BUFFALO, N.Y. -- University at Buffalo biophysicists have identified a component of venom from a very large, very hairy Chilean tarantula that blocks the action of ion channels that are responsible for cellular mechanical responses -- the cell's ability to feel.

These channels or pores in the cell membrane -- called stretch-activated channels because stretching the membrane causes them to open and close -- have been implicated in functions as diverse as the senses of touch and hearing, muscle contraction and coordination, and blood pressure and volume regulation.

This is the first report of a substance -- in this case a small protein -- that specifically blocks stretch-activated channels. Until now, it has been difficult to associate these channels with particular functions because there were no chemical compounds known specifically to block them.

Results of the research appear in the current issue of the Journal of General Physiology. Scientists from the University of Virginia, Michigan State University and NPS Pharmaceuticals collaborated with UB researchers on the study.

The newly identified peptide toxin could have several clinical applications related to cell mechanics, said Frederick Sachs, Ph.D., UB professor of physiology and biophysics, and senior researcher on the project.

"For example, cells swell during congestive heart failure. The peptide interferes with that process. We also know from earlier work that stretching the heart can initiate fibrillation. If we can block the stretch-activated channels, we may be able to block fibrillation, a major cause of death following heart attacks."

Addressing another area, Sachs said tumor invasion of brain tissue produces a deformation of the surrounding normal cells, causing them to release growth factors that may facilitate or accelerate tumor growth. Stretch-activated channels may be the signal for normal cells to release growth factors.

"This peptide blocks those cha
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Contact: Lois Baker
ljbaker@buffalo.edu
716-645-5000, x 1417
University at Buffalo
15-May-2000