The renin-angiotensin system and noradrenaline release in the hypothalamus and medulla oblongata

Abstract

The effect of angiotensin II (AII) and 48 h bilateral nephrectomy on the 3H-norepinephrine (3H-NE) and 3H-NE metabolites release in vitro was studied in slices of male Wistar rat hypothalamus and medulla oblongata.The total 3H outflow of radioactivity was higher in AII exposed tissues than in nephrectomized ones of both organs.The 3H-NE and 3H-NE metabolites remanent radioactivity in the tissues increased in both the soluble cytoplasmatic fractions and the granular vesicle ones, in the two organs from the nephrectomized rats.The ratio between granular and cytoplasmatic NE and granular and cytoplasmatic radioactive metabolites was not noticeably altered in any of the groups.The release of 3H-NE caused by AII and the opposite effect by nephrectomy, agree with the inverse relationship demonstrated between endogenous NE content in the central nervous system and AII plasmatic levels.AII might act on presynaptic NE receptors of the cellular membrane.The relationship between the renin-AII system and the central nervous system catecholamines could be involved in the control of development and maintenance of the renal arterial hypertension.