[Molecular and neuronal mechanisms of drug addiction]

Drug addiction is believed to be a chronic and convertible disease resulting in the obtrusive aim of drugs ingestion and the use of them in spite of health risk and life threat. Human behavior is mainly a resultant force of 3 actions of the functional CNS: arousal, reward and cognition. In addition all of them are advanced in the development of drug addiction. For the proper functioning of every complex system it is essential to maintain a proper communication of the elements it is made out of. Therefore the purpose of the paper was to present research results connected with consecutive chain links advanced in the flow of neuronal information. Considering the mechanisms of the formation of addictions recent research draws attention not only to the neuronal role of mezolimbical dopaminergic transmition, but also to the anatomical ground which is the limbic system (localization of the reward system) in the addiction progress. The stimulation of that structure results from catecholamines action, especially dopamine and serotonin, however, endogenic opioid peptides have a modulating effect. The research that is being conducted brings proof that psychostimulant agents may result in the release of adequate neurotransmitters or imitate their influence to the reward system. An important role in the addiction progress play the intracellular transmition mechanisms starting from receptors, through protein G, cyclic AMP and transcription factors. The latter factors may change target genes synthesis resulting in long-term claimed changes. In spite of the discussion about the possibilities of molecular and theoretical examinations, obtained effects transfer for practical applications, there are several non questioned advances like: recognition of cellular adaptation mechanisms, identification of reactions connected with reoccurrence after abstinence period, and possibilities of practical assessment of this knowledge in the dependence pharmacotherapy.