Calcium current activated by depletion of calcium stores in Xenopus oocytes.
Calcium current activated by depletion of calcium stores in Xenopus oocytes.
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DOI：
10.1085/jgp.109.6.703
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发表时间：
1997-06
期刊：
影响因子：
--
通讯作者：
Tsien RY
中科院分区：
文献类型：
--
作者：
Yao Y;Tsien RY
Ca2+ currents activated by depletion of Ca2+ stores in Xenopus oocytes were studied with a two-electrode voltage clamp. Buffering of cytosolic Ca2+ with EGTA and MeBAPTA abolished ICl(Ca) and unmasked a current in oocytes that was activated by InsP3 or ionomycin in minutes and by thapsigargin or the chelators themselves over hours. At −60 mV in 10 mM extracellular CaCl2, the current was typically around −90 or −160 nA in oocytes loaded with EGTA or MeBAPTA, respectively. This current was judged to be a Ca2+-selective current for the following reasons: (a) it was inwardly rectifying and reversed at membrane potentials usually more positive than +40 mV; (b) it was dependent on extracellular [CaCl2] with K m = 11.5 mM; (c) it was highly selective for Ca2+ against monovalent cations Na+ and K+, because replacing Na+ and K+ by N-methyl-d-glucammonium did not reduce the amplitude or voltage dependence of the current significantly; and (d) Ca2+, Sr2+, and Ba2+ currents had similar instantaneous conductances, but Sr2+ and Ba2+ currents appeared to inactivate more strongly than Ca2+. This Ca2+ current was blocked by metal ions with the following potency sequence: Mg2+ << Ni2+ ≈ Co2+ ≈ Mn2+ < Cd2+ << Zn2+ << La3+. It was also inhibited by niflumic acid, which is commonly used to block ICl(Ca). PMA partially inhibited the Ca2+ current, and this effect was mostly abolished by calphostin C, indicating that the Ca2+ current is sensitive to protein kinase C. These results are the first detailed electrophysiological characterization of depletion-activated Ca2+ current in nondialyzed cells. Because exogenous molecules and channels are easy to introduce into oocytes and the distortions in measuring ICl(Ca) can now be bypassed, oocytes are now a superior system in which to analyze the activation mechanisms of capacitative Ca2+ influx.
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DOI：
10.1085/jgp.88.3.293
发表时间：
1986-09
期刊：
The Journal of general physiology
影响因子：
--
作者：
Hess P;Lansman JB;Tsien RW
通讯作者：
Tsien RW
DOI：
10.1098/rspb.1987.0033
发表时间：
1987-06-22
期刊：
PROCEEDINGS OF THE ROYAL SOCIETY SERIES B-BIOLOGICAL SCIENCES
影响因子：
--
作者：
PARKER, I;MILEDI, R
通讯作者：
MILEDI, R
影响因子：
64.8
作者：
HOTH, M;PENNER, R
通讯作者：
PENNER, R
影响因子：
3.5
作者：
CHARNET, P;BOURINET, E;NARGEOT, J
通讯作者：
NARGEOT, J
DOI：
10.1152/ajpcell.1995.268.6.c1485
发表时间：
1995-06-01
影响因子：
5.5
作者：
DELISLE, S;MAYR, GW;WELSH, MJ
通讯作者：
WELSH, MJ