German-born US physiologist who showed that the passage of a nerve impulse is associated with the release of a chemical at the nerve endings. This chemical, acetylcholine, was later isolated by Dale, and Loewi and Dale shared the 1936 Nobel Prize for Physiology or Medicine.
After obtaining his medical degree at the University of Strasbourg (1896), Loewi studied chemistry, physiology, and pharmacology and was appointed professor of pharmacology at Graz University in 1909 – a position he held until he was expelled by the Nazis in 1938. He emigrated to the USA and in 1940 became a research professor at New York University's College of Medicine.
Loewi's most important findings, in 1920, were concerned with the mechanism of nerve impulse transmission. By electrically stimulating the nerves of a frog's heart, he slowed its rate of contraction. The fluid bathing this heart was then allowed to perfuse a second heart, which was not electrically stimulated. However, the contraction rate of the second heart was also decreased, demonstrating that a chemical released by the first heart into the perfusing fluid was responsible for this action. The chemical was later identified as acetylcholine – the first substance demonstrated to be a chemical neurotransmitter.
Subjects: Contemporary History (Post 1945) — Science and Mathematics.