These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Anoxia-induced increases in intracellular calcium concentration in primary cultures of rabbit thick ascending limb of Henle's loop.
    Author: Rose UM, Hartog A, Jansen JW, Van Os CH, Bindels RJ.
    Journal: Biochim Biophys Acta; 1994 Jul 18; 1226(3):291-9. PubMed ID: 8054361.
    Abstract:
    The effect of anoxia on intracellular Ca2+ concentration ([Ca2+]i) in primary cultures of medullary (mTAL) and cortical (cTAL) thick ascending limb of Henle's loop was investigated. Previously, we reported a method to monitor [Ca2+]i continuously in cultured proximal tubule cells during 1 h of anoxic incubation in the absence of glycolytic substrates [1]. Complete absence of O2 was realised by inclusion of a mixture of oxygenases in an anoxic chamber. As a result of substrate-free anoxia, [Ca2+]i started to rise in individual cells of mTAL and cTAL monolayers and reached maximal levels within 60 min after starting the anoxic incubation. Anoxia induced significant increases in [Ca2+]i from 76 +/- 1 (n = 176) to 469 +/- 18 nM (n = 203) in mTAL monolayers and from 58 +/- 1 (n = 91) to 442 +/- 27 nM (n = 106) in cTAL monolayers (P < 0.05). At the re-introduction of oxygen and glucose, elevated [Ca2+]i rapidly declined to 110 +/- 4 (n = 167) and 105 +/- 5 nM (n = 87) in mTAL and cTAL, respectively (P < 0.05). Removal of extracellular Ca2+ and addition of 0.1 mM La3+ partially prevented anoxia-induced increases in [Ca2+]i in both cell types. The L-type Ca2+ channel blocker D600 (1 microM) was as effective as Ca2+ removal and La3+ addition. Comparing mTAL and cTAL cells, only one difference was consistently observed. Prevention of Ca2+ influx by exposure to La3+ combined with Ca2+ removal or addition of 1 microM D600 had a greater inhibitory effect on anoxic [Ca2+]i values in mTAL than in cTAL monolayers, indicative of a larger role of Ca2+ influx through L-type Ca2+ channels in anoxia-induced increases in [Ca2+]i in the former cell type. In conclusion, substrate-free anoxia reversibly increases [Ca2+]i in primary cultures of cTAL and mTAL, which results from Ca2+ release from stores as well as from Ca2+ influx via D600-sensitive Ca2+ channels.
    [Abstract] [Full Text] [Related] [New Search]