Haemodynamics and the participation of pressor systems in young and adult rats with age-dependent DOCA-salt hypertension.

Increased systemic resistance is the main haemodynamic abnormality in DOCA-salt hypertension which is more pronounced in young than in adult rats. A mild increase of cardiac output also contributes to higher blood pressure in young animals. Arterial compliance is decreased only in young hypertensive rats. The acute blockade of different pressor systems indicates that the role of back-up pressor systems (vasopressin and angiotensin II) is increased in adult DOCA-salt hypertensive animals while the increased activity of adrenergic system and digoxin-like factors contributes to the enhanced hypertensive response of young rats.