June 09, 2017
New research from Erin Rhinehart, associate professor of biology at Susquehanna University, finds that male and female brains of mice react quite differently to the effects of alcohol.
"Research examining both male and female subjects in the same study in the field of addiction is desperately needed," Rhinehart said. "Several studies show that females respond differently than males to alcohol and many other drugs, but we need more research to discern the exact nature of these differences to better prevent and treat the misuse of alcohol in all populations."
Alcohol stimulates the production of dopamine, the chemical in the brain that produces the sensation of reward and pleasure. The increase in dopamine could happen by boosting the production of tyrosine hydroxylase, the most important enzyme in the chemical process that produces dopamine in the brain.
Rhinehart hypothesized that acute alcohol intoxication would increase the production of tyrosine hydroxylase to stimulate dopamine production and signal the brain's reward pathway in a sex-dependent manner.
To test this hypothesis, Rhinehart injected male and female mice with either alcohol or saline, and later stained the brains to visualize the location and quantity of tyrosine hydroxylase protein in the reward pathway.
Rhinehart found that in female mice, alcohol increased the expression of tyrosine hydroxylase in the midbrain and forebrain areas. Conversely, male mice showed no such reaction.
"The results indicate that the reward pathways in the brain respond differently to acute alcohol intoxication in males and females," Rhinehart said. "This has further implications for understanding the mechanisms that underlie sex differences in susceptibility to alcohol addiction."
Rhinehart said the next step in the research is to examine whether or not this difference is present in adolescent animals and if the difference is maintained across all phases of the female reproductive cycle.
Judy Grisel, professor of psychology at Bucknell University, collaborated on this research.