Obituary: Sir Bernard Katz (original) (raw)

World renowned for his investigation of the biochemistry of the nervous system and of the function of the mysterious pineal gland in the brain, Sir Bernard Katz, who has died aged 92, was one of the brilliant young German physiologists who sought sanctuary in Britain after Adolf Hitler came into power in his homeland in 1933.

Katz's discovery in the 1950s of the "quantum" character of nerve junction biochemistry transformed scientific perception of the nature of signal processing in the nervous system. For this work he received a knighthood in 1969 and, in 1970, shared the Nobel Prize for physiology of medicine with Julius Axelrod of America and Ulf von Euler of Sweden.

Katz carried out fundamental research on the nature of the chemical-electrical transmission of nerve impulses across the "gaps" at nerve junctions. Much of this initial work was done under the 1922 Nobel Laureate for physiology of medicine, Professor AV Hill at University College London (UCL), whom Katz joined as a postgraduate in 1935.

By the 1950s, unravelling the regulation and transmission of nerve impulses and the biochemistry of hormones controlling brain function had become key areas of research. Two major extrinsic factors were driving this forward: the need to understand the effects on the central nervous system of organochlorine and organophosphorus compounds, the basis of nerve gases and the emerging pest control compounds; and the possibility that detailed understanding would bear rewards in new areas of medicine.

Medical optimism was rather prematurely emphasised in the 1970 Nobel citation delivered by Professor Uvnas of the Karolinska Institute. "It is my belief that in the near future this research on chemical transmission will lead to a better understanding of the intimate nature of mental disease and psychical disturbances. Through these new ways treatment will be opened." While Axelrod and von Euler worked primarily on the role and storage of noradrenalin as a transmitter substance at nerve ends, Katz studied the biochemical cycle in neuromuscular function of acetylcholine, a substance whose role as a neuro-transmitter had been confirmed in the 1930s by Sir Henry Dale and his colleagues.

Lethal paralysis resulting from the blocking of the acetylcholine cycle is one of the effects of organophosphorus nerve agents. The choice made by Katz in the immediate postwar years was influenced strongly by the department head, Professor Hill, who was not only a great physiologist but also served as wartime cabinet scientific adviser under Winston Churchill and remained an informal adviser in Whitehall's corridors of governmental power for many years. Uppermost among the mysteries of neural signal transmission was how discrete electrical impulses travelling along a nerve fibre as a sequence of similar "spikes" whose frequency related directly to their resulting physical function could somehow cross the large gap observed at each nerve junction, very quickly and without being changed. Dale had shown that transmission could not be electrical and that acetylcholine was involved. Katz unravelled the detailed biochemistry of the dynamic cycle that carries signals across the gap in the wiring between nerve endings and the "effector" cells in muscle which they control.

Katz's contribution was built upon the work of many other scientists, but he unravelled the central role of acetylcholine and its key enzymes, going on to show that even when a nerve is inactive, the acetylcholine cycle at junctions continues to tick over, transmitting a tiny reassurance bleep that tells the system that the connections are working. His major discovery was that this "resting" signal depends, not on individual molecules, but on the release of small packets (quanta) of transmitter substance, each of several thousand molecules. When these cross the junction after release from cellular storage vesicles, they release a capacitor-like electrical signal stored on the opposite side of the gap. The underlying enzyme cycle, involving production and inactivation of transmitter substances crucial to normal nerve function, was revealed as highly vulnerable to disruption.

Katz went on to show that the single "packet" of molecules, characteristic of the resting signal, is the minimum amount that can produce a corresponding signal in the receiving nerve cell. As signal strength rises through increased frequency of impulses, this is mirrored rapidly by a stepwise increase in the release of acetylcholine packets across the junction. Katz proved the first perception of neural function at the molecular interaction level, the basis of modern psychopharmacology.

In his later years, Katz sought to unravel the biochemistry of the pineal gland, investigating in particular the biochemical mechanism leading to the production of melatonin, first identified in the pineal gland in 1948. In frogs and other amphibia the pineal acts as a third eye, responding directly to light and controlling skin colour and several other functions. In humans, however, its role remains obscure.

With others, Katz showed that in some mammals pineal production of melatonin is triggered indirectly by light by means of signals from the retina. Like others, he was unable to demonstrate the biochemical pathways of the pineal's apparent role in early sexual development, in circadian rhythms and in subjective brain function such as mood. However, his interest in brain function and its control remained with him throughout his life.

Katz's schooling was at the Albert Gymnasium in Leipzig. He then went on to the University of Leipzig, where he graduated in medicine in 1934. In 1935, he left Germany because the Russian-Jewish origin of his family meant certain persecution under the Nazi regime. He chose AV Hill's laboratory at UCL because of its strong research tradition in physiology, particularly in muscle structure and function.

In 1938, after gaining his PhD, he was awarded a Carnegie Fellowship in Australia as a medical research fellow at Sydney Hospital under Sir John Eccles. There he stayed until 1942. Naturalised in 1941, he joined the Royal Australian Air Force in 1942 and, until the end of the war, he worked on radar in the south-west Pacific.

Shortly before returning to Hill's laboratory at UCL in 1947 as assistant director of research, he married Marguerite Penly from Cremone, New South Wales. In the immediate postwar era, although based at UCL, Katz spent much of his time working at Cambridge and at the Marine Laboratory, Plymouth, with Sir Alan Hodgkin and Sir Andrew Huxley. They were then engaged in research that unravelled the electrochemical transmission of signals within squid nerve fibres, for which they shared the 1963 Nobel Prize for physiology of medicine.

The Hodgkin-Huxley work on signal transmission in the giant nerve axon of the squid had been made possible by the work of the outstanding British physiologist JZ Young, carried out - like that of Henry Dale - in the 1930s. All the stars in the brilliant postwar neurophysiology group in Britain, of which Katz was a member, were thus truly apprentices to earlier genius.

Katz was reader in physiology at UCL from 1950 to 1951. He became professor of biophysics and head of the biophysics department at the college in 1952. He was to remain there until 1978, when he became emeritus professor and honorary research fellow.

His publications included Electric Excitation Of Nerve (1939), Nerve Muscle And Synapse (1966) and The Release Of Neural Transmitter Substances (1969). Among awards from America, Germany, Japan and many other parts of the world, he received the Royal Society's coveted Copley Medal in 1967. He was the biological secretary and a vice president of the Royal Society from 1968 to 1976 and, after his retirement in 1974, remained active in research council and other science administration.

Katz was an intense and intensely private man who played life like a game of chess, a game that, characteristically, he played fiercely and remarkably well. His wife predeceased him in 1999. He is survived by their two sons.

· Bernard Katz, biophysicist, born March 26 1911; died April 23 2003

This obituary has been revised and updated since the author's death in 1998