PMID- 9681188
OWN - NLM
STAT- MEDLINE
DCOM- 19980824
LR  - 20191210
IS  - 0143-4160 (Print)
IS  - 0143-4160 (Linking)
VI  - 23
IP  - 4
DP  - 1998 Apr
TI  - A fluorometric method for estimating the calcium content of internal stores.
PG  - 251-9
AB  - The concentration of Ca2+ in intracellular stores is an important factor in many 
      aspects of Ca2+ signaling, including the generation of Ca2+ spikes, oscillations 
      and waves, control of mitochondrial respiration, and activation of store-operated 
      Ca2+ channels. Here we describe a consistent method for estimating the content of 
      stores, based on the release of stored Ca2+ by thapsigargin (TG) or ionomycin 
      (IO). Once released from stores, Ca2+ elevates [Ca2+]i transiently before it is 
      pumped across the plasma membrane. If the dependence of the pump rate on [Ca2+]i 
      is known, then the kinetics and amplitude of the Ca2+ transient allows the total 
      amount of releasable Ca2+ to be estimated. We develop this quantitative approach 
      and validate its use in human T cells, in which the Ca2+ clearance rate is an 
      approximately linear function of [Ca2+]i. Our results support the assumption that 
      the ER Ca2+ leak in resting T cells is unregulated, i.e. its rate is proportional 
      to luminal [Ca2+]. The characteristic time constant for basal Ca2+ release is 
      110-140 s, comparable to that for activation of Ca2+ release-activated Ca2+ 
      (CRAC) channels by TG and consistent with the dependence of ICRAC on store 
      depletion. This method for estimating store content may be useful for quantifying 
      the overlap between functionally distinct stores and for defining the relation 
      between store content and cellular responses.
FAU - Bergling, S
AU  - Bergling S
AD  - Institute of Theoretical Dynamics, University of California, Davis, USA.
FAU - Dolmetsch, R
AU  - Dolmetsch R
FAU - Lewis, R S
AU  - Lewis RS
FAU - Keizer, J
AU  - Keizer J
LA  - eng
GR  - R01 GM 45374/GM/NIGMS NIH HHS/United States
GR  - R01 RR 10081/RR/NCRR NIH HHS/United States
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - Netherlands
TA  - Cell Calcium
JT  - Cell calcium
JID - 8006226
RN  - 0 (Calcium Channels)
RN  - 0 (Enzyme Inhibitors)
RN  - 0 (Ionophores)
RN  - 56092-81-0 (Ionomycin)
RN  - 67526-95-8 (Thapsigargin)
RN  - EC 7.2.2.10 (Calcium-Transporting ATPases)
RN  - SY7Q814VUP (Calcium)
SB  - IM
MH  - Calcium/*analysis/metabolism
MH  - Calcium Channels/drug effects/metabolism
MH  - Calcium-Transporting ATPases/antagonists & inhibitors
MH  - Cell Compartmentation
MH  - Cytosol/metabolism
MH  - Endoplasmic Reticulum/enzymology
MH  - Enzyme Inhibitors/pharmacology
MH  - Fluorometry/*methods
MH  - Humans
MH  - Ion Transport
MH  - Ionomycin/pharmacology
MH  - Ionophores/pharmacology
MH  - T-Lymphocytes/*drug effects/metabolism
MH  - Thapsigargin/pharmacology
EDAT- 1998/07/29 00:00
MHDA- 1998/07/29 00:01
CRDT- 1998/07/29 00:00
PHST- 1998/07/29 00:00 [pubmed]
PHST- 1998/07/29 00:01 [medline]
PHST- 1998/07/29 00:00 [entrez]
AID - S0143-4160(98)90123-3 [pii]
AID - 10.1016/s0143-4160(98)90123-3 [doi]
PST - ppublish
SO  - Cell Calcium. 1998 Apr;23(4):251-9. doi: 10.1016/s0143-4160(98)90123-3.