Finally, we analyzed the expression of the brain-derived neurotrophic factor (BDNF)- tropomyosin receptor kinase B receptor (Trk-B) system as BDNF regulates ethanol intake by activation of downstream gene products like pDYN [26] and is known to have a role in alcohol dependence vulnerability [25,27,28,29]. Here, BDNF is linked to alcohol dependence.