Researchers Uncover Why Prenatal Alcohol Exposure Increases the Likelihood of Addiction
10 Jul 2017 --- Neuroscientists are researching how prenatal alcohol exposure alters the reward system in the brain and how this change continues through adulthood. According to the researchers, the key appears to lie with endocannibinoids, cannabis-like chemicals that are produced by the brain itself.
“By understanding the role endocannibinoids play in increasing the brain's susceptibility to addiction, we can start developing drug therapies or other interventions to combat that effect and, perhaps, other negative consequences of prenatal alcohol exposure,” says Roh-Yu Shen, senior research scientist at the University of Buffalo Research Institute on Addictions.
Fetal Alcohol Spectrum Disorders (FASD) cause cognitive and behavioral problems, increased vulnerability to alcohol and other substance use disorders, as well as other mental health issues including Attention Deficit Hyperactivity Disorder (ADHD), depression, anxiety and problems with impulse control.
“After the prenatal brain is exposed to alcohol, the endocannibinoids have a different effect on certain dopamine neurons which are involved in addicted behaviors than when the brain is not exposed to alcohol,” Shen says. “The end result is that the dopamine neurons in the brain become more sensitive to a drug of abuse's effect. So, later in life, a person needs much less drug use to become addicted.”
Specifically, in the ventral tegmental area (VTA) of the brain, endocannibinoids play a significant role in weakening the excitatory synapses onto dopamine neurons. The VTA is the part of the brain implicated in addiction, attention and reward processes. However, in a brain prenatally exposed to alcohol, the effect of the endocannabinoids is reduced due to a decreased function of endocannabinoid receptors, the researchers have found.
As a result, the excitatory synapses lose the ability to be weakened and continue to strengthen, which Shen believes is a critical brain mechanism for increased addiction risk.
