[Effect of neonatal 6-hydroxydopamine administration on the catecholaminergic structures of the hypothalamus and on the behavior of rats of various ages].

A neurotoxin 6-hydroxydopamine (6-OHDA) was introduced to 1, 2 and 3 day old male Wistar rats. Falck-Hillarp histochemical fluorescent method was used to analyze hypothalamic and hypophysial structures containing catecholamines. Statistically reliable decrease in catecholamine fluorescence intensity in hypothalamus and hypophysis, accumulation of catecholamines in nerve cells of supraoptic nucleus and in tanycytes of median eminence differed in 25- and 90-days rats. Disturbance of catecholaminergic systems of hypothalamus and hypophysis induced by neonatal introduction of 6-OHDA leads to reliable relaxation of orienting reaction and deep violation of learning that becomes stronger with age.