Current research projects include human and animal investigations into individual differences in the biobehavioral effects of stress.
Our human studies focus on the examination of sex differences in neuroendocrine and immunologic responses to stress in humans. In particular, we are interested in the role of posterior pituitary hormones, such as oxytocin, and cytokines (IL–1B and IL–6) in moderating biobehavioral responses to stress in men and women. This research, funded by the National Science Foundation, is based on a new stress theory — a biobehavioral response we label "tend-and-befriend" (Taylor, Klein, et al., 2000), which is a biobehavioral pattern of stress responses that includes the creation and maintenance of social networks and nurturant activities designed to protect the individual and their offspring. Other human studies in our lab include investigating the stress-mediating effects of nicotine and caffeine on neuroendocrine, immune, and cognitive responses in men and women. Portions of this research are funded by the Office of Naval Research and are being conducted in collaboration with colleagues in the Penn State University School of Information Sciences and Technology. In collaboration with the departments of Human Development and Family Studies, Industrial/Organizational Psychology, and the School of Hospitality Management, we have been able to investigate the effects of day–to–day stressors via telephone daily diary interviews and saliva collection on the diurnal rhythm of cortisol, DHEA–S, and melatonin in the employees and families of the hotel industry. This collaboration was part of a phase I project that included six sites across the U.S. funded by NICHD, NIOSH, NIA and OBSSR. In phase II, which the lab is gearing up for, we will use our daily diary interviews and hormone assessment to evaluate the effectiveness of a workplace intervention on the health of employees and their children.
Our animal research is designed to investigate biological stress mechanisms that are difficult to study in humans. Specifically, we design animal models that are believed to parallel the human stress condition. We currently are investigating the influence of adolescent nicotine exposure (a potent biological stressor) on drug abuse in adulthood and have developed an adolescent mouse model of nicotine consumption to evaluate the phenomenon that 90% of adult smokers start smoking before the age of 18 (Klein et al. 2004). Our laboratory also was the first to develop an animal model of the epidemiologic report that kids who smoke are more likely to use drugs as they get older (Klein, 2001). We now are examining gene responses to nicotine exposure in reward-relevant brain regions to determine underlying mechanisms for the development of drug addiction. In addition, we are also assessing how specific cytochrome P450 inhibitors affect the metabolism and elimination of nicotine in adolescent mouse models. Along with stressors, we are also attempting to examine immunological biomarkers to understand how stressors influence the adaptive immune system.