Dr. Joaquín Luco Valenzuela

This out-standing national scientist is for many, who prepared the professionalization of the scientific activity in Chile. Described, by who knew him, as an exceptional man, of joyful spirit, who delivered, specially, his passion for science, his love for Neurobiology and his desire to live intensely.

Joaquín Luco Valenzuela was borned on July 18, 1913, studies medicine at University of Chile and receives his degree of medical surgeon in 1936. He continues with his post-doctorate studies in Harvard University, with Walter Cannon and Arturo Rosenbluth, between the years 1937 y1938.

At the end of the 30's decade, he devotes himself full-time to the research in Physiology, to the teaching and to the university work in general. In 1939, with only 26 years, he is named as Director of the Catholic University's Medicine School, position that he develops for 10 years and that he combines with his labour as teacher in Physiology and Pharmacology, in the same university.

In 1950, the enormous relevancy of his researches, allows him to inaugurate his Neurophysiology chair. Five years later the Catholic Pontifical University of Chile awarded him as Honorary Honoris Causa. For his valuable work in the scientific world and his contribution to Neuroscience, he received in 1975 the Science National Prize.

Three were the most important fields in Luco's studies:

The Neuron's Trophic Function: These studies go back to the 50's decade and refer to those functions responsible for the structural, biochemical and functional integrity of innervated organs. In these experiments it was possible to establish that the appearance of the degenerative changes present in the muscle after cutting the nerve, were correlated directly by the quantity of nervous tissue that remained to the muscle. Therefore, when the nerve was cut far from its contact spot with the muscle, the degenerative changes appeared late, while a section of the nerve near to the muscle unleashed very rapid changes. This set of studies it's known as the "Paradigm of the long and short nerve", and it was published by Luco and Carlos Eyzaguirre in the Journal of Neurophysiology in 1955. This study raised a possible mechanism through which the nerve controlled the muscle and implied the presence of a trophic factor, which was produced in the motor neurons and could be delivered to the muscle through the axonal flow. Today we know that the trophic factors exist and several of them are known, as the agrin, which controls the acetylcholine recipients, and certainly the nervous growth factor, NGF, which was worth the Nobel Prize to Rita Levi-Montalcini.

Crossed Reinnervations and the Molecular Induction: This is another research subject that Luco pursued for years, how a motor nerve modifies the molecular expression in a smooth muscle, with which it never had previous contact. This scientist's work postulates that the correct function of the nervous system depends on the development and the maintenance of specific connections between nervous cells and their innervated organs. In 1957, Christian Vera, Juan Vial and Luco publish in the Journal of Neurophysiology, that the cat's nictitating membrane, formed by smooth and innervated musculature by motor cholinergic fibbers, and so the smooth reinnervated muscles were capable of contracting and lost the hyper sensibility to adrenalin. Ten years later, together with Ana Maria Lennon they showed that the acetyl cholinesterase increased to values not observed before in a smooth muscle; finally in 1979, Inestrosa, Méndez and Luco published in Nature magazine, that the motor nerve was capable of inducing in the reinnervated smooth muscle, a synaptic form of the acetyl cholinesterase, called 16 S or asymmetric form, which is only found in the neuromuscular union of the skeletal muscles. This way, took shape the concept that Luco imagined many years earlier, the motor nerve possesses inductive properties that defines the gene expression of relevant macromolecules to the neural function in the innervation element.

Learning and Memory in Invertebrates: These studies were developed in the 60's decade, using the Blatta orientalis cockroach. In them, Luco confirmed that to condition the cockroach it's required the integrity of the Nervous System. Nevertheless, once acquired the suitable reaction, only a nervous ganglion is enough to evoke the response of the past. In simple words, this means that for the process of information acquisition, its necessary a major neuronal substratum than for the retention of the learned process and also for the past evocation. Luis Aranda y Luco's works published in Nature in 1964 and 1966, helped to establish that the finest bases of the memory reside in specific places of the neuronal connectivity. Here it's important to mention Davidovich, Chen and Alejandro Donoso, who also took part of this enterprise

These relatively simple studies, performed in an invertebrate's Nervous System, allowed Luco to generate the minimum conceptual frame necessary in order that other researchers could center in the genetic bases of conduct as the learning and memory molecular bases. Eric Kandel, the area's Nobel Prize winner, said that Luco not only facilitated the way, but if Luco had realized his career in The United States, he had won the Nobel Prize.

Another of his big contributions to the development and professionalization of the science in Chile was his dedication to the task of multiplying the opportunities for the activity of the scientists of the country, participating with Niemeyer, Cori, Croxatto, Luxoro, Vargas and others, in the creation of the Research Science and Technology National Commission, CONICYT.

Numerous scientists were this teacher's students of. Among them stand-out the knowledge neurobiologist, Francisco Varela and the biophysicists Francisco Bezanilla and Julio Vergara. In addition, Luco Valenzuela opened his house's doors organizing meetings in those gathered to discuss novice and consecrated scientists. In these gatherings Humberto Maturana, Fernando Orrego Salas and Patricio Sanchez took part, among others.

A Harvard ex-teacher, John Nicholls, referring to the impact that the courses of the International Brain Research Organization, IBRO, could have in the students exposed to Neuroscience, said: "The best examples that I know of a transcendence figure that has been exposed to Neuroscience and has been capable of changing the area of an entire continent have been Joaquín Luco's cases in Chile and T.P. Feng in China".

In 1981 and after an impressive career, he retires and dies on July 19, at 89 years-old, leaving an immeasurable legacy for the national and international scientific world.

Luco taught that the important is to do new things, to be creative, to open roads, and that not only is required passion in the daily occupation, but also its necessary the patience, the continuity and the confidence of knowing that when the questions are transcendent, the answers, even though they take long, they arrive and the dreams finally make real.

When he turned 78 years-old, was asked about the research lines in which he had developed his biggest contributions, in particular ¿With which of them he had felt more satisfaction? His answer was: "Well, it happens that I had different ages. There are different emotions. Sometimes one gets moved because it took a lot to do it, other times the thought falls from heaven...Being one itself the scale, it can't be compared".

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