Event Title
Sexually Dimorphic Effects of Alcohol on Tyrosine Hydroxylase Receptors in the Mesolimbocortical Pathway
Faculty Advisor
Dr. Erin Rhinehart
Start Date
28-4-2020 12:00 AM
End Date
28-4-2020 12:00 AM
Description
Alcohol effects the brain in a sexually dimorphic manner. Men require more alcohol to become intoxicated, and the alcohol has a sedative effect. On the other hand, females are more prone to anxiety-like behaviors, and as a result, alcohol has a greater anxiolytic effect on females than it does on males. The exact mechanism that causes this difference is unknown, but it may have to do with an enzyme known as tyrosine hydroxylase (TH). Tyrosine hydroxylase is the rate-limiting enzyme in dopamine production. When a person consumes alcohol, the ethanol increases dopamine signaling in the mesolimbocortical reward pathway in the brain. Since TH is the rate limiting enzyme for dopamine production, I hypothesized that ethanol increases the amount of TH expression. Since females experience a greater anxiolytic effect in response to alcohol consumption than males, I also hypothesized that ethanol would produce a greater number of TH cell bodies in the ventral tegmental area (VTA) of the mesolimbocortical pathway, as well as increase the density of TH fibers in the nucleus accumbens more in females than in males. To test this hypothesis, naïve adult male and female mice were injected intraperitoneally with either 2g/kg ethanol or saline. Ninety minutes after injection, the mice were anesthetized, transcardially perfused, and their brains were harvested. The brains were then sliced into 35micron thick sections, and were subjected to immunohistochemistry where they were stained with TH and c-fos antibodies before being mounted on slides. The slides were then analyzed, and the number of TH cell bodies in the VTA were recorded for each mouse. In addition, the thickness of the TH fibers in the nucleus accumbens was also recorded for each mouse. The results showed increased TH expression in the ethanol injected mice. In addition, female ethanol injected mice showed greater levels of TH cell bodies in the ventral tegmental area than male ethanol injected mice.
Sexually Dimorphic Effects of Alcohol on Tyrosine Hydroxylase Receptors in the Mesolimbocortical Pathway
Alcohol effects the brain in a sexually dimorphic manner. Men require more alcohol to become intoxicated, and the alcohol has a sedative effect. On the other hand, females are more prone to anxiety-like behaviors, and as a result, alcohol has a greater anxiolytic effect on females than it does on males. The exact mechanism that causes this difference is unknown, but it may have to do with an enzyme known as tyrosine hydroxylase (TH). Tyrosine hydroxylase is the rate-limiting enzyme in dopamine production. When a person consumes alcohol, the ethanol increases dopamine signaling in the mesolimbocortical reward pathway in the brain. Since TH is the rate limiting enzyme for dopamine production, I hypothesized that ethanol increases the amount of TH expression. Since females experience a greater anxiolytic effect in response to alcohol consumption than males, I also hypothesized that ethanol would produce a greater number of TH cell bodies in the ventral tegmental area (VTA) of the mesolimbocortical pathway, as well as increase the density of TH fibers in the nucleus accumbens more in females than in males. To test this hypothesis, naïve adult male and female mice were injected intraperitoneally with either 2g/kg ethanol or saline. Ninety minutes after injection, the mice were anesthetized, transcardially perfused, and their brains were harvested. The brains were then sliced into 35micron thick sections, and were subjected to immunohistochemistry where they were stained with TH and c-fos antibodies before being mounted on slides. The slides were then analyzed, and the number of TH cell bodies in the VTA were recorded for each mouse. In addition, the thickness of the TH fibers in the nucleus accumbens was also recorded for each mouse. The results showed increased TH expression in the ethanol injected mice. In addition, female ethanol injected mice showed greater levels of TH cell bodies in the ventral tegmental area than male ethanol injected mice.