Rita Levi-Montalcini flew mice to Rio in her handbag

Person: Rita Levi-Montalcini
Lived: 1909–2012
Field: Neurobiology
From: Italian

The story

Rita Levi-Montalcini arrived at Washington University in St. Louis in 1947 to work with the embryologist Viktor Hamburger. He introduced her to work by Elmer Bueker, who had found that a mouse tumour grafted onto chick embryos became invaded by nerves. Repeating the experiment, she saw nerve fibres sprout around the tumour like a halo and spread into tissues they would never normally reach, even entering the embryo's veins. Because the nerves grew in the veins but not in the arteries leading back to the tumour, she reasoned that the tumour was releasing a substance into the blood that made nerves grow.

To prove it, she needed a simpler and faster test than working with whole embryos. A friend from her student days in Turin, Hertha Meyer, ran a large tissue-culture laboratory in Rio de Janeiro. So, as Washington University later recounted, Levi-Montalcini put two live mice carrying the tumour into her handbag and flew to Brazil in 1952. There, working with Meyer at the institute of biophysics of the University of Brazil, she placed fragments of tumour in glass dishes next to embryonic nerve tissue and watched dense haloes of nerve fibres grow toward them.

Their 1954 publication became the first definitive evidence for the substance that was named nerve growth factor (NGF). While she was in Rio, the biochemist Stanley Cohen was recruited to the St. Louis group to help identify it. Cohen found, to his surprise, that snake venom made extracts more active, because the venom was itself rich in NGF. That clue led him to mouse salivary glands, an even richer source, and by 1959 the two had produced an antiserum against purified NGF that wiped out parts of the nervous system in newborn mice.

In 1986 Levi-Montalcini and Cohen shared the Nobel Prize in Physiology or Medicine for their discoveries of growth factors. The story of the mice in the handbag became one of the best-loved anecdotes in the history of neuroscience, a sign of her boldness and practicality. Hundreds of growth factors are now known, affecting almost every part of biology, and the simple dish test she ran in Rio was the step that turned a puzzling observation into one of them.

Why it matters

The Rio experiment turned a puzzling observation into a measurable test, opening the way to the discovery of growth factors and decades of research in neuroscience and cancer.

About Rita Levi-Montalcini

Italian-Jewish neuroscientist who, barred by Mussolini’s race laws, ran a secret lab in her bedroom, and later discovered nerve growth factor, winning the 1986 Nobel Prize.

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Rita Levi-Montalcini

1909–2012 · Neurobiology

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