[The limitation of the intensity of the stress reaction under open-field test conditions through the adaptation of rats to cold and physical loading].

Male Wistar rats' adaptation to the periodical cold exposure (3 hours daily, 6 times a week within 2 months at the air temperature of 1-2 degrees C) and to the exercise training (swimming 1 hour daily, 6 times a week within 2 months at the water temperature of 32-33 degrees C) was resulted in a limitation of motional and vegetative manifestations of the stress reaction in the "open field" test. Activation of the stress limiting systems in the organism could be one of the main causes of these adaptive effects. There was an elevation of beta-endorphin concentration and that of the ratio "prostacycline/thromboxane" in some tissues of adapted animals.