Ulf von Euler found the key to the sympathetic nervous system

Chemical messengers known as signal substances or neurotransmitters play a key part in the human nervous system. When a signal reaches the end of a nerve cell, neurotransmitters are released that convey it to the next cell or trigger activity in the organ the nerve regulates.

Ulf von Euler is the scientist who discovered that the signal substance noradrenaline is responsible for the chemical signalling in the sympathetic nervous system, which is a part of the nervous system over which we have no conscious control. It regulates such physiological processes as blood pressure and pulse, and is activated when the body needs to expend energy.

Vital to all mammals

It was for this discovery that Ulf von Euler was awarded the 1970 Nobel Prize in Medicine or Physiology along with Bernhard Katz and Julius Axelrod, for “their discoveries concerning the humoral transmitters in the nerve terminals and the mechanism for their storage, release and inactivation”.

Von Euler conducted his groundbreaking researches on noradrenaline at Karolinska Institutet, where he spent his entire career, becoming professor there in 1937. When he began, chemical signal substances were a known phenomenon, but studies on frogs led scientists to believe that adrenalin was the neurotransmitter of the sympathetic nervous system.

Instead, von Euler was able to demonstrate that it is noradrenaline that serves as the sympathetic signal substance in mammals – as well as in other classes of animal.

Through systematic studies, von Euler showed that noradrenaline was present in almost all organs and tissues, with the exception of the placenta, which has no nerves.

Stored at the ends of nerve fibres

Noradrenaline was found to be secreted in tiny amounts in the urine, which made it relatively easy to measure the activity of the sympathetic nervous system under different conditions. Von Euler and his colleagues were thus able to demonstrate that more noradrenaline is released during hypertensive states, in certain stress situations, and by a certain type of tumour called phaeochromocytoma.

Von Euler and his colleague Åke Hillarp also succeeded in showing that noradrenaline is stored at the end of nerve fibres in tiny particles, or vesicles.

Supportive parents and godfather

Ulf von Euler was born in Stockholm in 1905 and began studying medicine at Karolinska Institutet in 1922. He personally claimed that the scientific atmosphere at home was instrumental in his burgeoning interest in research, which was encouraged but never forced upon him by his parents.

His father, Hans von Euler-Chelpin, received the Nobel Prize in Chemistry in 1929 and his mother Astrid Cleve held a PhD in botany and researched in the field of chemistry. His godfather was Svante Arrenius, the 1903 Nobel laurate in chemistry.

Ulf von Euler took his PhD and became a docent of pharmacology in 1930 under Professor Göran Liljestrand, who secured him a Rockefeller scholarship that same year for postdoc studies under Henry Dale, who went on to be awarded the Nobel Prize in Physiology or Medicine for his discoveries concerning the chemical transmission of nerve impulses.

While working under Dale, von Euler discovered an interesting biologically active substance in intestinal extracts that was given the name Substance P.

Back at Karolinska Institutet, he continued his work on Substance P, whereupon he found another substance that he called prostaglandin, the characterisation of which earned Sune Bergström and Bengt Samuelsson the Nobel Prize in Physiology or Medicine in 1982.

Ulf von Euler died in 1983.