Modern human population intimately recognizes the stress reaction of the organism, which has developed as a response to variety physical and/or psychical stressors. This reaction represents not only a complex of adaptive mechanisms enabling the successful overcoming of the conflicting situation, but in its pathological form it can significantly contribute to the development of serious diseases, from carcinogenic, cardiovascular, gastrointestinal, up to the psychical. New, developing scientific disciplines permit to widen knowledge of the basis of this undesirable side of the stress. Transgenic animals, which either has integrated the gene of interest, or studied gene is not functioning (i.e. knockout animals), permit at least partially to study the physiological importance of the product of this gene in the organism. In our review we described in detail three lines of knockout mice – with the knockout gene for the dopamine-β-hydroxylase, corticoliberin and c-fos – that significantly contribute to the regulation of the stress response.

        Key words: stress, knockout mice, catecholamines