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Could someone put in the values for the permeabilities in a typical cell? like calculate how the Nernst equals -70mV at rest? 129.31.72.52 21:37, 19 June 2007 (UTC)
For such a long text on such a science-heavy subject, it has very few citations? I feel there are a lot of facts in there which it wouldn't hurt to give sources for. For instance, why is the resting potential pegged at -70 mV? Who measured that? -- Miturian ( talk) 09:48, 9 January 2014 (UTC)
Could someone please extend the first sentence to include something like "...is a term in [whatever] biology" so that people like me, using "random article" to check stuff, know in what context this term is used? Is tis molecular or cell biology? Tierlieb 19:48, 2 November 2007 (UTC)
im a first year undergrad, so far this term came up in a lecture for psychobilogy —Preceding unsigned comment added by 137.205.77.223 ( talk) 01:34, 15 May 2008 (UTC)
There are three articles now which discuss very much the same things with numerous repetitions and description of the same material in different terms.
As it was already suggested by Methoxyroxy 12:37, 2 November 2006 (UTC), it needs a really big clean-up and optimization. There is a lot of confusion there so I will do this albeit not at once. I will move different parts between these three articles, edit and unify their style etc. At later stage I will need someone who is native English speaker to do spellcheck. Rvfrolov ( talk) 20:52, 2 January 2009 (UTC)
The article will be messy for a while until i finish editing. It may take several days Rvfrolov ( talk) 22:41, 2 January 2009 (UTC)
You are right. Worse, there is no mention here of potassium leak channels, the ones that set the resting potentials. Uniporters are oddly credited? —Preceding unsigned comment added by Cagedcalcium ( talk • contribs) 01:11, 11 September 2009 (UTC)
Someone wrote "At physiological temperature, about 29.5 C" surely physiological temperature is 37°C? Citation anyone? 83.146.15.190 ( talk) 18:34, 27 April 2009 (UTC)
The article does not explain why the resting potential is negative despite both media having zero global charge. Which I believe is due to negative charged proteins inside (although I don't understand how does this not violate zero global charge). It also does not mention that the membrane potential is given by Vm = Vin - Vout. Rend ( talk) 20:06, 18 March 2010 (UTC)
This article is not very reader friendly. I made just one simple change, but it is only one of many needed. The article is much too wordy. I understand that the average person will not be able to understand the article. However, keep in mind that many beginning students will come to this page seeking help. It should be ESPECIALLY for them. That's the purpose of wiki; its not a platform to pontificate. I suggest going through this and making similar changes as I did, ionic species-simplified as ions. Seriously? —Preceding unsigned comment added by 72.213.53.41 ( talk) 07:14, 19 March 2011 (UTC)
I am going to remove the "lead too long" and "refimprove" tags added to this article today. The lead is not overly long given the length of the article, and the need for references doesn't require a tag to be noticed. There is no doubt that this is a pretty low-quality article which needs improvement in numerous ways, but defacing it with big ugly tags at the top doesn't promote that, in my opinion. Looie496 ( talk) 17:08, 19 March 2011 (UTC)
I think ion permeabilities in Millman equation should be replaced by conductances. Ref: Ove Sten-Knudsen, "Biological membranes: theory of transport, potentials and electric impulses", Cambridge University Press, 2002, p. 382 — Preceding unsigned comment added by Hamid.mirzaei ( talk • contribs) 18:25, 12 December 2011 (UTC)
An essential point is missing: Is Na+/K+-ATPase working until ATP is exhausted? Or until there is no Na+ or K+ to be pumped? Probably there is some sort of negative feedback. But how can cAMP measure the Membrane potential, because it is no Transmembrane protein ? The negative feedback should be slow enough (T > 10 ms) not to prevent the emergence of the Action potential. Who knows a correct answer? -- 92.193.88.132 ( talk) 17:36, 6 March 2012 (UTC)
Can this sentence be clarified, specifically:
the effect of charge on electrochemical potential significantly larger then the effect of charge on concentration - is this a general statement or true in all cases?
And if charge is more significant then concentration in influencing electrochemical potential why does a small change in concentration greatly effect electropotential? Or does it mean electrochemical potential? Either way how does it make any sense, is it correct or nonsense and what is the exact meaning behind the message?
I am a beginning student trying to wrap my head around the fundamentals of membrane potential physiology. A couple of other questions I have:
1) What is the reason Na+ stays at its location right across the barrier on the extracellular side of the membrane? Diffusion? Electrochemical potential? Electric Charge repulsion?
2) If the answer is the electrochemical gradient/potential, because it is trying to move to a "less" positive potential.. if its located extracellularlly isn't that the "great unknown" where any molecules/cells/protein etc. are able to float by and possibly influence it? What happens if one of these has a "LESS" positive potential then the membrane that Na+ is currently attracted?
3) Can someone explain why can't Na+ be used for the entire process to establish the same voltage interactions leading from resting to action potential (as long as thier was less concentration intracellularly... if it is about LESS positivity ..Or vice versa for K+?)? — Preceding unsigned comment added by Trancelot ( talk • contribs)
Some time ago I wrote an interactive tutorial on the origin of the resting membrane potential which is available on my university website: http://www.st-andrews.ac.uk/~wjh/neurotut/mempot.html I have received some positive (unsolicited) feedback from a number of neuroscience students and staff in various other institutions, and I think it answers some of the questions raised on this talk page. I'm therefore minded to put a link to it in the "External links" section of the article. But I wrote it, and I don't want to contravene vanity publishing guidelines, so I thought I'd put it here for a while and see if there were any strong opinions against doing this. Wjheitler ( talk) 20:05, 27 September 2013 (UTC)
The comment(s) below were originally left at Talk:Resting potential/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.
Rated "high" for consistency with action potential. Article needs references/sources. - tameeria 00:37, 19 February 2007 (UTC) |
Last edited at 00:37, 19 February 2007 (UTC). Substituted at 04:11, 30 April 2016 (UTC)
If simple diffusion is meant to be a passive mean where each ion is independent from each other ion IN each side AND in each compartment.
Then a electric gradient is meant to be an active mean where each ion becomes dependent to each ion OR electrode IN each side AND each compartment.
An electric gradient EXCLUDES all passive mean thus a simple diffusion can't exist when there is a potential difference. Somasimple ( talk) 08:38, 27 August 2018 (UTC)
So we admit the electroneutrality is slightly violated across the membrane. The external milieu contains a little amount/imbalance m of positive ions. Here is a picture of the problem
So we expect that for 2 cells the model works and we have now (see picture)
and if we have 100 cells we get (see picture)
THE VIOLATION GROWS AS THE CELL COUNT GROWS!!! But a cell contains only a m imbalance but sees n*m positive ions outside! This model seems not valid. Somasimple ( talk) 11:16, 29 August 2018 (UTC)
In my opinion and in accordance with the text the equation should contain RELATIVE permeabilities. At the moment all the permeability-quotients are one. — Preceding unsigned comment added by Koitus~nlwiki ( talk • contribs) 18:27, 19 October 2018 (UTC)
The article correctly states that when a membrane is permeable/conducting to 2 or more ions with different Nernst potentials a steady-state will be reached where the net flux/current is zero, and this steady state occurs at a membrane potential which is, qualitatively, a compromise between the relevant Nernst potentials. However, although 2 different equations are given to describe this compromise, the 2 equations are actually incompatible with each other. The first assumes the conductances are fixed and unrelated to the ion concentrations (which enter only via the Nernst potentials), while the second assumes the permeabilities are fixed, and that the ions move independently of each other. This confusion is common in most elementary accounts of resting potential. The correct view is that both equations are useful simplifications which make different assumptions about how ions actually move, and a better but far more complicated account could be given by specifying the detailed ways ions move through the various types of channels. based on their structures. I recommend the article be modified to say that there are 2 widely used but different ways to quantitatively describe resting membrane potential: one assumes the I-V relations are straight (which they rarely are when the Nernst potentials are nonzero) and the other that ions move independently. These assumptions lead to slightly different equations - one involving weighted sums of logarithms of concentration ratios, the other involving logarithms of weighted sums of concentration ratios. There is no good simple way to avoid this issue.
The other crucial issue is, which types of ion channel are actually involved in generating the resting potential? The article correctly says that the dominant channel is potassium (specifically, mostly 2p-domain K channels), but doesn't really clarify which other types of channel (primarily sodium) are also, to a lesser degree, involved. Recent evidence suggests that a unique channel type, NALCN, provides the long-sought sodium leak conductance (Lu, B., Zhang, Q., Wang, H., Wang, Y., Nakayama, M., and Ren, D. (2010); Ren,D. Neuron 72, December 22, 2011 ª2011. Extracellular calcium controls background current and neuronal excitability via an UNC79-UNC80-NALCN cation channel complex. Neuron 68, 488–499; Kschonsak, M., Chua, H.C., Noland, C.L. et al. Structure of the human sodium leak channel NALCN. Nature (2020). https://doi.org/10.1038/s41586-020-2570-8
It's rather unfortunate that the most basic feature of electrophysiology, the resting potential, is actually rather difficult to explain succinctly and correctly! This is not the fault of the primary author of this article, since most standard texts also flub the issue. Paulhummerman ( talk) 21:58, 13 October 2020 (UTC)
![]() | This article is rated Start-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||||||||||||||||||||||
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Could someone put in the values for the permeabilities in a typical cell? like calculate how the Nernst equals -70mV at rest? 129.31.72.52 21:37, 19 June 2007 (UTC)
For such a long text on such a science-heavy subject, it has very few citations? I feel there are a lot of facts in there which it wouldn't hurt to give sources for. For instance, why is the resting potential pegged at -70 mV? Who measured that? -- Miturian ( talk) 09:48, 9 January 2014 (UTC)
Could someone please extend the first sentence to include something like "...is a term in [whatever] biology" so that people like me, using "random article" to check stuff, know in what context this term is used? Is tis molecular or cell biology? Tierlieb 19:48, 2 November 2007 (UTC)
im a first year undergrad, so far this term came up in a lecture for psychobilogy —Preceding unsigned comment added by 137.205.77.223 ( talk) 01:34, 15 May 2008 (UTC)
There are three articles now which discuss very much the same things with numerous repetitions and description of the same material in different terms.
As it was already suggested by Methoxyroxy 12:37, 2 November 2006 (UTC), it needs a really big clean-up and optimization. There is a lot of confusion there so I will do this albeit not at once. I will move different parts between these three articles, edit and unify their style etc. At later stage I will need someone who is native English speaker to do spellcheck. Rvfrolov ( talk) 20:52, 2 January 2009 (UTC)
The article will be messy for a while until i finish editing. It may take several days Rvfrolov ( talk) 22:41, 2 January 2009 (UTC)
You are right. Worse, there is no mention here of potassium leak channels, the ones that set the resting potentials. Uniporters are oddly credited? —Preceding unsigned comment added by Cagedcalcium ( talk • contribs) 01:11, 11 September 2009 (UTC)
Someone wrote "At physiological temperature, about 29.5 C" surely physiological temperature is 37°C? Citation anyone? 83.146.15.190 ( talk) 18:34, 27 April 2009 (UTC)
The article does not explain why the resting potential is negative despite both media having zero global charge. Which I believe is due to negative charged proteins inside (although I don't understand how does this not violate zero global charge). It also does not mention that the membrane potential is given by Vm = Vin - Vout. Rend ( talk) 20:06, 18 March 2010 (UTC)
This article is not very reader friendly. I made just one simple change, but it is only one of many needed. The article is much too wordy. I understand that the average person will not be able to understand the article. However, keep in mind that many beginning students will come to this page seeking help. It should be ESPECIALLY for them. That's the purpose of wiki; its not a platform to pontificate. I suggest going through this and making similar changes as I did, ionic species-simplified as ions. Seriously? —Preceding unsigned comment added by 72.213.53.41 ( talk) 07:14, 19 March 2011 (UTC)
I am going to remove the "lead too long" and "refimprove" tags added to this article today. The lead is not overly long given the length of the article, and the need for references doesn't require a tag to be noticed. There is no doubt that this is a pretty low-quality article which needs improvement in numerous ways, but defacing it with big ugly tags at the top doesn't promote that, in my opinion. Looie496 ( talk) 17:08, 19 March 2011 (UTC)
I think ion permeabilities in Millman equation should be replaced by conductances. Ref: Ove Sten-Knudsen, "Biological membranes: theory of transport, potentials and electric impulses", Cambridge University Press, 2002, p. 382 — Preceding unsigned comment added by Hamid.mirzaei ( talk • contribs) 18:25, 12 December 2011 (UTC)
An essential point is missing: Is Na+/K+-ATPase working until ATP is exhausted? Or until there is no Na+ or K+ to be pumped? Probably there is some sort of negative feedback. But how can cAMP measure the Membrane potential, because it is no Transmembrane protein ? The negative feedback should be slow enough (T > 10 ms) not to prevent the emergence of the Action potential. Who knows a correct answer? -- 92.193.88.132 ( talk) 17:36, 6 March 2012 (UTC)
Can this sentence be clarified, specifically:
the effect of charge on electrochemical potential significantly larger then the effect of charge on concentration - is this a general statement or true in all cases?
And if charge is more significant then concentration in influencing electrochemical potential why does a small change in concentration greatly effect electropotential? Or does it mean electrochemical potential? Either way how does it make any sense, is it correct or nonsense and what is the exact meaning behind the message?
I am a beginning student trying to wrap my head around the fundamentals of membrane potential physiology. A couple of other questions I have:
1) What is the reason Na+ stays at its location right across the barrier on the extracellular side of the membrane? Diffusion? Electrochemical potential? Electric Charge repulsion?
2) If the answer is the electrochemical gradient/potential, because it is trying to move to a "less" positive potential.. if its located extracellularlly isn't that the "great unknown" where any molecules/cells/protein etc. are able to float by and possibly influence it? What happens if one of these has a "LESS" positive potential then the membrane that Na+ is currently attracted?
3) Can someone explain why can't Na+ be used for the entire process to establish the same voltage interactions leading from resting to action potential (as long as thier was less concentration intracellularly... if it is about LESS positivity ..Or vice versa for K+?)? — Preceding unsigned comment added by Trancelot ( talk • contribs)
Some time ago I wrote an interactive tutorial on the origin of the resting membrane potential which is available on my university website: http://www.st-andrews.ac.uk/~wjh/neurotut/mempot.html I have received some positive (unsolicited) feedback from a number of neuroscience students and staff in various other institutions, and I think it answers some of the questions raised on this talk page. I'm therefore minded to put a link to it in the "External links" section of the article. But I wrote it, and I don't want to contravene vanity publishing guidelines, so I thought I'd put it here for a while and see if there were any strong opinions against doing this. Wjheitler ( talk) 20:05, 27 September 2013 (UTC)
The comment(s) below were originally left at Talk:Resting potential/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.
Rated "high" for consistency with action potential. Article needs references/sources. - tameeria 00:37, 19 February 2007 (UTC) |
Last edited at 00:37, 19 February 2007 (UTC). Substituted at 04:11, 30 April 2016 (UTC)
If simple diffusion is meant to be a passive mean where each ion is independent from each other ion IN each side AND in each compartment.
Then a electric gradient is meant to be an active mean where each ion becomes dependent to each ion OR electrode IN each side AND each compartment.
An electric gradient EXCLUDES all passive mean thus a simple diffusion can't exist when there is a potential difference. Somasimple ( talk) 08:38, 27 August 2018 (UTC)
So we admit the electroneutrality is slightly violated across the membrane. The external milieu contains a little amount/imbalance m of positive ions. Here is a picture of the problem
So we expect that for 2 cells the model works and we have now (see picture)
and if we have 100 cells we get (see picture)
THE VIOLATION GROWS AS THE CELL COUNT GROWS!!! But a cell contains only a m imbalance but sees n*m positive ions outside! This model seems not valid. Somasimple ( talk) 11:16, 29 August 2018 (UTC)
In my opinion and in accordance with the text the equation should contain RELATIVE permeabilities. At the moment all the permeability-quotients are one. — Preceding unsigned comment added by Koitus~nlwiki ( talk • contribs) 18:27, 19 October 2018 (UTC)
The article correctly states that when a membrane is permeable/conducting to 2 or more ions with different Nernst potentials a steady-state will be reached where the net flux/current is zero, and this steady state occurs at a membrane potential which is, qualitatively, a compromise between the relevant Nernst potentials. However, although 2 different equations are given to describe this compromise, the 2 equations are actually incompatible with each other. The first assumes the conductances are fixed and unrelated to the ion concentrations (which enter only via the Nernst potentials), while the second assumes the permeabilities are fixed, and that the ions move independently of each other. This confusion is common in most elementary accounts of resting potential. The correct view is that both equations are useful simplifications which make different assumptions about how ions actually move, and a better but far more complicated account could be given by specifying the detailed ways ions move through the various types of channels. based on their structures. I recommend the article be modified to say that there are 2 widely used but different ways to quantitatively describe resting membrane potential: one assumes the I-V relations are straight (which they rarely are when the Nernst potentials are nonzero) and the other that ions move independently. These assumptions lead to slightly different equations - one involving weighted sums of logarithms of concentration ratios, the other involving logarithms of weighted sums of concentration ratios. There is no good simple way to avoid this issue.
The other crucial issue is, which types of ion channel are actually involved in generating the resting potential? The article correctly says that the dominant channel is potassium (specifically, mostly 2p-domain K channels), but doesn't really clarify which other types of channel (primarily sodium) are also, to a lesser degree, involved. Recent evidence suggests that a unique channel type, NALCN, provides the long-sought sodium leak conductance (Lu, B., Zhang, Q., Wang, H., Wang, Y., Nakayama, M., and Ren, D. (2010); Ren,D. Neuron 72, December 22, 2011 ª2011. Extracellular calcium controls background current and neuronal excitability via an UNC79-UNC80-NALCN cation channel complex. Neuron 68, 488–499; Kschonsak, M., Chua, H.C., Noland, C.L. et al. Structure of the human sodium leak channel NALCN. Nature (2020). https://doi.org/10.1038/s41586-020-2570-8
It's rather unfortunate that the most basic feature of electrophysiology, the resting potential, is actually rather difficult to explain succinctly and correctly! This is not the fault of the primary author of this article, since most standard texts also flub the issue. Paulhummerman ( talk) 21:58, 13 October 2020 (UTC)