Sensitization is a phenomenon which might contribute to addiction and psychic dependence. Contrary to tolerance, sensitization is characterized by increased behavioural response after repeated administration of a drug. This article reviews findings on experimental treatment of sensitization to opioids measured mostly by changes of locomotion in mice and rats and considers possible neurobiological mechanisms of sensitization to opioids. A number of drugs affecting opioid, dopaminergic, glutamatergic, gabaergic and serotoninergic systems have been tested in experimental therapy and prevention of sensitization to opioids. However, none of the substances tested until now has proved to be perfect in this respect. On the other hand, there are substances that seem to be promising for treatment or prevention of sensitization to opioids, but have not been tested as yet.

        Key words: morphine, opioids, sensitization, experimental therapy, GABA, serotonine, NMDA, AMPA, dopamine