Eccles, Sir John Carew

▪ 1998

      Australian neurophysiologist (b. Jan. 27, 1903, Melbourne, Australia—d. May 2, 1997, Contra, Switz.), discovered many aspects of the vertebrate nervous system, notably how nerve impulses are transmitted between neurons, or nerve cells, work for which he shared the 1963 Nobel Prize for Physiology or Medicine with Alan L. Hodgkin and Andrew F. Huxley. Eccles's prizewinning research showed that one neuron communicates with a closely adjacent neuron by releasing chemicals into the synapse, the narrow space between the two cells. The chemicals, called neurotransmitters, cross the synapse and bind to the second cell, either activating or inhibiting it. His findings resolved a long-standing debate over whether nerve cell communication occurs through chemical or electrical means. Eccles studied biology and medicine at Melbourne University (M.B. and B.S; 1925), where he qualified for a Rhodes scholarship. At the University of Oxford, he studied with leading neurophysiologist Sir Charles Scott Sherrington. After graduating (1929; Ph.D.) Eccles taught and conducted research at Oxford until 1937, when he returned to Australia to become director of the Kanematsu Memorial Institute of Pathology, Sydney. During World War II he was a medical consultant to the Australian army. Eccles then served (1944-51) as professor of physiology at the University of Otago, Dunedin, N.Z., before heading (1952-66) the physiology department at the Australian National University, Canberra. Facing mandatory retirement, he left Australia and continued his work (1966-68) at the Institute for Biomedical Research, Chicago, and the State University of New York at Buffalo, where he was distinguished professor of physiology (1968-75). He was elected (1941) to the Royal Society of London and received (1962) the Royal Medal. He served as president of the Australian Academy of Science (1957-61) and was knighted in 1958. In addition to the more than 500 scientific papers that he published, Eccles was the author of a number of books, including the purely scientific The Physiology of Nerve Cells (1957) and the philosophical Facing Reality: Philosophical Adventures by a Brain Scientist (1970).

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▪ Australian physiologist

born Jan. 27, 1903, Melbourne, Australia

died May 2, 1997, Contra, Switz.

 Australian research physiologist who received (with Alan Hodgkin (Hodgkin, Sir Alan) and Andrew Huxley (Huxley, Sir Andrew Fielding)) the 1963 Nobel Prize for Physiology or Medicine for his discovery of the chemical means by which impulses are communicated or repressed by nerve cells (neurons (neuron)).

      After graduating from the University of Melbourne in 1925, Eccles studied at the University of Oxford under a Rhodes scholarship. He received a Ph.D. there in 1929 after having worked under the neurophysiologist Charles Scott Sherrington. He held a research post at Oxford before returning to Australia in 1937, teaching there and in New Zealand over the following decades.

      Eccles conducted his prizewinning research while at the Australian National University, Canberra (1951–66). He demonstrated that one nerve cell communicates (action potential) with a neighbouring cell by releasing chemicals into the synapse (the narrow cleft, or gap, between the two cells). He showed that the excitement of a nerve cell by an impulse causes one kind of synapse to release into the neighbouring cell a substance (probably acetylcholine) that expands the pores in nerve membranes. The expanded pores then allow free passage of sodium ions into the neighbouring nerve cell and reverse the polarity of electric charge. This wave of electric charge, which constitutes the nerve impulse, is conducted from one cell to another. In the same way, Eccles found, an excited nerve cell induces another type of synapse to release into the neighbouring cell a substance that promotes outward passage of positively charged potassium ions across the membrane, reinforcing the existing polarity and inhibiting the transmission of an impulse. (See also action potential.)

      Eccles's research, which was based largely on the findings of Hodgkin and Huxley, settled a long-standing controversy over whether nerve cells communicate with each other by chemical or by electric means. His work had a profound influence on the medical treatment of nervous diseases and research on kidney, heart, and brain function.

      Among his scientific books are Reflex Activity of the Spinal Cord (1932), The Physiology of Nerve Cells (1957), The Inhibitory Pathways of the Central Nervous System (1969), and The Understanding of the Brain (1973). He also wrote a number of philosophical works, including Facing Reality: Philosophical Adventures by a Brain Scientist (1970) and The Human Mystery (1979).

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