Commemorative: Oleh Hornykiewicz, world’s leading neuroscientist (1926-2020)

Ukraine-born Oleh Hornykiewicz passed away on 26 May 2020 aged 93. His greatest achievement and contribution to humanity was “opening a new approach in the control of Parkinson’s disease by L-Dopa”, as stated by the Wolf Foundation Prize Committee in Medicine in their decision to award the Prize in Medicine for 1979 to Roger W. Sperry, Oleh Hornykiewicz and Arvid Carlsson.

Oleh Hornykiewicz was born in 1926 in Sykhiw (a district of Lviv), then in Poland and now – in Ukraine.  His family fled in 1940 when the Soviet Army invaded. In 1951, he received his M.D. degree from the University of Vienna and joined the faculty of his alma mater the same year and has worked there ever since. He obtained a scholarship from the British Council with the intention to work with the German-born physician, biochemist and Nobel Laureate Sir Hans Krebs in Oxford. As Krebs had no appropriate project for him, he was recommended to Hugh (Hermann) Blaschko, another German émigré. Under his auspices, Hornykiewicz worked on the role of dopamine in peripheral tissues of guinea pigs.

Back to Vienna, Hornykiewicz decided to investigate dopamine in human brains. Together with his assistant Herbert Ehringer, he examined post-mortem brain material, 3–20 h after death, from 20 controls, 2 patients with Huntington’s chorea, 6 with other extrapyramidal diseases and 6 with Parkinson’s disease with a rather insensitive colorimetric method. In the basal ganglia of controls as well as in the Huntington cases, they found high concentrations of dopamine, whereas it was diminished by a factor of approximately 10 only in the Parkinsonian patients. In 2007, Hornykiewcz stated: ‘For the first time, a specific chemical abnormality was found in a specific brain region in specific brain disorder…’. Later, with a more sensitive spectrofluorometric method, Hornykiewcz demonstrated dopamine depletion in the pars compacta of substantia nigra and was determined to replace the missing dopamine in Parkinson’s disease patients by L-dopa. A year later, he initiated the first clinical trials of medication to treat this disorder. His development of L-dopa for the treatment of Parkinson’s disease revolutionized treatment and remains the cornerstone of therapy today. Thousands of patients worldwide have benefitted from his research and discoveries.

The fact that Hornykiewicz never received a Nobel Prize for his work was a cause of some outrage among neuroscientists: more than 250 neuroscientists signed an open letter to the award committee in 2000. His observations stimulated the studies of Arvid Carlsson, Paul Greengard and Eric Kandel (all Nobel recipients in 2000) that mapped the signaling regulation pathways of the brain’s most important functions.

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