Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
MODEL STUDIES OF THE ROLE OF MECANOSENSITIVE CURRENTS IN THE GENERATION OF CARDIAC-ARRHYTHMIAS
Autore:
RICE JJ; WINSLOW RL; DEKANSKI J; MCVEIGH E;
Indirizzi:
JOHNS HOPKINS UNIV,SCH MED,DEPT BIOMED ENGN,720 RUTLAND AVE BALTIMOREMD 21205 UNIV LEEDS,DEPT PHYSIOL LEEDS LS2 9NQ W YORKSHIRE ENGLAND
Titolo Testata:
Journal of theoretical biology
fascicolo: 4, volume: 190, anno: 1998,
pagine: 295 - 312
SICI:
0022-5193(1998)190:4<295:MSOTRO>2.0.ZU;2-B
Fonte:
ISI
Lingua:
ENG
Soggetto:
ACTIVATED ION CHANNELS; CONTRACTION-EXCITATION FEEDBACK; ACTION-POTENTIAL CHANGES; RABBIT SINOATRIAL NODE; CULTURED CHICK HEART; WORKING RAT-HEART; VENTRICULAR MYOCYTES; MECHANOELECTRICAL FEEDBACK; DEPENDENT CHANGES; XENOPUS OOCYTES;
Tipo documento:
Review
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
101
Recensione:
Indirizzi per estratti:
Citazione:
J.J. Rice et al., "MODEL STUDIES OF THE ROLE OF MECANOSENSITIVE CURRENTS IN THE GENERATION OF CARDIAC-ARRHYTHMIAS", Journal of theoretical biology, 190(4), 1998, pp. 295-312

Abstract

Mechano-electrical feedback is studied by incorporating linear, instantaneously activating mechano-sensitive conductances into single cardiac cell models, as well as one-and two-dimensional cardiac network models. The models qualitatively reproduce effects of maintained mechanical stretch on experimentally measured action potential characteristicssuch as amplitude, maximum diastolic potential, peak upstroke velocity, and conduction velocity. Models are also used to simulate stretch-induced depolarizations, action potentials, and arrhythmias produced bypulsatile volume changes in left ventricle of dog. The mechano-sensitive conductance threshold for a stretch-induced action potential is closely related to the magnitude of the time-independent K+ current, I-Kl, which offsets inward mechano-sensitive current. Activation of mechano-sensitive conductances in small, spatially localized region of cells can evoke graded depolarizations, propagating ectopic beats, and if timed appropriately, spiral reentrant waves. Mechano-sensitive conductance changes required to evoke these responses are well within the physiologically plausible range. Results therefore indicate that many mechano-electrical feedback effects can be modeled using linear, instantaneously activating mechano-sensitive conductances. As an example of how stretch can occur in real human hearts, magnetic resonance images with saturation tagging are used to reconstruct the three-dimensional left ventricular wall motion. In patients with infarcts or recent ischemic events, ''paradoxical deformation'' is observed in that regions of myocardium are stretched rather than contracted during systole. In contrast, normal hearts contract uniformly with no stretch during systole. Paradoxical deformations in ischemic hearts may therefore present one possible substrate for the mechanically induced arrhythmias modeled above. (C) 1998 Academic Press Limited.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/12/20 alle ore 13:45:34