-sensitive potassium channels in the plasma membrane of pancreatic beta cells, we develop a quantitative explanation of the electrical activity observed in pancreatic islets. The proposed mechanism involves the voltage-dependent inward calcium and outward potassium currents described by Rorsman and Trube (1986), which are voltage-activated when an increase in the cytoplasmic ATP/ADP ratio decreases the conductance of the ATP-sensitive potassium channels. It is proposed that modulation of the ATP/ADP ratio occurs through calcium inhibition of oxidative phosphorylation. In this picture the mitochondria serve as a transducer of metabolic activity whose sensitivity is modulated by cytosolic calcium. Solution of the differential equations that describe this mechanism gives rise to both bursting and continuous spiking electrical activity similar to that observed experimentally. While the mechanism for bursting in this model involves the ATP/ADP ratio, the feedback is still provided by calcium, as originally proposed by Chay and Keizer (1983) using a Ca2+-activated potassium conductance. A mixed-model, which includes both ATP-sensitive and Ca2+-activated potassium conductances, also reproduces the experimentally observed electrical activity and may correspond more closely to the actual situation in vivo.
This article has been cited by other articles:
 |
|
 |
|
  M. E. Meyer-Hermann The Electrophysiology of the {beta}-Cell Based on Single Transmembrane Protein Characteristics Biophys. J., October 15, 2007; 93(8): 2952 - 2968. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Bertram, L. S. Satin, M. G. Pedersen, D. S. Luciani, and A. Sherman Interaction of Glycolysis and Mitochondrial Respiration in Metabolic Oscillations of Pancreatic Islets Biophys. J., March 1, 2007; 92(5): 1544 - 1555. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. S. Nunemaker, R. Bertram, A. Sherman, K. Tsaneva-Atanasova, C. R. Daniel, and L. S. Satin Glucose Modulates [Ca2+]i Oscillations in Pancreatic Islets via Ionic and Glycolytic Mechanisms Biophys. J., September 15, 2006; 91(6): 2082 - 2096. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Jo, H. Kang, M. Y. Choi, and D.-S. Koh How Noise and Coupling Induce Bursting Action Potentials in Pancreatic {beta}-Cells Biophys. J., September 1, 2005; 89(3): 1534 - 1542. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. G. Pedersen, R. Bertram, and A. Sherman Intra- and Inter-Islet Synchronization of Metabolically Driven Insulin Secretion Biophys. J., July 1, 2005; 89(1): 107 - 119. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Bertram, L. Satin, M. Zhang, P. Smolen, and A. Sherman Calcium and Glycolysis Mediate Multiple Bursting Modes in Pancreatic Islets Biophys. J., November 1, 2004; 87(5): 3074 - 3087. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. L. Zimliki, D. Mears, and A. Sherman Three Roads to Islet Bursting: Emergent Oscillations in Coupled Phantom Bursters Biophys. J., July 1, 2004; 87(1): 193 - 206. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. Aguilar-Bryan and J. Bryan Molecular Biology of Adenosine Triphosphate-Sensitive Potassium Channels Endocr. Rev., April 1, 1999; 20(2): 101 - 135. [Abstract] [Full Text]
|
|
|
|
 |
|
 G. Magnus and J. Keizer Model of beta -cell mitochondrial calcium handling and electrical activity. I. Cytoplasmic variables Am J Physiol Cell Physiol, April 1, 1998; 274(4): C1158 - C1173. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Magnus and J. Keizer Model of beta -cell mitochondrial calcium handling and electrical activity. II. Mitochondrial variables Am J Physiol Cell Physiol, April 1, 1998; 274(4): C1174 - C1184. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
