Experiments

In Chapter 6, we discussed the basic membrane mechanisms underlying the generation of the action potential in a neuron. We saw that all the properties of the action potential could be explained by the actions of voltage-sensitive sodium and potassium channels in the plasma membrane, both of which behave as though there are voltage-activated gates that control permeation of ions through the channel. In this chapter, we will discuss the experimental evidence that gave rise to this scheme for explaining the action potential. The fundamental experiments were performed by Alan L. Hodgkin and Andrew F. Huxley in the period from 1949 to 1952, with the participation of Bernard Katz in some of the early work. The Hodgkin-Huxley model of the nerve action potential is based on electrical measurements of the flow of ions across the membrane of an axon, using a technique known as voltage clamp. We will start by describing how the voltage clamp works, and then we will discuss the observations Hodgkin and Huxley made and how they arrived at the gated ion channel model discussed in the last chapter.

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