NIH study examines nicotine as a gateway drug
NIH-funded research in mice shows that nicotine primes the brain to enhance cocaine’s effects. This study identifies a biological mechanism, supporting epidemiological evidence that nicotine is a gateway drug.
Akinso: A ground breaking study in mice has identified a biological mechanism that could help explain how tobacco products could act as gateway drugs. Dr. Nora Volkow an institute director at the NIH explains how this new research follows evidence from studies looking at large numbers of illicit drug users.
Volkow: The epidemiological studies have show that the first drug that most people take is either cigarette smoking or alcohol. And following these they go into other drugs like marijuana and subsequently into drugs like cocaine, or heroin, or methamphetamine.
Akinso: The idea or model of gateway drugs where a person's likelihood of abusing cocaine and perhaps other drugs in the future has been controversial. Dr. Volkow says this study looked at a biological mechanism showing that nicotine had a priming effect in the brains of mice.
Volkow: Investigators looked at different models of the effects of cocaine from the behavior. And so when they pretreated with nicotine the animals conditioned much faster than the animals that had only been given cocaine. And conditioning is a process that we know is indispensible in the process of addiction. The person that's addicted gets conditioned to the drug and that drives wanting to take the drug.
Akinso: To examine whether the results from this study paralleled findings in humans, the researchers reexamined statistics from the 2003 National Epidemiological Study of Alcohol Related Consequences to explore the relationship between onset of nicotine use and degree of cocaine dependence.
Volkow: No one had really studied this in humans. And clearly this is why this study is remarkable. It's identifying basic changes that bring to light the question whether something like this will be happening adolescence that get exposed to nicotine that when they are taking nicotine and then they take cocaine in simultaneous they're going to be much more likely to become addicted to cocaine.
Akinso: Dr. Volkow adds that now that they have a mouse model of actions of nicotine as a gateway drug this will allow them to explore the molecular mechanisms by which alcohol and marijuana might act as gateway drugs. For more information on this finding, visit www.drugabuse.gov. This is Wally Akinso at the NIH, Bethesda, Maryland.