Bernard Katz English biophysicist and physiologist, Nobel Prize laureate 1970. Date of Birth: 24.03.1911 Country: Great Britain

1. Biography of Bernard Katz
2. Escape from Nazi Germany and Move to England
3. War Service and Research on Synaptic Transmission
4. Discoveries on Neurotransmitters and Nobel Prize
5. Achievements and Honors

Biography of Bernard Katz

Bernard Katz was an English biophysicist and physiologist, and the recipient of the 1970 Nobel Prize. He was born in Leipzig, Germany, to Eugenie Katz (Rabinovich) and Max Katz. After completing his education at Albert Gymnasium in 1929, Katz enrolled at Leipzig University to study medicine. During his time at the university, he became particularly interested in the functions and electrical properties of nerve cells. In 1933, a year before receiving his medical degree, Katz was awarded the Siegfried Garten Prize for his physiological research.

Escape from Nazi Germany and Move to England

With the rise of Hitler and the Nazi regime, Jewish individuals like Katz were being expelled from universities, research labs, and other institutions. Fearing for his safety, Katz decided to leave Germany and moved to England in 1935. He continued his research in neurophysiology at the University of London under the guidance of Archibald V. Hill, and in 1938, he obtained his doctorate.

War Service and Research on Synaptic Transmission

As World War II loomed, Katz accepted an offer from John C. Eccles to move to Australia, where he would be safe. He worked at a hospital in Sydney and became a citizen of the British Commonwealth in 1941. However, when the threat of Japanese invasion arose, Katz joined the Royal Australian Air Force and served as a radar officer in the Pacific region until the end of the war.

In the early 1940s, Katz, along with Eccles and their colleague Stephen Kuffler, studied the transmission of excitation from nerve cells to muscle fibers. Prior to World War I, most neurophysiologists believed that nerve cells excite muscle fibers or other nerve cells through direct electrical interactions, similar to how electrical impulses propagate within individual nerve cells. However, the research conducted by Otto Loewi and Henry H. Dale in the 1920s and early 1930s demonstrated that excitation is transmitted through synapses, which are specialized structures where excitation passes from one nerve fiber to another or from a nerve fiber to a muscle fiber or another cell, through the action of chemical mediators.

Among the researchers who adhered to the electrical theory of synaptic transmission, Eccles remained the most prominent and consistent until the investigations by Katz and Kuffler on the effects of chemical substances on transmission in the neuromuscular synapse. After the conclusion of World War II, Eccles moved to New Zealand, where he conducted experiments that definitively disproved his own hypothesis. Katz, on the other hand, returned to London in 1946 and resumed his work in Hill's laboratory at University College. Although Katz was well-versed in electrophysiological methods for studying nerve cells, he lacked expertise in biochemistry. Therefore, he temporarily ceased his investigations on the chemical processes in synapses and joined the studies of Alan Hodgkin and Andrew Huxley, who were examining the properties of action potentials in individual nerve cells. The scientists discovered that this process is controlled by purely biophysical laws.

Discoveries on Neurotransmitters and Nobel Prize

In 1950, Katz returned to his research on the neuromuscular junction and, together with his colleague Paul Fatt, applied new techniques to record electrical impulses in individual neurons. They were interested in the electrical activity of the end plates of muscle fibers, which they recorded directly through the synapse formed by the nerve ending. By that time, Dale had established that this activity arises from the release of the neurotransmitter acetylcholine from nerve endings. It is the interaction between acetylcholine and the muscle fiber that leads to electrical excitation and muscle contraction. As Katz later wrote, during these experiments, they "encountered an entirely unexpected phenomenon. It turned out that even without any stimulation, the end plate of the muscle fiber is not in a resting state, but, on the contrary, weak potentials of the end plate occur randomly and individually."

In subsequent studies, particularly alongside Jose del Castillo, Katz discovered that "each weak end-plate potential is caused by the simultaneous action of a large number of acetylcholine molecules released in the form of quanta from the efferent nerve endings." The results of these studies were published in 1954, the same year when electron microscopists, including George E. Palade, described the ultrastructure of synapses for the first time. They discovered an astonishing feature – the presynaptic area (i.e., the nerve ending) contained numerous small vesicles. Two years later, Katz and del Castillo proposed that these vesicles contained acetylcholine. When such a vesicle fuses with the synaptic membrane, it releases one quantum of the neurotransmitter, and the mediator molecules diffuse across the synaptic cleft, interact with the muscle cell, and generate a single weak end-plate potential. Thus, as Katz stated later, it was established that "the usual end-plate potential arises as a result of the statistical summation of individual quanta, similar to spontaneously occurring weak potentials."

Katz then posed a crucial question: "How does an impulse that arrives at a nerve fiber... increase the probability of one 'quantal event'?" Over the next 10 years, in collaboration with Ricardo Miledi, Katz attempted to answer this question using techniques similar to those employed by Katz, Hodgkin, and Huxley in the study of action potentials. By that time, it had already been established that the action potential is caused by the movement of sodium and potassium ions across the nerve cell membrane. In 1967, Katz and Miledi demonstrated that the release of the neurotransmitter is associated with calcium ions. Using precise methods to study very weak signals, Katz and his colleagues quantitatively measured the electrical changes produced by the action of a single acetylcholine molecule and showed that each weak end-plate potential corresponds to the effect of several thousand such molecules, precisely the number that should be present in a single synaptic vesicle.

For his discoveries in the field of neurotransmitter research and the mechanisms of their release, excretion, and inactivation, Katz was awarded the Nobel Prize in Physiology or Medicine in 1970. He shared the prize with Ulf von Euler, who discovered that the sympathetic nervous system (a division of the autonomic nervous system responsible for the body's response to stress) uses noradrenaline (norepinephrine) as its neurotransmitter, and Julius Axelrod, who investigated the formation, release from synaptic vesicles, and reuse of noradrenaline. Axelrod also studied the effects of psychotropic drugs on the activity of neurotransmitters and found that, like acetylcholine, noradrenaline is released from synapses in the form of discrete quanta. These and other discoveries demonstrated that Katz's concepts of mediator release mechanisms apply not only to cholinergic synapses (i.e., synapses whose mediator is acetylcholine) but also to all structures in the nervous system.

Achievements and Honors

From 1946, Katz worked at University College London, first as the Deputy Director of Biophysical Research and later, in 1950-1951, as a lecturer in physiology. In 1952, he became a professor of biophysics and the head of the Department of Biophysics.

In 1945, Katz married Margaret Benly, and they had two children together.

In 1969, Katz was granted a knighthood. He received the Bailey Medal of the Royal College of Physicians (1967) and the Copland Medal of the Royal Society (1967). Katz is a member of the Italian National Academy of Sciences, the Royal Danish Academy of Sciences and Letters, the American Academy of Arts and Sciences, and the National Academy of Sciences of the United States. Additionally, he holds honorary titles from the University of Cambridge and the Weizmann Institute of Science in Israel.