John Carew Eccles was a neurophysiologist whose research explained how nerve cells communicate with one another. He demonstrated that when a nerve cell is stimulated it releases a chemical that binds to the membrane of neighboring cells and activates them in turn. He further demonstrated that by the same mechanism a nerve cell can also inhibit the electrical activity of nearby nerve cells. For this research, Eccles shared the 1963 Nobel Prize for Physiology or Medicine with Alan Lloyd Hodgkin and Andrew Huxley.
Born on January 27, 1903, in Melbourne, Australia, Eccles was the son of William James and Mary Carew Eccles. Both of his parents were teachers, and they taught him at home until he entered Melbourne High School in 1915. In 1919, Eccles began medical studies at Melbourne University and graduated in 1925 with the highest academic honors. Eccles' academic excellence was rewarded with a Rhodes Scholarship, which allowed him to pursue a graduate degree in England at Oxford University. In September 1925, Eccles began studies at Magdalen College, Oxford. Eccles received high honors for science and was named a Christopher Welch Scholar. In 1927, he received appointment as a junior research fellow at Exeter College, Oxford.
The following year, after becoming a junior fellow, Eccles became a research assistant to the world's leading neurophysiologist, Charles Scott Sherrington, who would win the Nobel Prize in 1932. Although Sherrington was then nearly 70 years old, Eccles collaborated with him on some of his most important research. Together, they studied the factors responsible for inhibiting a neuron, or a nerve cell. They also explored what they termed the "motor unit"--a nerve cell which coordinates the actions of many muscle fibers. For this work on neural excitation and inhibition, Eccles was awarded his doctorate in 1929.
Eccles remained at Exeter after receiving his doctorate, serving as a Staines Medical Fellow from 1932 to 1934. During this period, he also held posts at Magdalen College as tutor and demonstrator in physiology. The research that Eccles had begun in Sherrington's laboratory continued as Eccles became increasingly interested in explaining the process that underlies inhibition. He and other neurophysiologists believed that the transmission of electrical impulses was responsible for neural inhibition. Bernhard Katz and Paul Fatt later demonstrated, however, that it was a chemical mechanism and not a wholly electrical phenomenon which was primarily responsible for inhibiting nerve cells.
In 1937, Eccles returned to Australia to assume the directorship of the Kanematsu Memorial Institute for Pathology in Sydney. During the late 1930s and early 1940s, the Kanematsu Institute, under his guidance, became an important center for the study of neurophysiology. With Katz, Stephen Kuffler, and others, he undertook research on the activity of nerve and muscle cells in cats and frogs, studying how nerve cells communicate with muscle or motor cells. His team proposed that the binding of a chemical (now known to be the neurotransmitter, acetylcholine) by the muscle cell led to a depolarization, or a loss of electrical charge, in the muscle cell. This depolarization, Eccles believed, occurred because charged ions in the muscle cell were released into the exterior of the cell when the chemical substance released by the nerve cell was bound to the muscle cell.
During World War II, Eccles served as a medical consultant to the Australian army, where he studied vision, hearing, and other medical problems faced by pilots. Returning to full-time research and teaching in 1944, Eccles became professor of physiology at the University of Otago in Dunedin, New Zealand. At Otago, Eccles continued the research that had been interrupted by the war, but now he attempted to describe in greater detail the neural transmission event, using very fine electrodes made of glass. This research continued into the early 1950s, and it convinced Eccles that transmission from nerve cell to nerve cell or nerve cell to muscle cell occurred by a chemical mechanism, not an electrical mechanism as he had thought earlier.
In 1952, Eccles left Otago for the Australian National University in Canberra. Here, along with Fatt and J. S. Coombs, he studied the inhibitory process in postsynaptic cells, which are the nerve or muscle cells that are affected by nerve cells. They were able to establish that whether nerve and muscle cells were excited or inhibited was controlled by pores in the membrane of the cells, through which ions could enter or leave. By the late 1950s and early 1960s, Eccles had turned his attention to higher neural processes, pursuing research on neural pathways and the cellular organization of the brain.
In 1966, Eccles turned 63 and university policy at the Australian National University required him to retire. He then accepted an invitation from the American Medical Association to become the director of its Institute for Biomedical Research in Chicago. He left that institution in 1968 to become professor of physiology and medicine and the Buswell Research Fellow at the State University of New York in Buffalo. The university constructed a laboratory for him where he could continue his research on transmission in nerves. In 1975, he retired from SUNY with the title of Professor Emeritus, subsequently moving to Switzerland.
Eccles' memberships included the Royal Society of London, the Royal Society of New Zealand, and the American Academy of Arts and Sciences. He was awarded the Gotch Memorial Prize in 1927, and the Rolleston Memorial Prize in 1932. The Royal College of Physicians presented him with their Baly Medal in 1961, the Royal Society gave him their Royal Medal in 1962, and the German Academy awarded him the Cothenius Medal in 1963. Also in 1963, he shared the Nobel Prize for Physiology and Medicine with Alan Hodgkin and Andrew Huxley. He was knighted in 1958. He died at his home in Contra, Switzerland in 1997.
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