Korean J Physiol Pharmacol.  2004 Feb;8(1):33-41.

Role of Stretch-Activated Channels in Stretch-Induced Changes of Electrical Activity in Rat Atrial Myocytes

• Youm JB
• Jo SH
• Leem CH
• Ho WK
• Earm YE

Abstract

We developed a cardiac cell model to explain the phenomenon of mechano-electric feedback (MEF), based on the experimental data with rat atrial myocytes. It incorporated the activity of ion channels, pumps, exchangers, and changes of intracellular ion concentration. Changes in membrane excitability and Ca2+ transients could then be calculated. In the model, the major ion channels responsible for the stretch-induced changes in electrical activity were the stretch-activated channels (SACs). The relationship between the extent of stretch and activation of SACs was formulated based on the experimental findings. Then, the effects of mechanical stretch on the electrical activity were reproduced. The shape of the action potential (AP) was significantly changed by stretch in the model simulation. The duration was decreased at initial fast phase of repolarization (AP duration at 20% repolarization level from 3.7 to 2.5 ms) and increased at late slow phase of repolarization (AP duration at 90% repolarization level from 62 to 178 ms). The resting potential was depolarized from -75 to -61 mV. This mathematical model of SACs may quantitatively predict changes in cardiomyocytes by mechanical stretch.

Keyword

Stretch-activated channels; Mechanical stretch; Atrial myocyte

MeSH Terms

Action Potentials
Animals
Ion Channels
Membrane Potentials
Membranes
Models, Theoretical
Muscle Cells*
Myocytes, Cardiac
Rats*
Ion Channels