Sir John Carew Eccles

Sir John Carew Eccles
(1903)


Australian research physiologist, who in 1963 received (with Alan Hodgkin and Andrew Huxley) 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.
After graduating from the University of Melbourne in 1925, Eccles studied at the University of Oxford under a Rhodes scholarship. He received his Ph.D. there in 1929 after having worked under the neurophysiologist Charles Scott Sherrington. After holding a research post at Oxford, Eccles returned to Australia in 1937, teaching there and in New Zealand over the following decades.

Working at the Australian National University, Canberra (1951-66), Eccles 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 he found that 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' work, based largely on the findings of Hodgkin and Huxley, had a profound influence on the medical treatment of nervous diseases and research on kidney, heart, and brain function.

Among his books are Reflex Activity of the Spinal Cord (1932), The Physiology of Nerve Cells (1957), The Inhibitory Pathways of the Central Nervous System (1969), The Understanding of the Brain (1973), and The Human Psyche (1980).