The K+ Channel RevisitedMany scientists enter the field of neuroscience with a desire to understand how the human brain functions to create our actions. Some take a large approach and study reactions to stimulus in live animals. This approach leaves us still wanting to know about things that aren’t a result of an outside stimulus. Other scientists take the minimalist approach and start by studying the exact mechanisms of individual cells of the brain. But, what good does that do us for everyday life? There is also the approach of taking our knowledge of behavior from diseases of the brain. Would we have thought about how our brain regulates our moods if it weren’t for the fact that some people experience depression, in which the regulation of mood goes amiss? Many of the disease have led us to a deep understanding of the chemical interactions in our brain and body. At a very broad level, and ignoring religious discussions, we can say that every part of our existence is a result of chemical interactions. Besides giving us our substance, chemistry also gives us a mode of communication throughout our bodies. In our brain a large chemical component is that of the action potential that is conducted along a neuron as a result in the changing permeability of the cell.
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 permeability of the neurons to 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 permeability to the differing 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.