Nicotine Acts as “Gateway” Drug to Cocaine, Study in Mice Finds

Nicotine appears to be a “gateway” drug that primes the brain to be susceptible to cocaine, according to a new study in mice.

The researchers say if further studies show the findings apply to humans, a decrease in smoking rates in young people would be expected to lead to a decrease in cocaine addiction, the Los Angeles Times reports.

The study found mice exposed to nicotine in drinking water for at least seven days showed an increased response to cocaine. The researchers also looked at data on cocaine use among a group of high school students, and found 81 percent of those who started using cocaine did so in a month when they were smoking tobacco.

The findings appear in the journal Science Translational Medicine.

Previous studies have shown that most illegal drug users report using tobacco products or alcohol before they started illicit drug use, according to a news release by the National Institute on Drug Abuse, which funded the study. Until now, studies have not shown a biological mechanism through which exposure to nicotine increases vulnerability to illegal drug use, the release notes.

“Now that we have a mouse model of the actions of nicotine as a gateway drug this will allow us to explore the molecular mechanisms by which alcohol and marijuana might act as gateway drugs,” lead author Eric Kandel, MD, of Columbia University Medical Center, said in the release. “In particular, we would be interested in knowing if there is a single, common mechanism for all gateway drugs or if each drug utilizes a distinct mechanism.”