The Effects of Chronic Adolescent Stress on Physiology as a Function of Time

Open Access
Bacik, Lindsay Caroline
Area of Honors:
Elective Area of Honors - Neurosciences
Bachelor of Science
Document Type:
Thesis Supervisors:
  • Victoria A Braithwaite, Thesis Supervisor
  • Ping Li, Honors Advisor
  • adolescent stress
  • blood composition
  • physiological response to stress
Animals that experience stressful life events undergo psychological, behavioral, and physiological changes. Adolescence is a critical period of development due to increased neuroplasticity in the adolescent brain, and research has focused on the effects of adverse experiences during this time on the adult phenotype. The effects of adolescent stress depend on a range of factors including the duration of the stress exposure and the temporal relationship between stress onset, offset, and physiological response. The present study investigated the differences in blood composition in rodent models at two separate time points as a measure of physiological change. Rats exposed to chronic adolescent stress (e.g. predation simulation, isolation, crowding) were compared to control animals maintained in regular standard housing throughout development. Blood composition collected at a time point allowing for rest after the stress paradigm showed greater neutrophil to lymphocyte ratios (F1,45=19.574, P<0.001), lower lymphocyte count (F1,45=37.268, P<0.001), lower absolute white blood cell count (F1,45=18.010, P<0.001), higher absolute red blood cell count (F1,45=11.150, P=0.002), and lower absolute platelet count (F1,45=53.966, P<0.001). These results showed that with time, the physiological response to stress changes significantly.