Early-life stress has an impact on brain development and adult behavior. However, little is known about what stress does to brain cells. Doctoral student Nyasha Gondora is studying the cellular-level impacts of stress.
Over a prolonged period of time, stress can affect the brain’s communication network by changing brain cells, or neurons. But not all stress is bad.
The effects of stress can be positive in the short-term – like adrenaline release to help escape a dangerous situation," explains Gondora, a Waterloo School of Pharmacy doctoral student in the Faculty of Science. "But if stress is chronic it has negative effects on multiple organ systems.
Prolonged stress can change both how a neuron fires and its overall shape. These changes in firing and shape can impact the neuron’s function.
Receptors, the parts of the brain that receive and transmit the signals communicated between neurons, may also change as a result. For example, if chronic stress causes neurons to fire over and over again, receptors may become "desensitized" and stop transmitting the message.
Gondora, a member of Dr. Michael Beazely's lab, is interested in these stress-induced neuronal changes. In particular, she is studying how early-life chronic stress affects the expression of receptors in two brain regions: the hippocampus and the pre-frontal cortex. Additionally, she is also exploring whether or not males or females respond differently to stress.
What does early life stress do to brain cells?
To do this, she explored the impact of chronic early-life social isolation by comparing rats that were exposed to social isolation against those that were not.
Surprisingly, Gondora found the results differed by gender in the two brain regions. In the prefrontal cortex, stressed male rats had significantly more receptor expression than stressed females and the control groups.
Overactivation of that specific prefrontal cortex receptor is often associated with pathological pathways in various conditions such as schizophrenia and strokes. These outcomes suggest that males may be more susceptible to stress than females.
By contrast, stressed female rats had a significantly greater expression of a receptor in the hippocampus compared to males and the control groups.
When this receptor is expressed in the hippocampus it is neuroprotective in its signalling.
This finding suggests that females could be subject to some neuroprotective mechanism more so than males.”
Next steps in stress research
Gondora’s preliminary results illustrate that a variety of factors, perhaps even gender, impact how we respond to stress. She intends to repeat her experiment with more cohorts to explore if her results remain consistent, saying that more research is required before confident assertions can be made.
Ultimately, she hopes her research can “allow us to understand the big picture, see the specific ways that stress impacts us, and enable us to better tackle those consequences.”
Gondora won the 2016 Association of Faculties of Pharmacy of Canada (AFPC) Research and Development Poster Award for her work (her presentation is pictured left). The internal poster competition award at Waterloo Pharmacy is supported by AFPC. She then went on to win the National Award at AFPC’s annual conference in June.
Nyasha is co-supervised by Dr. John Mielke from the Faculty of Applied Health Sciences and obtained the data for the presented study in collaboration with his research group.
This research project was supported by the National Science and Engineering Research Council and the Canadian Institutes of Health Research-Drug Safety and Effectiveness Cross Disciplinary Training Program.