Cell channel finders garner medical Nobel.

Two German cell physiologists won the 1991 Nobel Prize in Physiology or Medicine this week for proving that tiny pores dot the outer membranes of cells and allow the cells to take up and excrete charged atoms.

Erwin Neher of the Max Planck Institute for Biophysical Chemistry in Gottingen and Bert Sakmann of the Max Planck Institute for Medical Research in Heidelberg, who will share the $1 million prize, showed how such channels regulate a cell's internal levels of sodium, potassium, calcium or chloride ions. Channel defects underlie disorders such as diabetes, epilepsy, cystic fibrosis and some forms of heart disease.

Neher and Sakmann proved the existence of ion channels in the late 1970s after developing a technique called "patch clamping." This procedure, now widely used in studies of cell communication, allowed them to isolate and study the activity of a single channel. Ten years ago, they reported monitoring the opening and closing of 15 types of channels among more than 20 different cell types (SN: 11/7/81, p.295).

The researchers "conclusively established with their technique that ion channels do exist, and how they function," states the Nobel Assembly of the Karolinska Institute in Stockholm. "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."

Together, Neher and Sakmann found that specific channels only accept ions of the correct size, and that the channels contain charged regions used to filter out ions bearing the wrong charge. The Nobel worked out the process used by cells to secrete substances such as hormones and neutrotransmitters. By measuring electrical changes at the cells' surfaces, he determined that secretory cells spew out their products after inner-membrane vesicles bubble to the surface and fuse with the cells' outer membranes.