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Nobel Prize in Physiology or Medicine · 1970
Sir Bernard Katz
A stateless Jewish refugee from Nazi Germany who found that nerves pass their messages in tiny packets of chemical.
The Nobel citation: “for their discoveries concerning the humoral transmitters in the nerve terminals and the mechanism for their storage, release and inactivation”
- Born
- March 26, 1911, Leipzig, Germany
- Died
- April 20, 2003, London, United Kingdom
- Shared with
- Ulf von Euler, Julius Axelrod
- Affiliation at the time
- University College, United Kingdom
Medicine prize
1970
Shared with 2 other laureates.
Age that year
59years
Born in 1911.
Sources cited
16
Fact-checked September 24, 2026.
- Stateless from age six until 30, he reached England in 1935 with a League of Nations refugee pass, a temporary visa and £4.
- In 1933 his research won a Leipzig prize entered under a pen name. Once he was known to be the Jewish winner, the prize money was publicly withheld and paid privately.
- In 1938 a German-language physiology review refused to print his article without an 'Aryan' co-author. He withdrew it, and Oxford University Press published it as a book.
- He and a colleague noticed tiny random electrical blips in resting muscle. Instead of dismissing them as noise, he showed each was one packet of nerve chemical.
- During the Second World War the former refugee commanded an Australian air force radar station on Goodenough Island, off New Guinea.
The breakthrough
Nerves release their chemical messenger in fixed-size packets
Nerves pass messages to muscles across a tiny gap. By the 1930s, Henry Dale, Otto Loewi and others had shown that the nerve ending releases a chemical, acetylcholine, which the muscle detects. Katz asked how that release actually works. Around 1950, with Paul Fatt, he pushed extremely fine electrodes into single frog muscle fibres and saw tiny, random electrical blips even when the nerve was resting. It would have been easy to dismiss them as recording errors. Katz showed that each blip was the muscle's response to one packet of acetylcholine holding at least a thousand molecules. In 1954, with José del Castillo, he showed that the large signal produced by a nerve impulse is built from whole numbers of these same packets. Normally a few hundred are released within a thousandth of a second. Think of a vending machine that only sells sealed cans. You can get one can or two hundred, but never half a can. Katz linked the packets to tiny bubbles, called synaptic vesicles, that electron microscopes had recently revealed inside nerve endings. With Ricardo Miledi he gathered strong evidence that calcium entering the nerve ending triggers the release. Earlier, with Alan Hodgkin, he had helped show that the peak of the nerve impulse itself is caused by sodium rushing into the fibre. The same packet rules were later found at synapses throughout the nervous system, including the brain.[3],[5],[7],[8],[9],[10],[11],[15]
“I had a rebirth at the age of 24 when I arrived at the port in Harwich, England, one afternoon in February 1935.”
What it meant for humanity
Katz changed how scientists understand the way nerve cells talk to muscles and to each other. Before him, it was known that a chemical carries the message, but not how the chemical is released. He showed that it leaves the nerve ending in countable packets, that calcium triggers their release, and that the packets come from vesicles. Reviewers writing in 2007 called his core conclusions about packets and calcium indisputable facts and noted that the work appears in every modern neuroscience and physiology textbook.
This framework helps doctors make sense of diseases of the nerve-muscle junction. In Lambert-Eaton myasthenic syndrome, which is often linked to small cell lung cancer, the immune system attacks calcium channels in nerve endings, so fewer packets of acetylcholine are released and muscles weaken. The drug amifampridine (3,4-diaminopyridine) works by lengthening the electrical signal in the nerve ending, so more calcium gets in and more packets are released. It improved strength in four placebo-controlled trials and was described in 2011 as the treatment of choice. Katz himself pointed to this line of clinical research in his Nobel lecture.
His methods also opened doors for others. His analysis of the electrical 'noise' caused by acetylcholine gave the first, indirect look at how single ion channels behave. Bert Sakmann, who had worked in Katz's department, and Erwin Neher later recorded single channels directly and shared a Nobel Prize in 1991. His explanation of partial agonists, drugs that switch a receptor on only part of the way, was influential in pharmacology. His department at University College London drew young researchers from around the world.
The main benefit is understanding rather than a single cure: later researchers built on his rules to explain how drugs, toxins and diseases act on synapses.
- A 2007 review in The Journal of Physiology said his findings on packet release and its control by calcium are taught in every modern neuroscience and physiology textbook.[3],[8]
- Lambert-Eaton myasthenic syndrome is explained as too few acetylcholine packets being released, and its main drug, amifampridine, works by increasing packet release.[3],[12]
- His 'noise analysis' with Ricardo Miledi gave the first indirect measurements of single ion channels, a step toward the patch-clamp recordings of Neher and Sakmann (Nobel Prize 1991).[6],[7],[15]
- With Alan Hodgkin he helped show in 1949 that the peak ('overshoot') of the nerve impulse is caused by sodium ions flowing into the nerve fibre.[7],[11],[15]
- His department at University College London became a magnet for postdoctoral researchers from all over the world and shaped a generation of synapse and ion-channel scientists.[7]
Impact in numbers
Katz's gift was a rulebook, not a product. He showed how a nerve ending releases its chemical messenger: in fixed packets, triggered by calcium entering the terminal, most likely from vesicles. Those rules are taught to every student of neuroscience and are the starting point for work on how drugs, toxins and diseases act at synapses. Doctors use this framework to explain Lambert-Eaton myasthenic syndrome, and its main drug works by increasing the number of packets released. His measurements of electrical 'noise' pointed the way to recording single ion channels. We make no quantified claim. No study separates Katz's share of any medical outcome from the many researchers who built on his work, and the conditions where his framework applies most directly are rare. Any number of lives saved or dollars earned would be invented, not measured.
Fundamental scienceHealth
No number is given here on purpose. Some contributions cannot be counted honestly, and we would rather describe them than invent a figure.
The double edge
We found no documented harm arising from Katz's discoveries. His work, like much physiology of his era, relied on isolated frog nerves and muscles, and he killed very large numbers of frogs. He wrote that he never overcame his dislike of the killing and was unsure it could be morally justified, though he did not think it worse than killing animals for food.
- Minor
Animal experiments
Katz's discoveries came from nerve-muscle preparations taken from frogs. In his autobiography he said he had killed a very large number of them, never lost his dislike of doing so, and could not be sure of a valid moral justification, while arguing it was no worse than killing animals for food.[6]
Against the odds
Katz grew up in Leipzig, home to about 12,000 Jews in 1933 and one of Germany's largest Jewish communities. His parents were Jewish immigrants from the Russian Empire, and after 1917 the family was stateless. Prejudice started early. At nine he was refused a place at a secondary school despite good exam marks, officially because he was a foreigner; he later heard the headmaster did not want 'a Russian Jew' topping the intake. Around 1922 a classmate told other boys of his father's plan to gas Leipzig's Jews in an underground hall. At university, most of his fellow students stopped hiding their Nazi sympathies. After Hitler took power in 1933, a new law excluded Jews from the civil service and Jewish academics were dismissed. The prize money for Katz's award-winning student research was publicly withheld because he was not 'Aryan'. He finished his medical degree in 1934 and in February 1935 left for England with a stateless person's pass and £4. Even abroad, Nazi racial policy reached him: in 1938 a German-language review refused his article without an 'Aryan' co-author. He got his parents out of Germany in March 1939. Those who stayed faced worse: on Kristallnacht in November 1938, 553 Jewish men in Leipzig were arrested, and deportations from the city began in 1942. Katz stayed stateless until 1941, then served as a radar officer in the war against Japan.
1917
Other
After the Russian revolutions of 1917 his family lost their nationality. Katz remained stateless, without a proper passport, until he became a British subject in 1941 at the age of 30.[6],[7]
1920
Discrimination
At nine he passed the entrance exam for the Schiller Real-Gymnasium in Leipzig but was refused as a foreigner. He later learned the headmaster did not want the intake topped by a Russian Jewish boy.[6],[7]
1922
Discrimination
A classmate from a violently antisemitic family spread rumours about him and told other boys of his father's plan to kill Leipzig's Jews with poison gas in an underground hall. Katz later called it an early sign of ideas later put into practice.[6],[7]
1933
Discrimination
His research won the Leipzig medical faculty's Siegfried Garten Prize, entered under a pen name. Once the winner was known to be 'non-Aryan', the prize money was publicly withheld; his professor, Martin Gildemeister, later paid it to him privately.[6],[7]
1933
Persecution
After Hitler took power, an April 1933 law excluded Jews from the civil service, and Jewish academics were dismissed. Katz, then a medical student in Leipzig (about 12,000 Jews in 1933), weighed abandoning his studies to emigrate.[6],[13],[14]
1935
Exile
Seeing no future for himself in Nazi Germany, he left in February 1935 with a League of Nations stateless person's pass, a temporary British visa and £4, and was questioned at length on arrival at Harwich.[2],[6],[7]
1938
Persecution
His parents were still in Germany during Kristallnacht in November 1938, when 553 Jewish men were arrested in Leipzig and the city's 1855 Moorish-style synagogue was destroyed. He got them out of Germany in March 1939.[6],[16]
1938
Discrimination
The editor of the review series Ergebnisse der Physiologie refused to publish his commissioned article without an 'Aryan' co-author. Katz withdrew it; Oxford University Press published it as a book in 1939.[6]
1942
War
After naturalization he joined the Royal Australian Air Force and served as a radar officer in the South West Pacific, commanding 305 Radar Station on Goodenough Island from October 1942 to March 1943.[2],[6],[7]
Jewish background
Katz was born in Leipzig to Max Katz, a fur merchant from Mogilev in the Russian Empire, and Eugenie Rabinowitz. He wrote that all his known relatives were Ashkenazi Jews from Eastern Europe, and that he was raised in a liberal, non-Orthodox way. As a teenager he became an active Zionist: he joined a Zionist student group, ran appeals for the Jewish National Fund, met Chaim Weizmann in 1934 and at one point planned to settle in Palestine. He married Marguerite Penly, who was not Jewish, in 1945.[2],[6],[7]
Key dates
March 26, 1911
Born in Leipzig, Germany, the only son of Max Katz, a fur merchant from the Russian Empire, and Eugenie Rabinowitz.[1],[2],[7]
1920
Refused a place at the Schiller Real-Gymnasium as a foreigner; attends the König Albert Gymnasium in Leipzig from 1921 to 1929.[2],[6],[7]
1933
Wins the Siegfried Garten Prize for physiological research, but the prize money is publicly withheld because he is Jewish; his professor pays it privately.[2],[6],[7]
November 1934
Obtains his medical degree (M.D.) from the University of Leipzig, where he had studied since 1929.[2],[6]
February 1935
Leaves Nazi Germany for London and joins A.V. Hill's laboratory at University College London.[2],[6]
1939
After a London PhD (1938), moves to Sydney to work with John Eccles and Stephen Kuffler, bringing his parents, whom he had got out of Germany.[2],[6]
1941
Becomes a British subject, ending 24 years of statelessness; joins the Royal Australian Air Force as a radar officer in 1942.[2],[6],[7]
1949
With Alan Hodgkin, shows that sodium ions flowing into the fibre cause the peak of the nerve impulse.[7],[11]
1952
With Paul Fatt, reports spontaneous 'miniature' end-plate potentials; becomes Professor of Biophysics at UCL and a Fellow of the Royal Society.[2],[8],[9]
1954
With José del Castillo, shows the nerve signal is built from whole-number 'quanta' of acetylcholine.[8],[10]
1969
Knighted.[2]
1970
Shares the Nobel Prize in Physiology or Medicine with Ulf von Euler and Julius Axelrod.[1],[4]
1990
Receives an honorary doctorate from the University of Leipzig, the university he had left 55 years earlier.[7]
April 20, 2003
Sources
- 1.Sir Bernard Katz - Facts · NobelPrize.org (Nobel Prize Outreach)
- 2.Sir Bernard Katz - Biographical (from Nobel Lectures, Physiology or Medicine 1963-1970) · NobelPrize.org (Nobel Foundation), 1970
- 3.On the Quantal Mechanism of Neural Transmitter Release (Nobel Lecture, 12 December 1970) · NobelPrize.org, 1970
- 4.Press release: The Nobel Prize in Physiology or Medicine 1970 · NobelPrize.org (Karolinska Institutet), 1970
- 5.Speed read: Passing the message on (Nobel Prize in Physiology or Medicine 1970), by Sophie Petit-Zeman · NobelPrize.org, 2009
- 6.Sir Bernard Katz (autobiographical chapter), in The History of Neuroscience in Autobiography, Volume 1, ed. Larry R. Squire, pp. 348-381 · Society for Neuroscience
- 7.Bernard Katz 1911-2003 (obituary by David Colquhoun), Physiology News 52 · The Physiological Society, 2003
- 8.Bernard Katz, quantal transmitter release and the foundations of presynaptic physiology (Augustine GJ, Kasai H, J Physiol 578:623-625) · The Journal of Physiology (via PubMed Central), 2007
- 9.Spontaneous subthreshold activity at motor nerve endings (Fatt P, Katz B, J Physiol 117:109-128) · The Journal of Physiology (via PubMed Central), 1952
- 10.Quantal components of the end-plate potential (del Castillo J, Katz B, J Physiol 124:560-573) · The Journal of Physiology (via PubMed Central), 1954
- 11.The effect of sodium ions on the electrical activity of the giant axon of the squid (Hodgkin AL, Katz B, J Physiol 108:37-77) · The Journal of Physiology (via PubMed Central), 1949
- 12.Update on treatment options for Lambert-Eaton myasthenic syndrome: focus on use of amifampridine (Lindquist S, Stangel M, Neuropsychiatr Dis Treat 7:341-349) · Neuropsychiatric Disease and Treatment (via PubMed Central), 2011
- 13.Germany: Jewish Population in 1933 (Holocaust Encyclopedia) · United States Holocaust Memorial Museum
- 14.Law for the Restoration of the Professional Civil Service (Holocaust Encyclopedia) · United States Holocaust Memorial Museum
- 15.Sir Bernard Katz 1911-2003 (obituary), Australian Neuroscience Society (archived copy) · Australian Neuroscience Society (via Internet Archive), 2003
- 16.Leipzig: Jewish heritage and history · Cultural Guide to Jewish Europe (jguideeurope.org)
Fact-checked on September 24, 2026 by a separate AI fact-checking pass that re-opened the sources, with 4 corrections made. How we check
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