The 1986 Nobel Prize in physiology or medicine

Rita Levi-Montalcini: the neurologist who challenged fascism

Rita Levi-Montalcini was a researcher in the field of neuroscience, Italian and Jewish in origin, who discovered the nerve growth factor and rightfully earned the 1986 Nobel Prize in Physiology or Medicine, alongside her collaborator Stanley Cohen. She was persecuted by the fascist dictatorship of Benito Mussolini and experienced gender and religious discrimination throughout her entire life. Despite these obstacles, she carried out her activities with diligence and grace, becoming a role model in the field. This paper reviews the life and career of Rita Levi-Montalcini.

The failed attribution of the Nobel Prize for Medicine or Physiology to Viktor Hamburger for the discovery of Nerve Growth Factor

The announcement in October 1986 that the Nobel Prize for Physiology or Medicine was to awarded to Rita Levi Montalcini and Stanley Cohen for the discovery of nerve growth factor (NGF) and epidermal growth factor, respectively, caused many to wonder why Viktor Hamburger in whose laboratory the initial work was done had not been included in the award. This article try to reconstruct the history of the discovery of NGF with the aim to re-establish a correct dynamic of the events.

ADAPTIVE ROLES OF PROGRAMMED CELL DEATH DURING NERVOUS SYSTEM DEVELOPMENT

The programmed cell death (PCD) of developing cells is considered an essential adaptive process that evolved to serve diverse roles. We review the putative adaptive functions of PCD in the animal kingdom with a major focus on PCD in the developing nervous system. Considerable evidence is consistent with the role of PCD in events ranging from neurulation and synaptogenesis to the elimination of adult-generated CNS cells. The remarkable recent progress in our understanding of the genetic regulation of PCD has made it possible to perturb (inhibit) PCD and determine the possible repercussions for nervous system development and function. Although still in their infancy, these studies have so far revealed few striking behavioral or functional phenotypes.

A pact with the embryo: Viktor Hamburger, holistic and mechanistic philosophy in the development of neuroembryology, 1927-1955

Viktor Hamburger was a developmental biologist interested in the ontogenesis of hte vertebrate nervous system. A student of Hans Spemann at Freiburg in the 1920s, Hamburger picked up a holistic view of the embryo that precluded him from treating it in a reductionist way; at the same time, he was committed to a materialist and analytical approach that eschewed any form of vitalism or metaphysics. This paper explores how Hamburger walked this thin line between mechanistic reductionism and metaphysical vitalism in light of his work on the factors influencing growth of neurons into limb buds, and the discovery of nerve growth factor, work carried out with Rita Levi-Montalcini and Stanley Cohen.

Neuronal cell death, nerve growth factor and neurotrophic models: 50 years on

Viktor Hamburger has just died at the age of 100. It is 50 years since he and Rita Levi-Montalcini laid the foundations for the study of naturally occurring cell death and of neurotrophic factors in the nervous system. In a period of less than 10 years, from 1949 to 1958, Hamburger and Levi-Montalcini made the following seminal discoveries: that neuron cell death occurs in dorsal root ganglia, sympathetic ganglia and the cervical column of motoneurons; that the predictions arising from this observation, namely that survival is dependent on the supply of a trophic factor, could be substantiated by studying the effects of a sarcoma on the proliferation of ganglionic processes both in vivo and in vitro; and that the proliferation of these processes could be used as an assay system to isolate the factor. This work provides a short review mostly of the early history of this subject in the context of the Hamburger/Levi-Montalcini paradigm. This acts as an introduction to a consideration of models that have been proposed to account for how the different sources of growth factors provide for the survival of neurons during development. It is suggested that what has been called the 'social-control' model provides the most parsimonious quantitative description of the contribution of trophic factors to neuronal survival, a concept for which we are in debt to Viktor Hamburger and Rita Levi-Montalcini.

Viktor Hamburger and Rita Levi-Montalcini: the path to the discovery of nerve growth factor

The announcement in October 1986 that the Nobel Prize for physiology or medicine was to be awarded to Rita Levi-Montalcini and Stanley Cohen for the discoveries of NGF and EGF, respectively, caused many to wonder why Viktor Hamburger (in whose laboratory the initial work was done) had not been included in the award. Now that the dust has settled, the time seems opportune to reconsider the antecedent studies on the relation of the developing nervous system to the peripheral structures it innervates. The studies undertaken primarily to investigate this issue culminated in the late 1950s in the discovery that certain tissues produce a nerve growth-promoting factor that is essential for the survival and maintenance of spinal (sensory) ganglion cells and sympathetic neurons. In this review, the many contributions that Viktor and Rita made to this problem, both independently and jointly, are reexamined by considering chronologically each of the relevant research publications together with some of the retrospective memoirs they have published in the years since the discovery of NGF was first reported.

The concept of uptake and retrograde transport of neurotrophic molecules during development: history and present status

In the present review honoring Hans Thoenen's contributions to the concept of uptake and retrograde transport of trophic molecules, I have attempted to identify the major historical pathways that had to converge before this concept could be accepted as a fundamental principle in neurobiology. Some of the critical events in this history which are discussed here include: neuron-target interactions, bidirectional trophic signals, axoplasmic transport, receptor-mediated endocytosis, transneuronal trophic signals, the discovery of NGF, the retrograde transport of NGF, and the production of NGF by target tissues. Only when all of these diverse pieces of the puzzle were in place was the concept finally confirmed as being the mechanism that mediates the many phenomena attributed to the regulation and maintenance of neurons by their targets.

Neurotrophins. Keeping track of changing neurotrophic theory

The requirement for neurotrophins in the development of specific neuronal populations is endorsed by transgenic mice lacking neurotrophin receptors, but central nervous regions of the mice are paradoxically unaffected.

Reduction of naturally occurring motoneuron death in vivo by a target-derived neurotrophic factor

Treatment of chick embryos in ovo with crude and partially purified extracts from embryonic hindlimbs (days 8 to 9) during the normal cell death period (days 5 to 10) rescues a significant number of motoneurons from degeneration. The survival activity of partially purified extract was dose-dependent and developmentally regulated. The survival of sensory, sympathetic, parasympathetic, and a population of cholinergic sympathetic preganglionic neurons was unaffected by treatment with hindlimb extract. The massive motoneuron death that occurs after early target (hindlimb) removal was partially ameliorated by daily treatment with the hindlimb extract. These results indicate that a target-derived neurotrophic factor is involved in the regulation of motoneuron survival in vivo.