Nicotine rats addicted to alcohol?

How smoking increases the susceptibility to alcohol abuse

07/22/2013

Nicotine increase the desire for alcohol - at least in rats. It has long been known that smokers are more likely to abuse alcohol, making tobacco consumption a risk factor for alcohol addiction. Which neural processes require this connection, however, was so far unclear. US scientists from the Department of Neuroscience at Baylor College of Medicine in Houston have now deciphered the underlying effect in rat experiments and their findings in the journal „neuron“ released.

As the research team around William Doyon discovered, smoking inhibits the synaptic transmission that occurs on contact with dopamine neurons, thereby generally affecting the dopamine response. Dopamine acts as a happiness hormone and plays an essential role in the reward system of the brain. Since less dopamine was released in the brains of nicotine rats, they simply increased their intake of alcohol in the experiments. Whether the results apply to humans in a similar way remains uncertain, but this may be an explanation for the increased alcohol abuse among smokers in previous studies.

Smoking as a risk factor for alcohol abuse
„Smoking is a known risk factor for later alcohol abuse, but the underlying neuronal events of this risk have been largely unknown“, write Doyon and colleagues. In experiments with rats, the scientists now examined the effect of early nicotine consumption on the drinking behavior of the animals. They observed that rats under drinking nicotine significantly more often drank from provided drinking containers with alcohol than the animals of the control group. This is mainly caused by the impairment of the dopamine response. The reward system in the brain would be slowed down and the affected animals would seek replacement to stimulate dopamine release. This explains the increased susceptibility to alcohol abuse, but possibly also to other drugs.

Blocking stress hormone receptors in the rats prior to nicotine intake in the experiments has led to the prevention of any previously established link between nicotine and alcohol consumption, the US scientists report. This also applies to the inhibition on dopamine neurons, the decreased dopamine response and the increased alcohol consumption. According to the scientists, the neuronal effect that underlies the increased alcohol abuse among smokers is thus deciphered, although it has not yet been checked to what extent the results can be transferred to humans. If people react in a similar way, experimenting with cigarettes in adolescence could increase susceptibility to alcohol abuse later in life, said study co-author John Dani. He therefore advocated at the same time for an improvement in prevention. If necessary, according to the expert, smoking teens should also participate in appropriate weaning programs. (Fp)

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