The researchers suggest that digestive system cells and odor-detecting cells use the same chloride porthole, or ion transporter -- the former to facilitate secretion of digestive juices, and the latter to communicate information about scents to the brain.

Although scientists have long known that odor-sensing cells require lots of charged chloride atoms, or ions, to relay odor signals to the brain, they did not know how cells keep levels of chloride high inside of the cells. Now Hopkins researchers have shown that these high chloride levels in odor-detecting cells depend on the same transporter, known as NKCC1, used in many other types of cells as well.

"It's not unusual for the body to use the same machinery to solve different problems," notes one of the lead authors, Jonathan Bradley, Ph.D., a postdoctoral fellow in neuroscience. "Chloride is a kind of jack-of-all-trades that cells can hijack to do what they want."

Odor-detecting nerve cells are long and thin, extending from the tissues lining the nose where odors are sensed all the way to the brain. When you smell cookies baking, odor molecules bind to these cells, triggering a series of molecular "gates" on the cell surface to open. The open gates let charged ions, including chloride, move in and out of the cell, creating differences in charge between the inside and outside of the cell. Such differences allow electrical signals to travel to the brain, telling you that home-made cookies are nearby.

Bradley and co-author Johannes Reisert, Ph.D., suspected NKCC1 might be involved in this process precisely because of the transporter's known importance in reg
'"/>

Contact: Joanna Downer or Katherine Unger
jdowner1@jhmi.edu
410-614-5105
Johns Hopkins Medical Institutions
24-Feb-2005