A component in saliva has opened a window into a person's psychological health, reflecting resiliency in the face of stress, say researchers at the University of Oregon and Arizona State University.
That component is salivary nerve growth factor, a neurotrophic protein abbreviated as sNGF. It typically is linked to the survival, development or function of neurons, but now may be a marker of stress response.
"We usually focus on the depleting aspects of the stress response, but now we are recognizing that there may be a regenerative or replenishing aspect," said Heidemarie Laurent, a professor of psychology at the UO and lead author on a study published Sept. 27 in the journal Psychosomatic Medicine. "We are seeing that sNGF responds to stress, and that this response relates to both short-term and more lasting measures of psychological health — in other words, sNGF seems to underlie resilience rather than risk."
For the study, Laurent collected five saliva samples from 40 young adults (17 male, 23 female) twice before and three times following a stressful conflict-resolution task. The participants were drawn from a larger study of romantic couples. Samples also were taken from a 20-member control group at the same time intervals but in the absence of the conflict scenario. Samples were analyzed for sNGF and two other stress-linked indicators. Changes in sNGF were significant in the experimental group in response to the conflict.
The saliva was analyzed at ASU's newly opened Institute for Interdisciplinary Salivary Bioscience Research, which is headed by study co-author Douglas Granger, a pioneer in the field of salivary bioscience. "The use of oral fluid as a research and diagnostic specimen has tremendous potential,” said Granger, a professor of psychology. "Have you ever wondered why adversity affects some people more negatively than others? Well, it is possible that sNGF is an important piece of that puzzle."
Nerve growth factor was discovered in the 1950s by Italian neurologist Rita Levi-Montalcini and Stanley Cohen in collaborative research done at Washington University in St. Louis; they later shared the Nobel Prize in Physiology and Medicine in 1986. Much has been uncovered about its role in the brain and nervous system, but few scientists considered how NGF levels in people's saliva might be related to the behavioral and biological components of the body's stress response.
Laurent is a new faculty member in the UO's Department of Psychology and an adjunct faculty member at the ASU institute. At the time of the study, Laurent was at the University of Wyoming. Sean Laurent, an adjunct professor of psychology at the UO, also was a co-author.
The group's new paper is the first of a series related to sNGF and its benefits in the study of social relationships and behavior. "One of the things that makes sNGF so different is that it is related to positive attributes," Granger said. "So rather than being a risk marker, sNGF has the potential to index resilience. This research offers important insights that could revolutionize the way adaptive stress responses are understood and measured — not simply as activation in any one system, but as a pattern of activation across multiple, linked systems."
- story and photo by Jim Barlow, UO Office of Strategic Communications