Tuesday, September 22, 2009

Nobel Laureate: Ivan Pavlov


The Nobel Prize in Physiology or Medicine 1904

"in recognition of his work on the physiology of digestion, through which knowledge on vital aspects of the subject has been transformed and enlarged"

Ivan Petrovich Pavlov (1849 - 1936) (Иван Петрович Павлов) won the Noble Prize in 1904 for his contribution to understanding the physiology and biochemistry of digestion. Part of his contribution was the discovery that some of the digestion enzymes needed to be activated before they could work in the stomach [Monday's Molecule #133].

Pavlov is famous for his work with dogs. Most people know of his studies on conditioned reflexes where he was able to show that the mere anticipation of food caused dogs to salivate. He is famous as one of the founders of modern psychology but the Nobel Prize was for a different study where he examined the stomach secretions of dogs by redirecting secretory ducts to the exterior where the secretions could be collected and analyzed. Pavlov was actually more of a biochemist than a psychologist!

Pavlov had a large, well-equipped lab with many workers. In that sense he was much more of a professional scientist than many of the other biological scientists of the late nineteenth century. Pasteur was another example. Many others, like Charles Darwin, worked alone and didn't seek out students.

The knowledge gained from his studies on digestion had no practical application in medicine. They simply advanced our understanding of how our bodies work. In presenting the Nobel Prize the presenter, Count K.A.H. Mörner, took pains to make this point clear and to pronounce it a good thing. Science for the sake of knowledge.

One gets the impression that the audience at the award ceremonies needed to hear that.

Here's part of the Presentation Speech that describes Pavlov's contribution.

Nobel Laureates
In the early days opinions on the course of digestion were speculations as to what was termed as «cooking» or «grinding» in the stomach etc. So long as the digestive processes could not be observed or investigated directly in the stomach no real knowledge could be obtained. An accident turned physiological research in this field in a direction which has later become very important. In the 1820's a young man sustained a gunshot wound in the stomach and developed a gastric fistula which to some extent permitted the gastric processes to be studied. Observations were carried out on this man by the American physician W. Beaumont. This accidental path of investigation, allowing actual observation of processes taking place in the digestive tract, was later followed by many workers using animals. Technique is an important factor in such experiments and has been perfected in a masterly way by Pavlov, whose animals remain in good health, without any injury to the function of their digestive tract, permitting observation and systematic investigation over an almost unlimited period.

These methods for the study of the physiology of digestion established by Pavlov have been taken up by various physiological institutions, but above all much important work was performed in his own laboratory. From this has followed a far-reaching transformation of our knowledge in this field which has also been enriched by new fundamental facts.

The following may be mentioned as an illustration.

The digestive canal can be influenced in various ways by the nervous system. When we remember that the nervous system can induce not only the secretory processes as well as the movements of various parts of the system, but also can bring such processes to a standstill, that it controls the blood supply to these organs and that sensory nerves arise from them, we can get an idea of the complexity one encounters. The complications become still greater when it is realised that we must take into account not only nervous pathways having their origin in the brain or the spinal cord, but also the sympathetic nervous system, and that we have further to pay attention to the interdependence between the different parts of the digestive system through the nerves, so that variations in the behaviour of one may affect that in other organs.

It is in the nature of things that cognition of the scope and character of the functional interdependence of the nervous system and the digestive organs is of great importance to the knowledge of the physiology of these organs. It is also clear that one can only hope that answers to these complicated questions will advance step by step by much research. In this respect Pavlov has acquired very great merit. He has revealed new points of view and has fruitfully stimulated the solution of these problems, and through his methods has made it possible to reach conclusive analysis of them.

The images of the Nobel Prize medals are registered trademarks of the Nobel Foundation (© The Nobel Foundation). They are used here, with permission, for educational purposes only.

[Photo Credit: Pasteur [Hulton Archive/Getty Images]

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