In an important early step toward understanding the chemistry of human thought, Stanford chemists have managed for the first time to read the individual chemical messages that cells exchange.
These messages account for nearly all of the communication that takes place in the brain, but previous efforts to record them one at a time have been thwarted by their extremely small size. More than a billion vesicles -- the microscopic membrane-bound pouches that carry the chemical signals -- could fit into an average-sized drop of water.
"We really are seeing a new era dawning in which people are trying to understand the chemistry of the brain and of the central nervous system, with the possibilities of amazing consequences, from treating mental disease to improving mental powers," says Richard N. Zare, who headed the research effort.
Zare, the Marguerite Blake Wilbur Professor of Chemistry, and his colleagues published the technique that allowed them to read out the contents of individual vesicles in the journal Science earlier this year.
Cells use vesicles to signal each other in a variety of ways. Such messages include mail to the brain that says "ouch!" from a bumped funny bone. Other messages regulate the female reproductive cycle.
By analyzing large numbers of vesicles together, scientists had learned a great deal about the vocabulary of the cell's language. But this method can deduce only average messages. It is as if researchers knew that in 1,000 letters, the word "food" appeared 1,800 times, but they could not discern how many times (if at all) "food" showed up in any one letter.
Zare suspected the average message might not be a good representation of any single vesicle's contents. "Could it be that the real signals are being hidden and confused by looking at only averages?" he wondered. "I thought likely so, and indeed our work shows that to be the case."
The signal from a single vesicle is important because cells send and rec
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Contact: David F. Salisbury
salisbury@stanford.edu
650-725-1944
Stanford University
28-May-1998