Severe food restriction activates the central renin angiotensin system

In this study, we investigated the role of the central RAS in the mean arterial pressure (MAP) and heart rate (HR) dysregulation associated with sFR. A major finding of this study was that central administration of the AT1R antagonist, losartan, reduced the blood pressure after 2  weeks on a sFR diet in Female rats and radioligand binding to the AT1R was selectively increased in the PVN of sFR rats. AbstractWe previously showed that 2  weeks of a severe food restricted (sFR) diet (40% of the caloric intake of the control (CT) diet) up‐regulated the circulating renin angiotensin (Ang) system (RAS) in female Fischer rats, most likely as a result of the fall in plasma volume. In this study, we investigated the role of the central RAS in the mean arterial pressure (MAP) and heart rate (HR) dysregulation associated with sFR. Although sFR reduced basal mean MAP and HR, the magnitude of the pressor response to intracerebroventricular (icv) microinjection of Ang‐[1‐8] was not affected; however, HR was 57 ± 13 bpm lower 2 6 min after Ang‐[1‐8] microinjection in the sFR rats and a similar response was observed after losartan was microinjected. The major catabolic pathway of Ang‐[1‐8] in the hypothalamus was via Ang‐[1‐7]; however, no differences were detected in the rate of Ang‐[1‐8] synthesis or degr adation between CT and sFR animals. While sFR had no effect on the AT1R binding in the subfornical organ (SFO), the organum vasculosum laminae terminalis (OVL...
Source: Physiological Reports - Category: Physiology Authors: Tags: ORIGINAL RESEARCH Source Type: research