INVESTIGADORES
PONCE DAWSON Silvina Martha
artículos
Título:
Saltatory propagation of Ca2+ waves by Ca2+ sparks
Autor/es:
JOEL E. KEIZER; GREGORY D. SMITH; SILVINA PONCE DAWSON; JOHN E. PEARSON
Revista:
BIOPHYSICAL JOURNAL
Referencias:
Año: 1998 vol. 75 p. 595 - 600
ISSN:
0006-3495
Resumen:
Punctate releases of Ca2+, called
Ca2+ sparks, originate at the regular array of t-tubules in
cardiac myocytes and skeletal muscle. During Ca2+ overload
sparks serve as sites for the initiation and propagation of
Ca2+ waves in myocytes. Computer simulations of
spark-mediated waves are performed with model release sites that
reproduce the adaptive Ca2+ release observed for the
ryanodine receptor. The speed of these waves is proportional to the
diffusion constant of Ca2+, D, rather than
, as is true for reaction-diffusion equations in
a continuous excitable medium. A simplified "fire-diffuse-fire" model that mimics the properties of Ca2+-induced
Ca2+ release (CICR) from isolated sites is used to explain
this saltatory mode of wave propagation. Saltatory and continuous wave
propagation can be differentiated by the temperature and
Ca2+ buffer dependence of wave speed.