Andrew Huxley (Nov 22, 1917 – May 30, 2012): An Appreciation.
• You may be familiar with his name. Although he was grandson to Thomas Huxley (“Darwin’s Bulldog”) and half-brother to Julian Huxley (evolutionary biologist, founding member of WWF) and author Aldous Huxley (“Brave New World”), Andrew Huxley is famous in my field of ion channel research for explaining how nerves conduct electrical signals.
• 1n 1939, together with Alan Hodgkin, he inserted an electrode into the giant nerve of a squid. It was known that at rest, potassium ions (K+) moved out of the cell leaving the inside more negative than the outside by about 65 millivolts. When stimulated, the nerve would fire an action potential, lasting only a fraction of a millisecond. They captured the voltage changes during this fleeting action potential, showing that the charge difference reversed to positive inside the cell. Next, by diluting the sea water bathing the nerve, they showed this inward current was due to movement of sodium ions (Na+) into the nerve cell. Today, we know that these currents are carried by sequential opening and closing of ion channels. What is a squid giant axon? Watch this first: http://www.youtube.com/watch?v=omXS1bjYLMI
Next, watch a re-enactment of their classic experiment and famous voltage clamp technique (ask me questions, I teach this) : http://www.youtube.com/watch?v=k48jXzFGMc8
• Although their work was interrupted by WWII, during which Huxley turned his hands to radar and psychiatry, the two colleagues got back together in Cambridge, in 1946. They solved the set of simultaneous equations, using a postwar computing machine, to describe the ionic theory of nerve impulses. The Hodgkin-Huxley model laid the foundation for understanding how the nervous system works. For this, they received the Nobel prize in 1963.
• Huxley stumbled into Physiology by accident- he was hoping to be a physicist. “I had to do a third science, as well as the obvious subjects of maths, physics and chemistry. A chum of mine a few years older told me that physiology was a most vital subject, and I would be learning things that were still controversial.” What a perfect segue into electrophysiology!