Sir Andrew Fielding Huxley

1917-

English Physiologist

Sir Andrew Fielding Huxley received the Nobel Prize in medicine for his work on the chemical properties of nerve and muscle impulses. This work has influenced and furthered research into nerve disorders and brought insight into how the brain works.

Andrew Huxley was born in London on November 27, 1917. He had two brothers, Julian (1887-1975), a well-known scientist, and Aldous (1894-1963), author of the classic novel Brave New World. Andrew came from a long lineage of scientists and writers. Both his father and grandfather had strong science backgrounds and introduced the young Huxley to their enthusiasm for creative thinking, scientific research, and writing. Being mechanically minded, he enjoyed building and using microscopes throughout his secondary school years.

Interestingly, Huxley entered Cambridge University's Trinity College with the intent to study literature. He changed his focus from literature to the sciences in 1932. He assumed that he would concentrate on the physical sciences, physics in particular. However, students were required to take another science course at Trinity. After some contemplation, he chose physiology, on the recommendation of friends. The department had exciting professors, he enjoyed the subject matter, and at the completion of the course decided to study for entrance into medical school.

While studying anatomy and physiology he joined his colleague Alan Hodgkin (1914- ) at the Marine Biology Laboratory for his first introduction to research and the first of their collaborative projects. Hodgkin had been conducting research into the nerve fibers of crabs and the recently discovered giant nerve fibers in squids. He wanted to understand the mechanism by which the action potential travels along the nerve fiber. The action potential is the electrical change that activates the nerve impulse. Together Huxley and Hodgkin recorded the first electrical impulses from the nerve cells of the giant squid. The large size of the cells permitted the insertion of electrodes directly into the interior of the cells. Before Huxley and Hodgkin's experiment, no one had succeeded in recording the electrical impulse from inside the nerve fiber. They had conclusive evidence that the electrical impulse is caused by selective changes in the permeability of the cell membrane.

He returned to Trinity to continue his medical training, but the entrance of Britain into World War II curtailed all clinical training. Because all medical teaching was suspended due to air attacks, he spent the rest of the war working on gunnery research for various branches of the armed services. After the war he completed his science studies and was appointed to the faculty of Trinity College in the Department of Physiology. There Huxley and Hodgkin resumed their research collaboration, focusing on nerve conduction and nerve fibers.

In 1963 Huxley, Hodgkin, and John Eccles (1903-1997) received the Nobel Prize in medicine for continued research into the transmission of nerve impulses. This information, transmitted by action potentials, is specified by the frequency of transmission and by the connections each nerve cell has with neighboring cells. During the rising phase of the impulse, the membrane becomes permeable, and this permeability is highly specific for sodium ions. The pores in the membrane open up as a result of the potential change and let sodium ions diffuse in, bringing the potential very nearly to the equilibrium of the sodium ions. During the falling phase of the impulse, potassium ions diffuse out.

With a judicious combination of electrochemistry, modern electronics, and mathematical modeling, Huxley's team was able to show that the exchange of sodium and potassium ions causes a brief reversal in a nerve cell's electrical polarization; this phenomenon, known as an action potential, results in the transmission of an impulse along a nerve fiber. The techniques that they developed have been applied with minor modifications to other excitable tissues for all subsequent research to understand the function of the central nervous system. Huxley was knighted in 1974.

LESLIE HUTCHINSON