[Age and changes in the levels of biogenic amines in the brains of rats].

No significant change occurs in the total cerebral level of norepinephrine, dopamine, and histamine in rats of 1--36 months age, whereas the serotonin (5-HT) level is increasing. During the maturation period the hypothalamic levels of catecholamines and histamine are increasing. Between 2--36 months of life the hypothalamic norepinephrine level decreases while 5-HT, 5-HIAA, and histamine do not change. Role of the age-related changes of brain biogenic amines in disturbances of neuroendocrine feedback mechanisms is discussed.