Depolarisation-evoked Ca2+ waves in the non-excitable rat megakaryocyte.
J Physiol
; 537(Pt 2): 371-8, 2001 Dec 01.
Article
en En
| MEDLINE
| ID: mdl-11731571
ABSTRACT
1. A combination of patch clamp, confocal microscopy and immunohistochemistry was used to examine the spatial properties of Ca2+ signalling in the rat megakaryocyte, a non-excitable cell type in which membrane potential can markedly modulate agonist-evoked Ca2+ release. 2. Intracellular calcium ion concentration ([Ca2+]i) increases, stimulated by both ADP and depolarisation, frequently originated from a peripheral locus and spread as a wave throughout the cell. Spatially restricted [Ca2+]i increases, consistent with elementary Ca2+ release events, were occasionally observed prior to ADP-evoked waves. 3. ADP- and depolarisation-evoked Ca2+ waves travelled approximately twice as fast around the periphery of the cell compared to across its radius, leading to a curvilinear wavefront. There was no significant difference between wave velocities generated by the two stimuli. 4. Immunohistochemical staining of type III IP3 receptors, the endoplasmic reticulum-specific protein GRP78/BiP and calreticulin indicated a major peripheral location of the cellular Ca2+ stores which probably accounts for the accelerated wave velocity at the cell periphery. 5. These data demonstrate that [Ca2+]i increases, stimulated by depolarisation or the agonist ADP, have indistinguishable spatial properties, providing evidence that similar underlying mechanisms are responsible for their generation.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Megacariocitos
/
Calcio
Límite:
Animals
Idioma:
En
Revista:
J Physiol
Año:
2001
Tipo del documento:
Article
País de afiliación:
Reino Unido