Mechanically induced potentials in fibroblasts from human right atrium

Citation
A. Kamkin et al., Mechanically induced potentials in fibroblasts from human right atrium, EXP PHYSIOL, 84(2), 1999, pp. 347-356
Citations number
34
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physiology
Journal title
EXPERIMENTAL PHYSIOLOGY
ISSN journal
0958-0670 → ACNP
Volume
84
Issue
2
Year of publication
1999
Pages
347 - 356
Database
ISI
SICI code
0958-0670(199903)84:2<347:MIPIFF>2.0.ZU;2-C
Abstract
It has been shown that cardiac fibroblasts of the human heart are electrica lly non-excitable and mechanosensitive. The resting membrane potential of t hese cells is -15.9 +/- 2.1 mV and the membrane resistance is 4.1 +/- 0.1 G Omega. Rhythmic contractions of the myocardium associated with stretch of the surrounding tissue produce reversible changes in the membrane potential of cardiac fibroblasts, These mechanically induced potentials (MIPs) follo w the rhythm of myocardial contractions. Simultaneous recording of the acti on potential of cardiomyocytes and MIPs of cardiac fibroblasts demonstrates a delay of 40.0 +/- 0.4 ms after the action potential before the appearanc e of the MIP. Contraction produces a MIP which is more positive or more neg ative than the reversal potential - the membrane potential due to current i njection at which the MIP reverses its direction. Regardless of the initial orientation of the MIP, intracellular polarization increases the amplitude rewards the reversal potential if the background MIP had depolarized the m embrane or away from the reversal potential if the initial background MIP h ad hyperpolarized the membrane. Artificial intracellular polarization chang ed the amplitude but not the frequency of the MIP. The pool of electrically non-excitable mechanosensitive cells, which change their electrical activi ty during contraction and relaxation of the heart, may play a role in the m echano-electrical feedback mechanism which has to be taken into account in the normal function of the heart as well as in pathological processes.