Nobel Prize

Erwin Neher

Born: 20 March 1944, Landsberg, Germany

Affiliation at the time of the award: Max-Planck-Institut für Biophysikalische Chemie, Goettingen, Federal Republic of Germany

Prize motivation: "for their discoveries concerning the function of single ion channels in cells"

Nobel Lecture Ion Channels for Communication Between and Within Cells

Bert Sakmann

Born: 12 June 1942, Stuttgart, Germany

Affiliation at the time of the award: Max-Planck-Institut für medizinische Forschung, Heidelberg, Federal Republic of Germany

Prize motivation: "for their discoveries concerning the function of single ion channels in cells"

Nobel Lecture Elementary Steps in Synaptic Transmission Revealed by Currents through Single Ion Channels

Press Release: From the Nobel Assembly at the Karolinska Institute

7 October 1991

The Nobel Prize Assembly at the Karolinska Institute has today decided to award the Nobel Prize in Physiology of Medicine for 1991 to Erwin Neher and Bert Sakmann for their discoveries concerning "the function of single ion channels in cells".

Summary

Each living cell is surrounded by a membrane which separates the world within the cell from it's exterior. In this membrane there are channels, through which the cell communicates with it's surroundings. These channels consist of single molecules or complexes of molecules, and have the ability to allow passage of charged atoms, that is ions. The regulation of ion channels influences the life of the cell and it's functions under normal and pathological conditions. THe Nobel Prize in Physiology of Medicine for 1991 is awarded for the discoveries of the function of ion channels. The two German cell physologisists Erwin Neher and Bert Sakmann have together developed a technique that allows the registration of the incredibly small electrical current (amounting to a picoampere-10-12A) that passes through a single ion channel. The technique is unique in that it records how a single channel molecule alters it's shape and in that way controls the flow of current within a time frame of a few millionths of a second.

Neher and Sakmann conclusively established withe their technique that ion channels do exist and how they function. They have demonstrated what happens during the opening or closure of an ion channel with a diameter corresponding to that of a single sodium or chloride ion. Several ion channels are regulated by a receptor localized to one part of the channel molecule which upon activation alters it's shape. Neher and Sakmann have shown which parts of the molecule that constitute the 'sensor' and the interior wall of the channel. They also showed how the channel regulates the passage of positively or negatively charged ions. This new knowledge and this new analytical tool has during the past ten years revolutionized modern biology, facilitated research and contributed to the understanding of the cellular mechanisms underlying several diseases, including diabetes and cystic fibrosis.

Neher and Sakmann also used the electrode pipette to inject different agents into the cell and they could thereby investigate the different steps in the secretory process within the cell it self. In this way a number of cellular secretory mechanisms have been clarified such as the role of cyclic AMP (see Nobel Prize to Sutnerland 1971) or calcium ions. For instance, we now have a better understanding of how the hormone levels in the blood are maintained at a certain level.

Also the basal mechanisms underlying the secretion of insulin have been identified. The level of blood glucose controls the level of glucose within the insulin-forming cell, which in turn regulates the level of energy rich substances, ATP. ATP acts directly ona particualr type of ion channel which controls the electric membrane potential of the cell. The change of membrane potential then indirectly influences other ion channels, which permit calcium ions to pass into the cell. The calcium ions subequently trigger the insulin secretion. In diabetes the insulin secretion is out of order. Certain drugs commonly used to stimulate insulin secretion in a diabetes act direct on the ATP controlled ion channels.

In summary, Neher and Sakmann's contributions have meant a revolution for the field of cell biology, for the understanding of different disease mechanisms and opened a way to develop new and more specific drugs.

For additional information: Nobel Prize in Physiology & Medicine 1991