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Pleasure and pain
Sub-Topics
Pleasure-Seeking Behaviour
Avoiding Pain

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HelpLinked Module: InfoFacts Index NIDALinked Module: National Institute on Drug Abuse NIDALinked Module: InfoFacts Index NIDA
Linked Module: Addictive Qualities of Popular DrugsLinked Module: Drug war factsLien : Neuropharmacology SummaryLien : Info-drogues

Nearly 15% of all men and 30% of all women admit to a craving for chocolate.

Over 300 substances have been identified in chocolate. Some of these, including caffeine and theobromine (another, less powerful stimulant) could actually cause dependency effects. But the amounts of these substances in chocolate are too small to really have any effect.

The same goes for phenylethylamine, a substance related to a family of stimulants called amphetamines. For example, chocolate contains less phenylethylamine than goat cheese.

Anandamide, a neurotransmitter produced naturally by the brain, has also been isolated in chocolate. The neural receptors for anandamide are the same ones to which THC, the main active ingredient in cannabis, binds. The anandamide in chocolate might therefore contribute to the feeling of well-being reported by “chocoholics” (though you would have to eat well over 30 kilos of chocolate to experience effects comparable to one dose of cannabis!).

Be that as it may, many scientists agree that dependency on chocolate could simply be due to its taste, which causes a sensation of intense pleasure that people want to repeat.

Linked Module: chocolat
HOW DRUGS AFFECT NEUROTRANSMITTERS

Dopamine appeared very early in the course of evolution and is involved in many functions that are essential for survival of the organism, such as motricity, attentiveness, motivation, learning, and memorization. But most of all, dopamine is a key element in identifying natural rewards for the organism. These natural stimuli such as food and water cause individuals to engage in approach behaviours. Dopamine is also involved in unconscious memorization of signs associated with these rewards.

It has now been established that all substances that trigger dependencies in human beings increase the release of a neuromediator, dopamine, in a specific area of the brain: the nucleus accumbens. Lien: Neurobiology of addiction and implications for treatment

But not all drugs increase dopamine levels in the brain in the same way.

  • Some substances imitate natural neuromediators and take their place on their receptors. Morphine, for example, binds to the receptors for endorphin (a natural "morphine" produced by the brain), while nicotine binds to the receptors for acetylcholine.
  • Other substances increase the secretion of natural neuromediators. Cocaine, for example, mainly increases the amount of dopamine in the synapses, while ecstasy mainly increases the amount of serotonin.
  • Still other substances block a natural neuromediator. Alcohol, for example, blocks the NMDA receptors.

Click on the names of each of the following drugs to read about how they work and what effects they have.

Alcohol ----- Opiates (heroin, morphine, etc.) ----- Cocaïne ----- Nicotine

Caffeine ----- Amphetamines ----- Cannabis ----- Ecstasy ----- Benzodiazepines

 

Caffeine

The stimulant effect of coffee comes largely from the way it acts on the adenosine receptors in the neural membrane. Adenosine is a central nervous system neuromodulator that has specific receptors. When adenosine binds to its receptors, neural activity slows down, and you feel sleepy. Adenosine thus facilitates sleep and dilates the blood vessels, probably to ensure good oxygenation during sleep.

Caffeine acts as an adenosine-receptor antagonist. This means that it binds to these same receptors, but without reducing neural activity. Fewer receptors are thus available to the natural “braking” action of adenosine, and neural activity therefore speeds up (see animation).

The activation of numerous neural circuits by caffeine also causes the pituitary gland to secrete hormones that in turn cause the adrenal glands to produce more adrenalin. Adrenalin is the “fight or flight” hormone, so it increases your attention level and gives your entire system an extra burst of energy. This is exactly the effect that many coffee drinkers are looking for.

In general, you get some stimulating effect from every cup of coffee you drink, and any tolerance you build up is minimal. On the other hand, caffeine can create a physical dependency. The symptoms of withdrawal from caffeine begin within one or two days after you stop consuming it. They consist mainly of headaches, nausea and sleepiness and affect about one out of every two individuals.

Lastly, like most drugs, caffeine increases the production of dopamine in the brain’s pleasure circuits, thus helping to maintain the dependency on this drug, which is consumed daily by 90% of all adults in the U.S.

General links about caffeine:

Linked Module: How Caffeine WorksLinked Module: The Drug of Choice: Caffeine and the BrainLinked Module: Le mécanisme d'action de la caféine élucidéLien : CaféineLinked Module: Caffeine and Performance
 



For a description of the effects of caffeine and the risks of dependency associated with it, click on the following links:


Linked Module: The Effects of Drugs on the Nervous System (Caffeine)Linked Module: Health Canada: Canada’s Drug Strategy (Caffeine)Lien: The Vaults of Erowid: Caffeine

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