Sir Andrew Huxley, a British scientist from an illustrious family whose boyhood mechanical skills led to a career in physiology — “the mechanical engineering of living things,” he called it — and a Nobel Prize for explaining the electrical basis of bodily movement, died on Wednesday. He was 94.
His death was announced by Cambridge University’s Trinity College, where he had served as master from 1984 to 1990.
Professor Huxley, a half brother of the novelist Aldous Huxley, shared the 1963 Nobel in Physiology or Medicine with his collaborator and former teacher, Sir Alan Hodgkin of Britain, and Sir John Eccles of Australia for explaining how nerve cells transmit electrical signals to control every bodily action and sensation.
Professor Huxley and Professor Hodgkin’s work further explained how anesthesia works, laid the groundwork for devices that operate prosthetic limbs, and led to the identification of certain genetic diseases.
The two specifically explained how electricity travels the length of a single nerve cell, while Dr. Eccles described how the impulse jumps from one nerve cell to the next.
Their research solved a mystery dating from 1771, when the Italian physicist Luigi Galvani zapped the leg of a dead frog with electricity, making it twitch. Movement required electricity, but how did electrical current pulse through living things?
Professor Huxley and Professor Hodgkin ran experiments using a nerve cell extracted from a squid. The nerve cell, known as the giant axon, is the largest found in any species, running the entire length of the creature. The researchers threaded the long, stringy axon with an electrode and measured the changes in voltage as a current swept the nerve.
Based on their measurements, they proposed that electrically charged atoms called ions moved through hinged gates in the cell membrane to generate electricity. First sodium ions entered the axon through one gate, and then potassium ions exited through another.
Through this flux of ions, the electrical impulse propagated itself along the length of the axon, transmitting signals for action, thought, sight or touch from one end of the nerve to the other, they said.
No instrument at the time was capable of detecting the ion gates. So to test their explanation, the scientists devised a series of equations to see if the laws of physics could predict the voltage changes they had seen in their squid experiments. Most of the number crunching fell to Professor Huxley, a mathematical whiz. His results closely matched their research data, suggesting that their theory was correct.
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