How did mankind discover smoking

Addiction to nicotine through the tongue

04.02.2009

Not only in the brain, but also on the tongue, there are special binding sites for nicotine-nicotine
There are several reasons that the addiction-inducing substance in cigarettes is nicotine:
* Nicotine penetrates the central nervous system (CNS) and is psychoactive.
* The physiological effects of smoking and injected nicotine are identical.
* Nicotine works as a "positive amplifier". Humans (and also animals) add nicotine to themselves in experiments.
* It is easier to get rid of the addictive substance (tobacco abstinence) if nicotine is administered (substituted, i.e. replaced) with medication.
* Smokers tend to adapt their smoking behavior to the different nicotine contents of tobacco products
who are apparently crucial to the development of nicotine addiction. Portuguese and American scientists discovered this in mice and rats, as they report in the journal PNAS.

The nicotine inhaled when smoking reaches the blood via the lungs and then into the brain, where it docks with certain nicotine receptors (nACHRs) and thus causes various messenger substances (such as dopamine) to be released. These trigger a general feeling of wool in the reward system, which can lead to nicotine addiction. So far it has been assumed that nicotine primarily develops its effects in the brain in this way. Now Portuguese and American scientists have discovered nicotine receptors on the tongues of rats and mice, which may play a key role in the development of nicotine addiction. This discovery could open up new possibilities for combating tobacco addiction, write the researchers led by Albino J. Oliveira-Maia from the University of Porto in an online advance publication of the journal PNAS.

Researchers have long suspected that the taste of nicotine, which is mainly described as bitter, also contributes to the development of addiction. So we know that after injuries to the brain regions that are responsible for taste sensations, even with heavy smokers, the craving for nicotine suddenly disappears. On the other hand, people who are very sensitive to bitter substances are non-smokers above average.

Oliveira-Maia and his colleagues have now found in rats and mice that nicotine on the tongue triggers two different reactions in the brain: On the one hand, the taste sensation is transmitted by the taste buds on the tongue via the same signal path that the bitter substances in food take. bitter ”reported to the brain. Independently of this, the nicotine, by docking with the newly discovered, specific nicotine receptors on the tongue, also creates another, separate activity pattern in the brain. After the administration of certain inhibitors, which paralyze these nicotine receptors on the tongue, the animal's brain reaction to nicotine was almost completely prevented in animal experiments. Should it be confirmed that nicotine works in the same way in humans, drugs against nicotine addiction could be applied directly to the tongue, which should increase its effectiveness and reduce undesirable side effects. Previously available active ingredients that target the nicotine receptors in the brain must be taken in tablet form, have a relatively large number of undesirable side effects and only a low long-term success rate of around 20 percent. The researchers hope that the discovery of the nicotine receptors on the tongue may open up a “second front line” for a more effective therapy against smoking with fewer side effects.