Researchers found that smoking can increase the vulnerability of a person to alcohol addiction, though the mechanism behind this is yet to be determined.

Previous studies have confirmed that smoking has a higher chance of leading to alcohol abuse. In a new study conducted on rats, researchers from the Baylor College of Medicine, found that even a single exposure to nicotine by smoking can drastically increase a person's vulnerability to alcohol addiction. Nicotine temporarily changes how the brain's reward system responds to alcohol and uses stress hormones to reinforce the properties of alcohol.

"Our findings indicate the mechanisms by which nicotine influences the neural systems associated with alcohol abuse, providing a foundation for conceptualizing strategies aimed at diminishing the link between smoking and later alcohol abuse," said senior author Dr. John Dani of the Baylor College of Medicine in a press release.

In the course of the study, researchers observed that rats exposed to nicotine drank more alcohol than rats that were not exposed to nicotine. The nicotine dampened the brain's reward system by initially activating stress hormone receptors and then increasing  inhibitory signaling in the brain. By dampening the brain's reward system, rats exposed to nicotine were able to drink more alcohol than other rats.

"Young people typically experiment with nicotine from tobacco in their teens, and that exposure possibly contributes to a greater vulnerability to alcohol abuse later in life. Therefore, greater vigilance is called for to prevent the initial exposure to nicotine and to follow those at risk," says Dr. Dani. "In addition, our work suggests that stress hormones are candidate targets for prevention or treatment therapies."

The study was published in the Cell Press journal Neuron.