Ph.D. student Mary Gemmel
An estimated 8 percent of women will use antidepressants during pregnancy, according to recent studies. In the past several years, researchers have been interested in the effect of antidepressants on offspring neuronal development.
Mary Gemmel, a fifth-year Ph.D. student in Biological Sciences, argues that the direct effect of medication only tells one part of the story. She is working to piece apart the effects of maternal stress and selective serotonin reuptake inhibitors (SSRI) exposure in offspring. Gemmel was recently awarded first prize (tied with Ph.D. student Catherine Early) for the best graduate student poster at Neuroscience Research Day.
SSRIs are a class of antidepressant that are most commonly prescribed to women suffering from perinatal depression. These medications elevate levels of serotonin available between neurons and have been shown to help alleviate symptoms of depression and anxiety.
Gemmel said although previous research has suggested that maternal use of SSRIs may be linked to developmental disorders such as autism and attention deficit hyperactivity disorder in children, Clinical work is often challenged by its ability to control for levels of maternal stress and depression.
“There were many articles that came out around 2015 to 2016, that were all relating SSRIs to autism … But there’s so many different factors,” Gemmel said. “My research is aimed looking at two of those factors: SSRI exposure as well as maternal depression. (This helps us) weigh the benefits and risks of treatments.”
Gemmel presented her poster at the first annual Neuroscience Research Day.
Working with her faculty advisor Jodi Pawluski (now a professor at the University of Rennes in France), and co-advisors Soichi Tanda and Sonsoles De Lacalle, Gemmel quantified changes in neurobiology and behavior of pre-adolescent and adult rats that were exposed to maternal SSRI treatment.
Gemmel analyzed animal social behavior during her experiments. She measured biochemical markers important for neuronal function such as serotonin, dopamine (a neurotransmitter with a closely related biochemical pathway), and metabolites of serotonin. She also measured markers of synaptic plasticity, such as synaptophysin and postsynaptic density protein 95.
Interestingly, the study revealed clear sex-dependent differences in the physiology and behavior of SSRI-exposed offspring. Female rats displayed heightened social behavior, as well as elevated presynaptic density and neurogenesis in the hippocampus. Conversely, male rats displayed abnormal aggression. Gemmel said she is still investigating the underlying cause of this differentiation, as well as what these results might mean for clinical applications in humans.
Representative photomicrographs of doublecortin (DCX)-ir cells in the granule cell layer (GCL). DCX is used by researchers as a marker for neurogenesis.
“(The SSRI exposure) has to be affecting females and males differently somehow,” Gemmel said. “We know that serotonin plays a role in sexual differentiation, so this might be (due to) brain-region specific changes on behavior …. Looking at both behavior and brain-related changes helps us better understand some of these underlying differences between males and females.”
For more information about Neuroscience Research Day and the Neuroscience Program, visit https://www.ohio.edu/cas/biosci/research/neuro-research.cfm.
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