World of Scientific Discovery on Alan Lloyd Hodgkin and Andrew Fielding Huxley
Hodgkin was born in Banbury, Oxfordshire, England, on February 5, 1914. His father died during World War I, leaving his mother to raise Alan and two younger children. After attending local schools in Malvern and Holt, Hodgkin entered Trinity College, Cambridge, in 1932. After graduation in 1936, he became a fellow of Trinity College.
While at Cambridge, Hodgkin came into contact with some of the world 's leading researchers in neurology, including Edgar D. Adrian and Archibald Vivian Hill. He soon became interested in the question of how nerve messages are transmitted. Due to the efforts of physiologists such as Julius Bernstein (1839-1917), scientists had known for more than a century that the transmission of nerve impulses is somehow correlated with small electrical currents in the body. Beginning in the late 1930s, Hodgkin pursued a line of research that allowed him to clarify the precise nature of this relationship. Some of Hodgkin's most important work concerning nerve impulses was carried out with Andrew Huxley, whom Hodgkin met at the close of World War II.
Andrew Fielding Huxley was born in London on November 22, 1917. The grandson of biologist Thomas Huxley (1825-1895), Andrew attended Cambridge University, where he received his M.S. in 1941. After serving in World War II, he returned to Cambridge, where he began his collaboration with Hodgkin. They chose to study nerve impulses using the nerve cells of the squid, which may be as much as.003 in. (1mm) in diameter, much larger than those of other animals and hundreds of times larger than human neurons. They developed a method for removing single neurons from a squid and maintaining them in a saline solution. This allowed a researcher to insert microelectrodes into the neuron to measure current changes and micropipettes to measure chemical changes within the neuron.
Over a 15-year period, Hodgkin (working with Huxley, Bernard Katz, and others) was able to elucidate the chemical and physical changes that occur along a neuron as it carries a nerve impulse. Those changes primarily involve the movement of sodium and potassium ions across the neural membrane.
In its resting state, the neuron contains an excess of potassium ions within the cell and an excess of sodium ions outside the cell membrane. This difference in ion concentrations results in a small potential difference across the cell membrane, a potential difference that can be measured with a microelectrode. The potential difference is maintained in the cell because the neural membrane does not allow the passage of ions back and forth into and out of the cell.
In a long series of experiments, Hodgkin and his colleagues were able to show that the potential difference and sodium ion concentration along a nerve cell both change at the same time as an impulse moves along the neuron. They were able to explain how this change occurs. As an impulse reaches any particular point in the neuron, the membrane at that point becomes more permeable, allowing sodium ions to flow into and, shortly thereafter, potassium ions to flow out of, the neuron. As the impulse passes that particular point, sodium and potassium ions flow back out of and into the cell, restoring its original potential difference. Hodgkin and Huxley shared the 1963 Nobel Prize for physiology or medicine for their work on the mechanics of nerve transmission.
Like most scientists of his age, Hodgkin had to interrupt his research during World War II while he worked on the development of radar systems. After the war, he returned to Cambridge, where he spent the rest of his academic career. He was appointed Foulerton Research Professor of the Royal Society in 1952 and John Humphrey Plummer Professor of Biophysics in 1970.
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