Abstract: | Single intraperitoneal injection of substance P in a dose of 125 mcg/kg induced a significant increase of noradrenaline and dopamine level in the hypothalamus and the midbrain of intact rats. Under conditions of immobilization emotional stress, the substance P eliminated the stress induced decrease of hypothalamic noradrenaline and increase of its level in the midbrain; in other words the substance P normalized the noradrenaline level. Modulatory effect of a single injection of the substance P had a long-term character and was synchronized with an earlier found increase of resistability of rats to chronic emotional stress. |