scholarly journals Divergent mechanism regulating fluid intake and metabolism by the brain renin-angiotensin system

2012 ◽  
Vol 302 (3) ◽  
pp. R313-R320 ◽  
Author(s):  
Curt D. Sigmund
Keyword(s):  
Blood Pressure ◽  
Fluid Intake ◽  
Renin Angiotensin System ◽  
Metabolic Effects ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Intracellular Form ◽  
Efferent Pathways ◽  
The Brain ◽  
Pituitary Adrenal Axis

The purpose of this review is two-fold. First, I will highlight recent advances in our understanding of the mechanisms regulating angiotensin II (ANG II) synthesis in the brain, focusing on evidence that renin is expressed in the brain and is expressed in two forms: a secreted form, which may catalyze extracellular ANG I generation from glial or neuronal angiotensinogen (AGT), and an intracellular form, which may generate intracellular ANG in neurons that may act as a neurotransmitter. Second, I will discuss recent studies that advance the concept that the renin-angiotensin system (RAS) in the brain not only is a potent regulator of blood pressure and fluid intake but may also regulate metabolism. The efferent pathways regulating the blood pressure/dipsogenic effects and the metabolic effects of elevated central RAS activity appear different, with the former being dependent upon the hypothalamic-pituitary-adrenal axis, and the latter being dependent upon an interaction between the brain and the systemic (or adipose) RAS.

Central renin-angiotensin system and the pathogenesis of DOCA-salt hypertension in rats

1986 ◽  
Vol 251 (2) ◽  
pp. H261-H268 ◽  
Author(s):  
Y. Itaya ◽  
H. Suzuki ◽  
S. Matsukawa ◽  
K. Kondo ◽  
T. Saruta
Keyword(s):  
Blood Pressure ◽  
Fluid Intake ◽  
Renin Angiotensin System ◽  
Hypertensive Rats ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Plasma Vasopressin ◽  
Baroreceptor Reflexes ◽  
Salt Hypertension ◽  
The Brain

The antihypertensive effect of blockade of the brain renin-angiotensin system (brain RAS) was investigated in DOCA (deoxycorticosterone acetate)-salt hypertensive rats. Continuous intracerebroventricular (ICV) administration of SQ14225 (SQ; 1.25 micrograms X 0.5 microliter-1 X h-1) for 7 days attenuated the increase in blood pressure (99 +/- 5 vs. 116 +/- 4 mmHg on the 7th day) and also reduced the elevation of blood pressure (157 +/- 7 vs. 138 +/- 6 mmHg) in these hypertensive rats. Attenuation of increasing blood pressure in the developing phase following ICV SQ treatment was accompanied by decrease of fluid intake and prevention of elevation of the plasma vasopressin. In the established phase, in addition to reduction of the plasma vasopressin and decrease of fluid intake, restoration of the impaired baroreceptor reflexes was brought about by ICV SQ treatment. These results indicate that the brain RAS strongly influences the regulation of blood pressure in DOCA-salt hypertensive rats and that its mechanism of action is closely related to changes in sodium excretion, vasopressin, and the baroreceptor reflexes.

Role of the Brain Renin-angiotensin System in Blood Pressure Regulation

2007 ◽  
Vol 31 (S1) ◽  
pp. 343-346
Author(s):  
M. V. Varoni ◽  
D. Palomba ◽  
M. P. Demontis ◽  
S. Gianorso ◽  
G. L. Pais ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Renin Angiotensin System ◽  
Blood Pressure Regulation ◽  
Pressure Regulation ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
The Brain

scholarly journals Increased (pro)renin receptor expression in the subfornical organ of hypertensive humans

2018 ◽  
Vol 314 (4) ◽  
pp. H796-H804 ◽  
Author(s):  
Silvana G. Cooper ◽  
Darshan P. Trivedi ◽  
Rieko Yamamoto ◽  
Caleb J. Worker ◽  
Cheng-Yuan Feng ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Animal Models ◽  
Systolic Blood Pressure ◽  
Renin Angiotensin System ◽  
Subfornical Organ ◽  
Antihypertensive Drug Therapy ◽  
Angiotensin System ◽  
Human Hypertension ◽  
Renin Angiotensin ◽  
The Brain

The central nervous system plays an important role in essential hypertension in humans and in animal models of hypertension through modulation of sympathetic activity and Na+ and body fluid homeostasis. Data from animal models of hypertension suggest that the renin-angiotensin system in the subfornical organ (SFO) of the brain is critical for hypertension development. We recently reported that the brain (pro)renin receptor (PRR) is a novel component of the brain renin-angiotensin system and could be a key initiator of the pathogenesis of hypertension. Here, we examined the expression level and cellular distribution of PRR in the SFO of postmortem human brains to assess its association with the pathogenesis of human hypertension. Postmortem SFO tissues were collected from hypertensive and normotensive human subjects. Immunolabeling for the PRR and a retrospective analysis of clinical data were performed. We found that human PRR was prominently expressed in most neurons and microglia, but not in astrocytes, in the SFO. Importantly, PRR levels in the SFO were elevated in hypertensive subjects. Moreover, PRR immunoreactivity was significantly correlated with systolic blood pressure but not body weight, age, or diastolic blood pressure. Interestingly, this correlation was independent of antihypertensive drug therapy. Our data indicate that PRR in the SFO may be a key molecular player in the pathogenesis of human hypertension and, as such, could be an important focus of efforts to understand the neurogenic origin of hypertension. NEW & NOTEWORTHY This study provides evidence that, in the subfornical organ of the human brain, the (pro)renin receptor is expressed in neurons and microglia cells but not in astrocytes. More importantly, (pro)renin receptor immunoreactivity in the subfornical organ is increased in hypertensive humans and is significantly correlated with systolic blood pressure.

Abstract P061: Selective Deletion of Intracellular Renin in the Brain Causes Hypertension and Elevated Sympathetic Nervous System Activity

Hypertension ◽  
2015 ◽  
Vol 66 (suppl_1) ◽  
Author(s):  
Keisuke Shinohara ◽  
Benjamin J Weidemann ◽  
Matthew D Folchert ◽  
Xuebo Liu ◽  
Donald A Morgan ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Metabolic Rate ◽  
Systolic Blood Pressure ◽  
Neural Circuit ◽  
Resting Metabolic Rate ◽  
Renin Angiotensin System ◽  
Power Spectral Analysis ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
The Brain

Renin expression is regulated by two distinct promoter-1st exon combinations that target renin either for secretion (exon 1a for secreted renin) or cytoplasmic retention (exon 1b for intracellular renin, icREN). We developed icREN knockout (KO) mice by selectively deleting exon 1b. icREN KO mice are essentially brain-specific knockouts of icREN because icREN is predominantly expressed in the brain. Notably, systolic blood pressure measured by telemetry was increased in icREN KO mice (130±2 mmHg, n=8 vs 122±2 mmHg in controls, n=7, P<0.01). The low- to high-frequency ratio (LF/HF) derived from power spectral analysis of heart rate variability, a parameter of sympathetic nerve activity (SNA), was increased in icREN KO mice (KO: 1.24±0.21, n=7 vs control: 0.70±0.11, n=7, P<0.05). Body weight (BW) was normal in icREN KO mice compared to controls, but the BW gain and fat accumulation induced by high fat diet (HFD) were attenuated in male icREN KO mice (BW at 16 wks of HFD- KO: 36.8±1.2 g, n=8 vs control: 41.9±1.4 g, n=9; relative fat mass at 14 wks of HFD- KO: 27.7±1.7%, n=8 vs control: 34.4±2.3%, n=9, both P<0.05). The resting metabolic rate measured by respirometry was increased in icREN KO mice (0.156±0.005 kcal/h, n=46, P<0.05) vs controls (0.145±0.003 kcal/h, n=53), whereas food consumption and absorbed calories were not different. We previously reported that the brain renin-angiotensin system facilitates renal SNA (RSNA) response to acute intracerebroventricular (ICV) injection of leptin. Interestingly, the RSNA response to ICV leptin was greater in icREN KO mice (KO: 214±40 % baseline, n=5 vs control: 114±18 % baseline, n=10, P<0.01). AT1a receptor mRNA was upregulated in the paraventricular nucleus of icREN KO mice (P<0.05). Chronic ICV injection of losartan not only abolished the elevated blood pressure in icREN KO mice, but reduced it to below baseline in controls (systolic blood pressure, 111±3 mmHg in KO, n=5; 124±4 mmHg in controls, n=6). These data suggest that icREN deletion increases the activity of brain renin-angiotensin system and elevates blood pressure and metabolic rate through sympathetic activation. We conclude that this novel icREN isoform contributes to cardiovascular and metabolic control possibly as part of an inhibitory neural circuit.

Role of the Brain Iso-Renin-Angiotensin System in Experimental Hypertension in Rats

1981 ◽  
Vol 61 (2) ◽  
pp. 175-180 ◽  
Author(s):  
Hiromichi Suzuki ◽  
Kazuoki Kondo ◽  
Michiko Handa ◽  
Takao Saruta
Keyword(s):  
Blood Pressure ◽  
Plasma Renin Activity ◽  
Renin Angiotensin System ◽  
Plasma Renin ◽  
Renin Activity ◽  
Cerebral Ventricles ◽  
Hypertensive Rats ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
The Brain

1. To examine the possible participation of the brain iso-renin-angiotensin system in the control of blood pressure, as well as in the regulation of plasma renin activity, saralasin and captopril were injected into the cerebral ventricles of three types of experimental hypertensive rats with different plasma renin profiles. 2. Injection of saralasin and captopril into the cerebral ventricles resulted in a significant decrease in blood pressure of two-kidney, one-clip Goldblatt hypertensive rats (11 ± 2 and 9 ± 3 mmHg respectively) and that of spontaneously hypertensive rats (13 ± 2 and 12 ± 2 mmHg respectively), but in deoxycorticosterone (DOC)-salt hypertensive rats injection of these two agents showed a significant increase in blood pressure (13 ± 2 and 12 ± 3 mmHg respectively). 3. The plasma renin activity was markedly decreased after injection of saralasin and captopril into the cerebral ventricles of two-kidney, one-clip Goldblatt hypertensive rats. Conversely, in DOC-salt hypertensive rats, the plasma renin activity was markedly increased after injection of these two agents. In spontaneously hypertensive rats these agents caused no significant change in plasma renin activity. 4. These findings suggest that the brain iso-renin-angiotensin system participates in the central regulation of blood pressure and may be responsible for modulation of the peripheral renin-angiotensin system.

scholarly journals The Brain Renin-Angiotensin System and Mitochondrial Function: Influence on Blood Pressure and Baroreflex in Transgenic Rat Strains

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Manisha Nautiyal ◽  
Amy C. Arnold ◽  
Mark C. Chappell ◽  
Debra I. Diz
Keyword(s):  
Blood Pressure ◽  
Signaling Pathways ◽  
Mitochondrial Function ◽  
Renin Angiotensin System ◽  
Normal Blood ◽  
Ang Ii ◽  
Normal Blood Pressure ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
The Brain

Mitochondrial dysfunction is implicated in many cardiovascular diseases, including hypertension, and may be associated with an overactive renin-angiotensin system (RAS). Angiotensin (Ang) II, a potent vasoconstrictor hormone of the RAS, also impairs baroreflex and mitochondrial function. Most deleterious cardiovascular actions of Ang II are thought to be mediated by NADPH-oxidase- (NOX-) derived reactive oxygen species (ROS) that may also stimulate mitochondrial oxidant release and alter redox-sensitive signaling pathways in the brain. Within the RAS, the actions of Ang II are counterbalanced by Ang-(1–7), a vasodilatory peptide known to mitigate against increased oxidant stress. A balance between Ang II and Ang-(1–7) within the brain dorsal medulla contributes to maintenance of normal blood pressure and proper functioning of the arterial baroreceptor reflex for control of heart rate. We propose that Ang-(1–7) may negatively regulate the redox signaling pathways activated by Ang II to maintain normal blood pressure, baroreflex, and mitochondrial function through attenuating ROS (NOX-generated and/or mitochondrial).

scholarly journals Effects of Phytochemicals on Blood Pressure and Neuroprotection Mediated Via Brain Renin-Angiotensin System

Nutrients ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2761 ◽  
Author(s):  
Hae Rin Kim ◽  
Woo Kyoung Kim ◽  
Ae Wha Ha
Keyword(s):  
Blood Pressure ◽  
Cholinergic System ◽  
Enzyme Inhibitor ◽  
Renin Angiotensin System ◽  
Positive Control ◽  
Control Group ◽  
Dietary Intakes ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
The Brain

Background: The renin-angiotensin system (RAS) in the brain plays a crucial role in maintaining blood pressure as well as neuroprotection. This study compared the effects of curcumin, quercetin, and saponin on blood pressure, the brain RAS, and cholinergic system using perindopril, an angiotensin converting enzyme inhibitor (ACEI), as a positive control. Methods: Five-week-old male mice were stabilized and randomly assigned into a control group (n = 8), three phytochemical-treated groups (curcumin (n = 8), quercetin (n = 8), and saponin (n = 8)), and a positive control group (n = 8). The groups treated with the phytochemical were orally administered daily at a dose of 50 mg/kg body weight of phytochemicals. During the experiments, the weight and dietary intakes were measured regularly. After experiments, the brain tissue was homogenized and centrifuged for an additional assay. The concentrations of ACE, angiotensin II (AngII), and aldosterone levels were measured, and the mRNA expressions of renin and ACE were measured. As biomarkers of neuroprotection, the concentrations of acetylcholine(Ach) as well as the concentration and activity of acetylcholine esterase (AChE) were measured. Results: After 4 weeks of treatment, the perindopril group showed the lowest blood pressure. Among the groups treated with the phytochemicals, treatment with curcumin and saponin significantly reduced blood pressure, although such effect was not as high as that of perindopril. Among phytochemicals, curcumin treatment significantly inhibited the concentration and activity of ACE, concentration of AngII, and mRNA expression of ACE. All phytochemical treatments significantly increased the concentration of ACh. The levels of AChE activity in groups exposed to curcumin or saponin (not quercetin) were significantly inhibited, Conclusion: Curcumin administration in rats reduced blood pressure by blocking the brain RAS components and protected the cholinergic system in brain by inhibiting the activity of AChE.

Abstract 173: Modulation of the Metabolic Effects of Leptin by the Brain Renin-Angiotensin System

Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
Kristin E Claflin ◽  
Aline M Hilzendeger ◽  
Curt D Sigmund ◽  
Justin L Grobe
Keyword(s):  
Physical Activity ◽  
Food Intake ◽  
Metabolic Rate ◽  
Cross Talk ◽  
Renin Angiotensin System ◽  
Suppressive Effect ◽  
Metabolic Effects ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
The Brain

Genetic deletion or delivery of antagonists of the renin-angiotensin system (RAS) directly to the brain abolishes both renal and adipose sympathetic nervous activity (SNA) responses to leptin, suggesting a cross-talk between these central cardiovascular / metabolic control systems. To further explore this mechanism of cross-talk, we examined the sensitivity of metabolic responses in mice with transgenic hyperactivity of the brain RAS (“sRA” mice) to acute leptin treatment. sRA mice, previously shown to exhibit hypertension, polydipsia, and elevated SNA and resting metabolic rate, exhibit brain-specific RAS hyperactivity through neuronal expression of human renin via the synapsin promoter and expression of human angiotensinogen via its own promoter. When housed at standard room temperature (23°C), twice-daily leptin injections (1 mg/kg, i.p., 3 hrs into light phase and 2 hrs preceding dark phase of a 12:12-hr cycle) caused significant and similar reductions in body mass (control -0.76±0.13, n=5 male; sRA -0.65±0.09 g/d, n=5 male, P=0.46) and food intake (-1.43±0.69 vs -1.99±0.27 kcal/d, P=0.63) in littermate control and sRA mice. When housed at thermoneutrality (30°C) in an OxyMax (Columbus Instruments) CLAMS apparatus, leptin injections had minimal effects on total daily food intake in control mice (from 7.4±0.6 at baseline to 8.1±0.5 kcal/d with leptin, n=4 male + 4 female, P=0.29), but reduced food intake in sRA mice (from 8.3±0.7 to 6.0±0.4 kcal/d, n=4 male + 4 female, P=0.003). sRA mice were more sensitive to leptin’s suppressive effect on physical activity (control from 998±148 to 655±90, P=0.10; sRA from 1232±304 to 588±41 counts/d, P=0.005). Unexpectedly, leptin had a suppressive effect upon metabolic rate in sRA mice (control from 16.4±1.3 to 16.8±0.9, P=0.44; sRA from 20.2±1.1 to 17.5±0.9 kcal/kg lean/hr, P<0.001). Together, these data support a cross-talk between the brain RAS and leptin signaling in the control of metabolic function. These data suggest a complex and context-dependent mechanism of interaction between leptin and brain angiotensin, with gross alterations in leptin-induced food, physical activity, and metabolic rate responses when tested in a thermoneutral environment.

Sign in / Sign up

Export Citation Format

Share Document