Minimal Model for Intracellular Calcium Oscillations and Electrical Bursting in Melanotrope Cells of Xenopus Laevis

• Published in: Neural computation 2001-01, Vol.13 (1), p.113-137
• Main Authors: Cornelisse, L. Niels, Scheenen, Wim J. J. M., Koopman, Werner J. H., Roubos, Eric W., Gielen, Stan C. A. M.
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Calcium - metabolism; Electrophysiology; Fundamental and applied biological sciences. Psychology; General aspects. Models. Methods; Intracellular Membranes - metabolism; Melanocyte-Stimulating Hormones - metabolism; melanotropes; Membrane Potentials - physiology; Models, Neurological; Oscillometry; Osmolar Concentration; Pituitary Gland - cytology; Pituitary Gland - physiology; Sodium Channels - physiology; Vertebrates: nervous system and sense organs; Xenopus laevis; Xenopus laevis - physiology
• ISSN: 0899-7667; 1530-888X
• DOI: 10.1162/089976601300014655

A minimal model is presented to explain changes in frequency, shape, and amplitude of Ca oscillations in the neuroendocrine melanotrope cell of . It describes the cell as a plasma membrane oscillator with influx of extracellular Ca via voltage-gated Ca channels in the plasma membrane. The Ca oscillations in the melanotrope show specific features that cannot be explained by previous models for electrically bursting cells using one set of parameters. The model assumes a K -channel with slow Ca -dependent gating kinetics that initiates and terminates the bursts. The slow kinetics of this channel cause an activation of the K -channel with a phase shift relative to the intracellular Ca concentration. The phase shift, together with the presence of a Na channel that has a lower threshold than the Ca channel, generate the characteristic features of the Ca oscillations in the melanotrope cell.