[Brain catecholamines and the hypothalamo-hypophyseal-adrenocortical system in hereditary arterial hypertension]

Central catecholaminergic mechanisms regulating hypothalamic-pituitary-adrenocortical system (HPAS) and arterial blood pressure (ABP) are closely related. In adult rats with inherited stress-induced arterial hypertension (ISIAH rats), response of the HPAS to emotional stress is diminished. At the same time, the level and metabolic rate of noradrenaline (NA) in many brain regions taking part in the HPAS and ABP control are decreased, and the number of alpha 1-adrenoceptors in the medulla is elevated. Age-dependent changes and interstrain differences in basal and stress-induced plasma corticosterone levels and brain noradrenaline were studied at the age from 2 up to 18 weeks in ISIAH rats and normotensive Wistar rats. It was found that the 4th week of life in the ISIAH rats is a critical period in the development of inherited hypertension. At this time, fast forming of the hypertension is accompanied by an increase in adrenocortical stress responsivity and a fall in the medulla and hypothalamic NA contents. A short-term augmentation of the brain NA synthesis on the 4th week by L-DOPA and carbidopa treatment in the ISIAH rats was followed by a normalization of the arterial pressure and pituitary-adrenocortical function in adult animals accompanied by restoration of hypothalamic and medulla NA levels and medulla alpha 1-adrenoceptor number.