Can EGTA increase intracellular calcium concentration?

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RedBull
RedBull's picture
Can EGTA increase intracellular calcium concentration?

Be more precise,

Can the application of calcium chelator EGTA in the patch pipette increase the intracellular calcium concentration?

RedBull
RedBull's picture
Oops......

Oops......

I think I had asked a very silly question.

I think many guys know that the intracellular calcium ion concentration will be buffered to very low levels with EGTA.
Therefore, it's quite non-sense that the application of EGTA will increase the calcium ion concentration.

I asked this question because I was reading the journals.

Perhaps, that's a problem with my comprehension abilities that I was confused about if EGTA can increase the calcium ion concentration.

Now, I had read another journal which implied clearly that EGTA will lowered that intracellular calcium ion concentration.

Now, I don't think this question needs reply.

littlebush
littlebush's picture
Do not mind ,even God will

Do not mind ,even God will make mistakes.Making mistakes will do no harm but if you do not want to make your puzzle clear and always take things for granted,it definitely will do harm to you in certain form.So I appreciate your aspiration to make things clear and this is the right direction for doing everything especially science.Good luck.

hyunjoe
hyunjoe's picture
Quote:I think I had asked a

Quote:

I think I had asked a very silly question.

I think many guys know that the intracellular calcium ion concentration will be buffered to very low levels with EGTA.
Therefore, it's quite non-sense that the application of EGTA will increase the calcium ion concentration.

It was not a silly question, I wonder why nobody has answered... Briefly, you CAN'T increase ONLY by adding EGTA in your pipette. However, you CAN increase the intracellular calcium concentration with an intra-pipette medium with EGTA+Ca2+ (see WEBMAXC chelator).

For example, the resting concentration of Ca2+ in the cell is 100-200 nM. You can determine some medium that can increase (in whole cell configuration) the concentration up to 1-10 M (more is hard to clamp). So, technically you can increase by this mean the intracellular calcium concentration by a combinaison in a buffer of high Ca2+ and EGTA. Note that by this way, the intracellular calcium concentration is clamped to the value wanted.

see PubMed, many articles use buffers like this to determine the Ca2+ dependence of a mecanism. See also Sigma or else that sell some buffers prepared with the mix of Ca2+ and EGTA.

Wanderermann
Wanderermann's picture
...can you pleased put here

...can you pleased put here wich is the journal that talk about the implication of EGTA in lowered tha intracellular Ca++?

Thanks.

Fraser Moss
Fraser Moss's picture
Here's one quick example

Here's one quick example

Neuroscience Letters Volume 271, Issue 3, 27 August 1999, Pages 171-174

The effects of changing intracellular Ca2+ buffering on the excitability of cultured dorsal root ganglion neurones

Ayar A, Storer C, Tatham EL, Scott RH.

Department of Biomedical Sciences, Institute of Medical Sciences, University of Aberdeen, Scotland, UK.

The whole cell patch clamp technique was used to study the effects of changes in [Ca2+]i on the excitability of cultured dorsal root ganglion (DRG) neurones. Increases in [Ca2+]i caused membrane depolarization, altered the characteristics of evoked action potentials and activated potassium, chloride and non-selective cation conductances. Mobilization of Ca2+ from intracellular stores with caffeine (1 mM) or ryanodine (10 microM) or photorelease of Ca2+ from DM-nitrophen gave rise to depolarizations suggesting a dominant inward current under our recording conditions of low [Ca2+]i buffering capacity. The actions of [Ca2+]i could be partially reversed by intracellular flash photolysis of diazo-2 but not by diazo-3. The electrophysiological properties of some DRG neurones were not influenced by changes in [Ca2+]i and we suggest that this is because in this heterogeneous culture some neurones do not express Ca2+-activated ion channels.

doi:10.1016/S0304-3940(99)00538-8

PMID: 10507696

andy123
andy123's picture
No. It can't. Through the use

No. It can't. Through the use of EGTA calcium ions are usually at least a thousandfold less concentrated than magnesium. Hence increasion is not possible.