Oral administration of losartan influences aminopeptidase activity in the frontal cortex

Abstract

Although there is a brain renin–angiotensin system, its mechanisms of control are not fully understood. We studied the effect of oral administration of the AT 1 receptor antagonist losartan on brain aminopeptidase (AP) activity, which plays a major role in neuropeptide metabolism. Six AP activities, related and non-related with the angiotensin (Ang) metabolism, were measured in their soluble and membrane-bound forms in the frontal cortex of control animals and rats treated with losartan, chronically administered via the drinking water. The results demonstrate that soluble pGluAP and membrane-bound AspAP and GluAP increased significantly in losartan-treated animals, indicating that the blockade of the AT 1 receptor stimulates the activity of AP involved in the Ang metabolism. Moreover, the blockade of the AT 1 receptor induces changes not only in the brain angiotensin metabolism, but probably also in that of other neuropeptides.