help button home button Biophys. J.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Biophys. J. BioFAST: First Published March 18, 2005. doi:10.1529/biophysj.104.057745
© 2005 by the Biophysical Society.

A more recent version of this article appeared on June 1, 2005.
This Article
Right arrow Full Text (Rapid PDF)
Right arrow Supplemental File
Right arrow All Versions of this Article:
biophysj.104.057745v1
88/6/4421    most recent
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Faas, G. C
Right arrow Articles by Mody, I.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Faas, G. C
Right arrow Articles by Mody, I.

ELECTROPHYSIOLOGY

Kinetic Properties of DM-Nitrophen Binding to Calcium and Magnesium

Guido C Faas 1, Kinga Karacs 1, Julio L. Vergara 2 and Istvan Mody 3*

1 UCLA, Neurology
2 UCLA, Physiology
3 UCLA, Physiology & Neurology

* To whom correspondence should be addressed. E-mail: mody{at}ucla.edu.

Submitted on December 9, 2004
Revised on February 21, 2005
Accepted on 10 March 2005


  Abstract
Caged-Ca2+ compounds such as nitrophenyl-EGTA (NP-EGTA) and DM-nitrophen (DMn) are extremely useful in biological research, but their use in live cells is hampered by cytoplasmic [Mg2+]. We determined the properties of Ca2+ release from NP-EGTA and DMn by using Oregon Green BAPTA-5N to measure changes in [Ca2+] after UV flash photolysis in vitro, with or without Mg2+ present. A large fraction (65%) of NP-EGTA, which has a negligible Mg2+ affinity, uncages with a time constant of 10.3 ms resulting in relatively slow increases in [Ca2+]. Uncaging of DMn is considerably faster but DMn has a significant affinity for Mg2+ to complicate the uncaging process. With experimentally determined values for the Ca2+ and Mg2+ binding/unbinding rates of DMn and NP-EGTA, we built a mathematical model to assess the utility of NP-EGTA and DMn in rapid Ca2+-uncaging experiments in the presence of Mg2+. We discuss the advantages and disadvantages of using each compound under different conditions. To determine the kinetics of Ca2+ binding to biologically relevant Ca2+ buffers such as Ca2+-binding proteins (CBPs), the use of DMn is preferable even in the presence of Mg2+.

Key Words: NP-EGTA, caged calcium, modeling, photolysis




This article has been cited by other articles:


Home page
 J. Neurosci.Home page
A. D. Powell, E. C. Toescu, J. Collinge, and J. G. R. Jefferys
Alterations in Ca2+-Buffering in Prion-Null Mice: Association with Reduced Afterhyperpolarizations in CA1 Hippocampal Neurons
J. Neurosci., April 9, 2008; 28(15): 3877 - 3886.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
R. L. P. Habets and J. G. G. Borst
An Increase in Calcium Influx Contributes to Post-Tetanic Potentiation at the Rat Calyx of Held Synapse
J Neurophysiol, December 1, 2006; 96(6): 2868 - 2876.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Copyright © 2005 by the Biophysical Society.