2024-03-28T08:37:11Zhttps://uvadoc.uva.es/oai/requestoai:uvadoc.uva.es:10324/59512021-06-23T09:48:01Zcom_10324_1133com_10324_931com_10324_894col_10324_1209
Alonso Alonso, María Teresa
Barrero, María José
Michelena, Pedro
Carnicero Gila, Estela María
Cuchillo Ibáñez, Inmaculada
García, Antonio G.
García-Sancho Martín, Francisco Javier
Montero Zoccola, María Teresa
Álvarez Martín, Javier
2014-09-15T11:53:11Z
2014-09-15T11:53:11Z
1999
Journal of Cell Biology, Enero 1999, vol. 144, n. 2, p. 241-254
0021-9525
http://uvadoc.uva.es/handle/10324/5951
241
2
254
Journal of Cell Biology
144
The presence and physiological role of Ca 2+
induced Ca 2+
release (CICR) in nonmuscle excitable
cells has been investigated only indirectly through measurements
of cytosolic [Ca 2+] ([Ca 2+]c
). Using targeted
aequorin, we have directly monitored [Ca 2+] changes
inside the ER ([Ca 2+]
ER
) in bovine adrenal chromaffin
cells. Ca 2+
entry induced by cell depolarization triggered
a transient Ca 2+release from the ER that was
highly dependent on [Ca 2+]
ER
and sensitized by low
concentrations of caffeine. Caffeine-induced Ca 2+
release
was quantal in nature due to modulation by
[Ca 2+]
ER
. Whereas caffeine released essentially all the
Ca 2+
from the ER, inositol 1,4,5-trisphosphate (InsP3)-
producing agonists released only 60Ð80%. Both InsP3
and caffeine emptied completely the ER in digitoninpermeabilized
cells whereas cyclic ADP-ribose had no
effect. Ryanodine induced permanent emptying of the
Ca 2+
stores in a use-dependent manner after activation
by caffeine. Fast confocal [Ca 2+]c
measurements
showed that the wave of [C 2+]c
induced by 100-ms depolarizing
pulses in voltage-clamped cells was delayed
and reduced in intensity in ryanodine-treated cells. Our
results indicate that the ER of chromaffin cells behaves
mostly as a single homogeneous thapsigargin-sensitive
Ca 2+
pool that can release Ca 2+
both via InsP3
receptors
or CICR.
eng
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/4.0/
Attribution-NonCommercial-NoDerivatives 4.0 International
Calcio - Metabolismo
Ca 2+ induced Ca 2+ Release in Chromaffin Cells Seen from inside the ER with Targeted Aequorin
info:eu-repo/semantics/article