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A brain leptin-renin angiotensin system interaction in the regulation of sympathetic nerve activity
Journal article   Open access   Peer reviewed

A brain leptin-renin angiotensin system interaction in the regulation of sympathetic nerve activity

Aline M Hilzendeger, Donald A Morgan, Leonard Brooks, David Dellsperger, Xuebo Liu, Justin L Grobe, Kamal Rahmouni, Curt D Sigmund and Allyn L Mark
American journal of physiology. Heart and circulatory physiology, Vol.303(2), pp.H197-H206
07/15/2012
DOI: 10.1152/ajpheart.00974.2011
PMCID: PMC3404702
PMID: 22610169
url
https://doi.org/10.1152/ajpheart.00974.2011View
Published (Version of record) Open Access

Abstract

The sympathetic nervous system, leptin, and renin-angiotensin system (RAS) have been implicated in obesity-associated hypertension. There is increasing evidence for the presence of both leptin and angiotensin II receptors in several key brain cardiovascular and metabolic control regions. We tested the hypothesis that the brain RAS plays a facilitatory role in the sympathetic nerve responses to leptin. In rats, intracerebroventricular (ICV) administration of losartan (5 μg) selectively inhibited increases in renal and brown adipose tissue (BAT) sympathetic nerve activity (SNA) produced by leptin (10 μg ICV) but did not reduce the SNA responses to corticotrophin-releasing factor (CRF) or the melanocortin receptor agonist MTII. In mice with deletion of angiotensin II type-1a receptors (AT 1a R −/− ), increases in renal and BAT SNA induced by leptin (2 μg ICV) were impaired whereas SNA responses to MTII were preserved. Decreases in food intake and body weight with ICV leptin did not differ in AT 1a R −/− vs. AT 1a R +/+ mice. ICV leptin in rats increased AT 1a R and angiotensin-converting enzyme (ACE) mRNA in the subfornical organ and AT 1a R mRNA in the arcuate nucleus, suggesting leptin-induced upregulation of the brain RAS in specific brain regions. To evaluate the role of de novo production of brain angiotensin II in SNA responses to leptin, we treated rats with captopril (12.5 μg ICV). Captopril attenuated leptin effects on renal and BAT SNA. In conclusion, these studies provide evidence that the brain RAS selectively facilitates renal and BAT sympathetic nerve responses to leptin while sparing effects on food intake.
kidney Cardiovascular Neurohormonal Regulation brown adipose tissue angiotensin II type-1a receptor deletion captopril losartan angiotensin-converting enzyme

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