Saturday, December 21, 2024
12/21/2024
PROJECT SUMMARY/ABSTRACT Fetal Alcohol Spectrum Disorder (FASD) is a direct result of exposure to alcohol in utero, which produces lifelong behavioral, physical, and intellectual complications. Unfortunately, prenatal alcohol exposure (PAE) increases the likelihood of these individual’s misusing alcohol, and/or developing an alcohol use disorder. Yet, it is unclear what the underlying neurobiological mechanisms are that may contribute to this heightened risk in FASD individuals. This gap in knowledge limits our understanding of neuroadaptations resulting from PAE, therefore limiting our ability to develop targeted treatments for PAE individuals. One system that has been extensively studied for its role in alcohol misuse is the corticotropin releasing factor (CRF) and its receptor type I (CRFR1). CRF and CRFR1 are highly expressed in the central amygdala (CeA) and bed nucleus of the stria terminalis (BNST), also known as the extended amygdala. Our lab has demonstrated that CRFR1 function in the medial nucleus of the CeA (CeM) is blunted in adolescent male animals following PAE on gestational day 12 (G12), a crucial period of development for the amygdala. Interestingly, CRFR1 mediates the actions of acute alcohol in the CeM of adult male rodents. Acute alcohol typically increases GABA release and differently affects the firing rates of neurons expressing CRFR1 (CRFR1+, increased firing) and neurons that do not express CRFR1 (CRFR1-, decreased firing). Moreover, we found that PAE sex-dependently disrupts the actions of acute alcohol in unlabeled CeM neurons of adolescent animals. However, it is unknown how this disruption in function or the alterations in the actions of acute alcohol persists into adulthood, or affects CeM downstream targets, such as the BNST. This led us to our overarching hypothesis that PAE will decrease the function of CeM CRFR1+ → BNST neurons, therefore, reducing inhibitory tone in the BNST of adult male CRFR1-Cre-tdtomato rats. To test this, we will use whole-cell patch-clamp electrophysiology to investigate PAE induced differences in neuronal excitability and neurotransmission in the BNST. Furthermore, we will explore how PAE interacts with acute alcohol to change BNST neurotransmission. Additionally, using a retrograde virus, we will identify how PAE interacts with acute alcohol to alter the firing of CeM CRFR1+ → BNST neurons. Finally, to understand the consequences of activation of CeM CRFR1+ → BNST neurons we will use channelrhodopsin to investigate how PAE interacts with acute alcohol to alter activity of this circuit. Successful completion of this work will expand our understanding of long-term PAE-induced neuroadaptations, and inform future studies designed to develop potential treatments for FASD individuals. Additionally, by completing this work, I will acquire invaluable skills in stereotaxic surgery and viral manipulation which ultimately augments my electrophysiology skills by implementing optogenetics for neural circuitry assessment.
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