Sex Differences in Tyrosine Hydroxylase Expression Within the Norepinephrine System of the A1 Anatomical Region in Mice (2023)
Undergraduates: Aakanksha Gundu, Ali Fahim, Anjali Chandrasekhar, Eymania Alston
Faculty Advisor: Sabrina Robertson
Department: Psychology & Neuroscience
Norepinephrine-producing neurons have several projections throughout the central nervous system and play a vital role in physiological and behavioral processes such as attention, mood, stress response, memory, and homeostasis. Many neurological diseases are a result of dysregulation of the norepinephrine system. Therefore, understanding sex differences in norepinephrine neuronal expression may lead to insight into how neurological disorders affect men and women uniquely. In this project, we investigated tyrosine hydroxylase expression in non-orchidectomized male mice and non-ovariectomized female mice. Tyrosine hydroxylase is an essential enzyme used in the conversion of dopamine to norepinephrine in NE neurons. Using a NE neuron-specific Flpo allele, we applied a gene targeting approach to visualize eGFP (a biomarker of dopamine-B-hydroxylase) expression in the A1 anatomical brain region. Following gene targeting, brain samples underwent incubation with a dual-primary antibody solution containing chicken anti-GFP and rabbit anti-tyrosine hydroxylase followed by a secondary antibody solution containing goat anti-chicken Alexa 488 and goat anti-rabbit Alexa 568. Through this technique, NE neuronal expression was characterized by eGFP fluorescence, and TH was visualized through mCherry fluorescence. The results revealed that in the A1 anatomical region, GFP expression co-localizes with TH and female mice had significantly higher A1 TH expression than their male counterparts. Throughout the history of neuroscience, research was conducted on male participants with the belief that the results would equally be applicable to females, which caused research to neglect hormonal and structural neurological differences. Our research aims to bridge this gap by exploring treatment disparities in endocrinology, gynecology, and neurology.
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