ITHACA, N.Y. -- Cornell University researchers, using non-linear laser-microscope technology developed at Cornell, have produced images displaying the neurotransmitter serotonin in live cells in real time, and they have for the first time measured the concentration of serotonin in secretory granules.

The microscope, which uses pulsed lasers for excitation, can record ultraviolet (UV) fluorescence images of live cells without using UV illumination to detect and image cellular activity.

"This technique caught serotonin granules in the act of releasing the substance, without damaging the cell or changing the process and without requiring any external fluorescent marker," said Watt W. Webb, Cornell professor of applied and engineering physics, who led the work. "It is a new way of doing three-dimensional UV microscopy in functioning cells and the best way we know of for doing UV microscopy in thick tissues," Webb said.

The studies were reported in a paper, "Measuring serotonin distribution in live cells with three-photon excitation," published in the journal Science (Jan. 24, 1997) by Webb and Sudipta Maiti, a postdoctoral researcher; Jason B. Shear, former National Science Foundation post doctoral fellow now at the University of Texas at Austin; Rebecca M. Williams, physics graduate student; and Warren R. Zipfel, a research associate, all at Cornell.

Serotonin is a neurotransmitter that is becoming increasingly important as medical science learns of its role in a host of human disorders. It has been implicated in central nervous system disorders such as anxiety, depression, obsessive-compulsive disorder, schizophrenia, stroke, obesity, pain, hypertension, vascular disorders, migraine and even nausea. Serotonin is synthesized in brain neurons and is released upon a nerve impulse, where it interacts with receptors. The antidepressant Prozac (fluoxetine) is thought to treat depression by inhibitin
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Contact: Larry Bernard
lb12@cornell.edu
607-255-3651
Cornell University News Service
23-Jan-1997