RT info:eu-repo/semantics/article
T1 Calcium dynamics in bovine adrenal medulla chromaffin cell secretory granules
A1 Santo Domingo, Jaime
A1 Vay, Laura
A1 Camacho, Marcial
A1 Hernández San Miguel, Esther
A1 Fonteriz García, Rosalba Inés
A1 Domínguez Lobatón, María Carmen
A1 Montero Zoccola, María Teresa
A1 Moreno Díaz-Calderón, Alfredo
A1 Álvarez Martín, Javier
K1 Médula espinal - Calcio
AB The secretory granules constitute one of the less well-known compartments in terms of Ca2+ dynamics. They contain large amountsof total Ca2+, but the free intragranular [Ca2+] ([Ca2+]SG), the mechanisms for Ca2+ uptake and release from the granules and theirphysiological significance regarding exocytosis are still matters of debate. We used in the present work an aequorin chimera targetedto the granules to investigate [Ca2+]SG homeostasis in bovine adrenal chromaffin cells. We found that most of the intracellularaequorin chimera is present in a compartment with 50–100 lm Ca2+. Ca2+ accumulation into this compartment takes place mainlythrough an ATP-dependent mechanism, namely, a thapsigargin-sensitive Ca2+-ATPase. In addition, fast Ca2+ release was observedin permeabilized cells after addition of inositol 1,4,5-trisphosphate (InsP3) or caffeine, suggesting the presence of InsP3 andryanodine receptors in the vesicular membrane. Stimulation of intact cells with the InsP3-producing agonist histamine or with caffeinealso induced Ca2+ release from the vesicles, whereas acetylcholine or high-[K+] depolarization induced biphasic changes in vesicular[Ca2+], suggesting heterogeneous responses of different vesicle populations, some of them releasing and some taking up Ca2+during stimulation. In conclusion, our data show that chromaffin cell secretory granules have the machinery required for rapid uptakeand release of Ca2+, and this strongly supports the hypothesis that granular Ca2+ may contribute to its own secretion.
PB Federation of European Neuroscience Societies and Blackwell Publishing Ltd
SN 0953-816X
YR 2008
FD 2008
LK http://uvadoc.uva.es/handle/10324/5977
UL http://uvadoc.uva.es/handle/10324/5977
LA eng
NO European Journal of Neuroscience, 2008, vol. 28, p. 1265-1274
NO Producción Científica
DS UVaDOC
RD 24-nov-2024