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The K+ Channel, A New Hope For a Better Understanding

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The K+ Channel, A New Hope For a Better Understanding

The axons of our neurons are the pathway for the communication that exists in our nervous system. This communication takes the form of an electric signal, also called an action potential. The action potential occurs due to a change in voltage across the membrane of the axon. The change in voltage is achieved by a change in the concentrations of the ions, Na+, Ca+, and K+(1) . The cell starts with a large concentration of potassium ions, K+, inside the cell, and a large concentration of sodium ions, Na+, outside the cell. The action potential propagates down the axon due to openings and closing of different channels allowing changing of the concentrations of the ions(10).

Channels are proteins that span the membrane of the axon. These proteins have a structure so that they can be allow ions to flow through pores that are only open at the appropriate times. Some of the channels are opened and closed by other chemicals, while some are initiated by a change in the membrane potential.

This particular K+ channel, which is greatly studied, is a voltage-gated channel. This means that the channel opens in response to a certain voltage difference that occurs across the membrane. The channel is closed when the cell is at rest. Following inactivation the channel opens via a complicated mechanism, which scientists are still trying to decipher(7)(8). The specific voltage is that which occurs after the Na+ channel has opened and allowed a significant amount of Na+ to be released from the cell. So, the K+ channel is induced to an open state by a depolarization of the membrane potential. The K+ channel opens at the beginning of the repolarization, or after the depolarization has alm...

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...eprint/27/2/423

6)Reconstructing Voltage Sensor-Pore Interaction from a Fluorescence Scan of a Voltage-Gated K+ Channel

http://serendip.brynmawr.edu/bb/neuro/neuro02/web1/www.neuron.org/cgi/content/reprint/27/3/585

7)Tight Steric Closure at the Intracellular Activation Gate of a Voltage-Gated K+ Channel.

http://serendip.brynmawr.edu/bb/neuro/neuro02/web1/www.neuron.org/cgi/content/full/32/4/649

8)The Polar T1 Interface Is Linked to Conformational. Changes that Open the Voltage-Gated Potassium Channel

http://www.cell.com/content/article/abstract?uid=PIIS009286740000088X

9)Visual of the K+ Channel

http://www.neuron.org/content/article/abstract?uid=PIIS0896627300809046&imageid=GR1

10)Lights, Camera, Action Potential, A site made for children that has great descriptions and visuals of an action potential.

http://faculty.washington.edu/chudler/ap.html
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