potassium leaky channels

[idrees_agha86]

what is the reason that the potassium leaky channels do not close?They remain open all the time,during resting membrane potential and even during action potential.

[ecoli]

I believe there are other channels to balance out the charges. Unlike most cells, heart node cells are activated by hyperpolarization, rather than depolarization.

[pioneer]

The Na+ ion is what is called a kosmotrope and K+ ion is what is called a chaotrope. What that means is Na+ will create order in water (cosmos) and K+ will create disorder (chaos) in water. The effect of this ionic associated water extends to nearby proteins such as channels. The K+ and its chaotropic affect on water cause these channels to looser, so they leak. The Na+ ion is smaller, but because it brings its ordered water, the channel tightens up like a frog's butt being by chased by a snake.

 

This water affect is also required for the energetics of the sodium pumps. The Na+ needs to be on the inside and the K+ on the outside to work. The K+ on the outside loosens up the butt end of the pump. Although the Na+ tightens the mouth, its structured water is needed to account of the energetics that allow the ATP reaction to occur. If we switch chaotrope and kosmotrope the energy doesn't add up properly and you get a dud.

[jimmydasaint]

I first thought that the answer was to refer to the simple textbook answer:

 

Neurons, like all cells, maintain different concentrations of certain ions across their cell membranes. Imagine the case of a boat with a small leak below the water line. In order to keep the boat afloat, the small amount of water entering through the leak has to be pumped out, which maintains a lower water level relative to the open sea. Neurons do the same thing, but they pump out positively charged sodium ions. In addition, they pump in positively charged potassium ions (potash to the gardeners out there!!) Thus there is a high concentration of sodium ions present outside the neuron, and a high concenttration of potassium ions inside. The neuronal membrane also contains specialised proteins called channels, which form pores in the membrane that are selectively permeable to particular ions. Thus sodium channels allow sodium ions through the membrane while potassium channels allow potassium ions through.

 

http://www.bristol.ac.uk/synaptic/public/basics_ch1_2.html

 

Then I saw the word 'why?'. After a bit of searching and reading, I came up with the following paper and this can provide you with a basis for further research and reading :

 

Leak K+ currents contribute to the resting membrane potential and are important for modulation of neuronal excitability. Within the past few years, an entire family of genes has been described whose members form leak K+ channels, insofar as they generate potassium-selective currents with little voltage- and time-dependence. They are often referred to as "two-pore-domain" channels because of their predicted topology, which includes two pore-forming regions in each subunit. These channels are modulated by a host of different endogenous and clinical compounds such as neurotransmitters and anesthetics, and by physicochemical factors such as temperature, pH, oxygen tension, and osmolarity. They also are subject to long-term regulation by changes in gene expression. In this review, the authors describe multiple roles that modulation of leak K+ channels play in CNS function and discuss evidence that members of the two-pore-domain family are molecular substrates for these processes.

 

http://nro.sagepub.com/cgi/content/short/9/1/46

 

The emphasis is my own but, suffice to say, nothing in biology seems to be simple. Good luck with your reading.