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Blocking agents for potassium channels also are: Cs+,H+,Ba++,Rb+,Sr++,Mg++,Na+,Capsaicin, Noxiustoxin, Chlotrimazol, Spermine, Spermidine
Kir-channels can shut down secretion of growth hormone or prolactin from the anterior pituitary (see Bertil Hille: ion channels of excitable membrane) —Preceding unsigned comment added by 141.5.4.128 ( talk) 11:54, 24 April 2008 (UTC)
"Potassium channels are found in most cells, and control the electrical excitability of the cell membrane." Strictly speaking, K+ channels are also expressed in non-excitable cells, such as red blood cells, epithelial cells, endothelial cells, etc. I'm taking the liberty of changing this statement. I also re-organized the page a little, added references to cardiac and pancreatic tissue and added another reference.
These K+ channels are incorrect. Please review recent papers by Roderick MacKinnon, for which he received a Nobel prize for correctly photographing (through x-ray crystallography) a channel and discovering how they truly function, it is much less graceful and elaborate as that which is on this page. (from anon, jan 24)
There seems to be some mistake in the table of potassium channel in the row on inwardly rectifying channels. It doesn't compare to the actual article on inwardly rectifying potassium channels. Reading this, you get the feeling that there is only G-protein-activated and ATP-sensitive kirs. That's not what Inward-rectifier potassium ion channel says. I'm not enough of an expert to know which one is right though. Does anybody know? -- LasseFolkersen ( talk) 09:09, 7 March 2008 (UTC)
The statement (in the section on "Structure") "since sodium ions have greater charge density, they have a larger shell of water molecules surrounding them and thus are more bulky" is technically correct, but it is NOT the correct explanation of why potassium channels are impermeable to sodium. But the next section, "selectivity filter", gives the correct explanation. I suggest deleting this largely irrelevant, and misleading, sentence. 24.47.61.206 ( talk) 03:20, 25 November 2009 (UTC)
There appears to be a conflict in some recent edits over a description of the selectivity filter structure between myself and JamesMilnerWhite (and an IP editor). The description of the region with the selectivity filter has been redefined as a nest (protein structural motif) while previous convention was to call it the P-loop. [1] [2] [3] [4]
I disagree with these edits on based on:
An inclusion of nest in the description of the structure is certainly fair. However, excising the P-loop description is in contradiction to convention within the K-channel field. I propose something like this as a compromise:
Potassium ion channels remove the hydration shell from the ion when it enters the selectivity filter. The selectivity filter is formed by a five residue sequence, TVGYG, termed the signature sequence, within each of the four subunits. This signature sequence is within a loop between the pore helix and TM2/6, historically termed the P-loop. This signature sequence is highly conserved, with the exception that an isoleucine residue in eukaryotic potassium ion channel is often substituted with a valine residue in prokaryotic channels. This sequence adopts a unique main chain structure, structurally analogous to a nest protein structural motif.
Dbsseven ( talk) 18:01, 8 June 2017 (UTC)
References
Hi all, The section on "Muscarinic potassium channel" seems out of place here. For such a general article, a brief but highly specific section on one particular channel subfamily seems out of place. (By analogy, all sorts of other highly medically relevant/interesting channels could have their own subsection here. The BK channel, various Kv-channels...) The content is already available through the GIRK link in the "Types" section.
I would propose removing this section. But since this is a reasonably substantial deletion, I thought worth discussing here. Dbsseven ( talk) 18:35, 9 March 2018 (UTC)
Does this section really meet the inclusion criteria? I'm not really familiar with them which is why I'm not editing it but it really does not feel at all relevant... Anditres ( talk) 06:53, 8 February 2022 (UTC)
This article is rated B-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||||||||||||||||||||||||||||||||||||
|
Blocking agents for potassium channels also are: Cs+,H+,Ba++,Rb+,Sr++,Mg++,Na+,Capsaicin, Noxiustoxin, Chlotrimazol, Spermine, Spermidine
Kir-channels can shut down secretion of growth hormone or prolactin from the anterior pituitary (see Bertil Hille: ion channels of excitable membrane) —Preceding unsigned comment added by 141.5.4.128 ( talk) 11:54, 24 April 2008 (UTC)
"Potassium channels are found in most cells, and control the electrical excitability of the cell membrane." Strictly speaking, K+ channels are also expressed in non-excitable cells, such as red blood cells, epithelial cells, endothelial cells, etc. I'm taking the liberty of changing this statement. I also re-organized the page a little, added references to cardiac and pancreatic tissue and added another reference.
These K+ channels are incorrect. Please review recent papers by Roderick MacKinnon, for which he received a Nobel prize for correctly photographing (through x-ray crystallography) a channel and discovering how they truly function, it is much less graceful and elaborate as that which is on this page. (from anon, jan 24)
There seems to be some mistake in the table of potassium channel in the row on inwardly rectifying channels. It doesn't compare to the actual article on inwardly rectifying potassium channels. Reading this, you get the feeling that there is only G-protein-activated and ATP-sensitive kirs. That's not what Inward-rectifier potassium ion channel says. I'm not enough of an expert to know which one is right though. Does anybody know? -- LasseFolkersen ( talk) 09:09, 7 March 2008 (UTC)
The statement (in the section on "Structure") "since sodium ions have greater charge density, they have a larger shell of water molecules surrounding them and thus are more bulky" is technically correct, but it is NOT the correct explanation of why potassium channels are impermeable to sodium. But the next section, "selectivity filter", gives the correct explanation. I suggest deleting this largely irrelevant, and misleading, sentence. 24.47.61.206 ( talk) 03:20, 25 November 2009 (UTC)
There appears to be a conflict in some recent edits over a description of the selectivity filter structure between myself and JamesMilnerWhite (and an IP editor). The description of the region with the selectivity filter has been redefined as a nest (protein structural motif) while previous convention was to call it the P-loop. [1] [2] [3] [4]
I disagree with these edits on based on:
An inclusion of nest in the description of the structure is certainly fair. However, excising the P-loop description is in contradiction to convention within the K-channel field. I propose something like this as a compromise:
Potassium ion channels remove the hydration shell from the ion when it enters the selectivity filter. The selectivity filter is formed by a five residue sequence, TVGYG, termed the signature sequence, within each of the four subunits. This signature sequence is within a loop between the pore helix and TM2/6, historically termed the P-loop. This signature sequence is highly conserved, with the exception that an isoleucine residue in eukaryotic potassium ion channel is often substituted with a valine residue in prokaryotic channels. This sequence adopts a unique main chain structure, structurally analogous to a nest protein structural motif.
Dbsseven ( talk) 18:01, 8 June 2017 (UTC)
References
Hi all, The section on "Muscarinic potassium channel" seems out of place here. For such a general article, a brief but highly specific section on one particular channel subfamily seems out of place. (By analogy, all sorts of other highly medically relevant/interesting channels could have their own subsection here. The BK channel, various Kv-channels...) The content is already available through the GIRK link in the "Types" section.
I would propose removing this section. But since this is a reasonably substantial deletion, I thought worth discussing here. Dbsseven ( talk) 18:35, 9 March 2018 (UTC)
Does this section really meet the inclusion criteria? I'm not really familiar with them which is why I'm not editing it but it really does not feel at all relevant... Anditres ( talk) 06:53, 8 February 2022 (UTC)