2024-03-28T22:06:16Zhttps://uvadoc.uva.es/oai/requestoai:uvadoc.uva.es:10324/59802021-06-23T09:48:08Zcom_10324_1133com_10324_931com_10324_894col_10324_1209
Ca2+ Dynamics in the Secretory Vesicles of Neurosecretory PC12 and INS1 Cells
Santo Domingo, Jaime
Fonteriz García, Rosalba Inés
Domínguez Lobatón, María Carmen
Montero Zoccola, María Teresa
Moreno Díaz-Calderón, Alfredo
Álvarez Martín, Javier
Calcio - Metabolismo
We have investigated the dynamics of the free
[Ca2+] inside the secretory granules of neurosecretory PC12
and INS1 cells using a low-Ca2+-affinity aequorin chimera
fused to synaptobrevin-2. The steady-state secretory granule
[Ca2+] ([Ca2+]SG] was around 20–40 lM in both cell types,
about half the values previously found in chromaffin cells.
Inhibition of SERCA-type Ca2+ pumps with thapsigargin
largely blocked Ca2+ uptake by the granules in
Ca2+-depleted permeabilized cells, and the same effect was
obtained when the perfusion medium lacked ATP. Consistently,
the SERCA-type Ca2+ pump inhibitor benzohydroquinone
induced a rapid release of Ca2+ from the granules
both in intact and permeabilized cells, suggesting that the
continuous activity of SERCA-type Ca2+ pumps is essential
to maintain the steady-state [Ca2+]SG. Both inositol 1,4,
5-trisphosphate (InsP3) and caffeine produced a rapid Ca2+
release from the granules, suggesting the presence of InsP3
and ryanodine receptors in the granules. The response to
high-K+ depolarization was different in both cell types, a
decrease in [Ca2+]SG in PC12 cells and an increase in
[Ca2+]SG in INS1 cells. The difference may rely on the
heterogeneous response of different vesicle populations in
each cell type. Finally, increasing the glucose concentration
triggered a decrease in [Ca2+]SG in INS1 cells. In conclusion,
our data show that the secretory granules of PC12 and INS1
cells take up Ca2+ through SERCA-type Ca2+ pumps and
can release it through InsP3 and ryanodine receptors, supporting
the hypothesis that secretory granule Ca2+ may be
released during cell stimulation and contribute to secretion.
2014-09-16T10:11:25Z
2014-09-16T10:11:25Z
2014-09-16T10:11:25Z
2010
info:eu-repo/semantics/article
Cellular and Molecular Neurobiology, 2010, vol. 30, p. 1267-1274
0272-4340
http://uvadoc.uva.es/handle/10324/5980
10.1007/s10571-010-9572-2
1267
1274
Cellular and Molecular Neurobiology
30
eng
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/4.0/
Attribution-NonCommercial-NoDerivatives 4.0 International
Springer Verlag