Models of Excitation-Secretion Coupling in Pituitary Cells
Abstract
This report describes initial progress in developing a biophysical description of the electrical events surrounding hormone release in pituitary cells. Utilizing a model based on a membrane capacitance shunted by potassium and calcium channels, we are developing a computer program that will simulate the dynamic response of the transmembrane potential of GH3 cells in response to thyrotropia releasing hormone (TR4). When available, we are using published channel models of potassium and calcium channels. In parallel, we are pursuing a phase-plane description of the electrical properties. These models and analyses will be used to investigate the effect of temperature on membrane action potentials. In contrast to biophysical processes that operate at a single operating point and produce a continuous output of product, excitable cells in neural and cardiac systems appear to operate on a pulsed basis. For instance electrical activity in excitable cells is not represented by a slowly fluctuating membrane potential, but rather consists of bursts of action potentials. These potentials reflects the movement of charged ions across the cell membrane. Some ion movement appears primarily related to maintenance of the cell's membrane potential (Na+) while other ions (K+ and Ca++) act as second messengers by activating other biochemical processes.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 22, 1988
- Accession Number
- ADA204249
Entities
People
- C. F. Starmer
Organizations
- Duke University Hospital