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 "m...