bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 652: Regulation of Cardiac MicroRNA miR-208a by Angiotensin II and the Beta-Adrenergic Receptor Blocker Nebivolol
Authors: Gul Rukhsana , DeMarco Vincent G , Rajyaguru Niral , Sowers James R , Speth Robert C , Pulakat Lakshmi
Published: March 2022

The microRNA miR-208a is a pathologic myo-miR required for hemodynamic pressure overload induced cardiac fibrosis. It is unclear how cardio-deleterious hormones and cardioprotective drugs regulate expression of miR-208a. We
hypothesized
that the pro-inflammatory hormone angiotensin II (Ang II) and anti-inflammatory drugs rapamycin (Rap: inhibitor of the nutrient sensor kinase mTOR) and nebivolol (Neb: a 3
rd
generation β1 adrenergic receptor [β1-AR] blocker that exhibits β3-AR agonism) modulate miR-208a expression in cardiomyocytes.

Methods and Results:
In mouse atrial cardiomyocyte HL-1 cells, 12 hour treatment with Ang II (100nM) increased miR-208a by 6 fold as determined by real-time RT-PCR analysis (P<0.05; n=5). AT1 receptor (AT1R) blocker losartan (10μM), but not AT2 receptor (AT2R) blocker PD123319 (10μM), inhibited this effect. Pre-treatment (1hr) with Rap (10nM) and Neb (1μM), but not apocynin (500μM: NADPH oxidase inhibitor) or U73122 ((10μM: Phospholipase C inhibitor) attenuated Ang II-induced increases in miR-208a levels (P<0.05). Thus, the AT1R-mediated activation of mTOR up-regulates miR-208a in cardiomyocytes. Immunoblotting revealed that Ang II increased phosphorylation (p) of mTOR (pSer
2448
), S6K1 (pThr
389
) and RPS6 (pSer
235/236
) by 1.5 to 2 fold in HL-1 cells and Rap and Neb suppressed this effect (P<0.05). Neb-induced β3-AR agonism was not involved in miR-208a suppression since β3-AR antagonist SR52930 (1μM) did not reverse Neb-induced suppression of miR-208a and β3-AR mRNA was not detected in HL-1 cells by real time RT-PCR. Interestingly, a 12 hour treatment of HL-1 cardiomyocytes with 1μM Neb attenuated
125
I-Ang II binding to the AT1R by (70%: P<0.05); however a 15 minute pre-incubation with 1μM Neb did not prevent
125
I-Ang II binding to HL-1 cells. Thus, chronic Neb treatment down-regulates AT1R function in cardiomyocytes.

Conclusions:
We show for the first time that Ang II increases miR-208a expression in cardiomyocytes via activation of mTOR-S6K1 signaling pathway. Nebivolol, a β-blocker, inhibits Ang II-induced miR-208a expression and mTOR signaling. Moreover, chronic Neb treatment down-regulates AT1R in cardiomyocytes. Regulation of AT1R-mTOR-miR-208a axis by Neb is a novel cardioprotective mechanism.
Abstract 656: Behavior Of Endothelial Function And Blood Pressure After Use Of Spironolactone Or Clonidine In Patients With Resistant Hypertension
Authors: Bassan Fabiana B , Rodrigues Maria L , Valença Debora , Carvalho Renata , Soares Elaine , Torres Marcia , Neves Mario F , Oigman Wille , Sanjuliani Antonio F
Published: March 2022

Objective:
To evaluate the behavior of BP and endothelial function after spironolactone or clonidine, associated with optimized antihypertensive treatment in patients with resistant hypertension (PRH).

Methods:
Prospective and randomized study, visits every 4 weeks. VISIT (V) 0: Inclusion of patients with BP>160/100mmHg and <220mmHg. They receive chlorthalidone 25mg/day and Enalapril 40mg/day or Losartan 100mg/day. V1: If BP>140/90 amlodipine was added 5mg/day. Laboratory evaluation (LE), plasma renin and aldosterone and 20 min ECG, ABPM. V2: If BP>140/90 amlodipine titrated to 10mg/day. V3 (Randomization): ABPM, LE and assessment of endothelial function. If BP>140/90 and/or 24h ABPM>130/80 patients received spironolactone 12.5mg/day or clonidine 0.200mg/day. V4 and V5 (PRH): titration of clonidine (0.200mg to 0.600mg) or spironolactone (12.5mg to 50mg). V6: The same evaluation of V3. Patients with controlled BP in V3 have maintained their medication in V4, V5 and V6 and undergo the same tests that PRH. BP and ABPM was assessed by an automatic device; endothelial function by tonometry arteriolar peripheral (PAT) with Endo-PAT2000 ® and biomarkers (I-CAM, V-CAM, E-sel, PCR); plasma renin and aldosterone by RIA.

Results:
So far the study evaluated 46 patients where 28 patients had controlled BP and 13 remained resistant. In the spironolactone group the 24h-BP behavior, assessed by ABPM was SBP (V1) 162,8±7,9 and (V6) 124,3±3,7 (p<0,05), DBP (V1) 99,7±5,1 and (V6) 78,2±6,3 (p<0,05); while in the clonidine group SBP (V1) 158,8±11,7 and (V6) 134±19 (p<0,05), DBP (V1) 92±8,4 and (V6) 87,5±13,5 (p<0,05). In the controlled BP group SBP (V1) 134,4±2,7 and (V6) 124,3±3,1 (p<0,05), DBP (V1) 85,2±1,7 and (V6) 78,5±2,5 (p<0,05). The reactive hyperemia index (RHI) determined by the PAT in the spirolactone group was V3: 1,83 ± 0,13 and V6: 1,84 ± 0,2; clonidine group V3: 1,72 ± 0,22 and V6: 1,9 ± 0,6 and controlled BP group V3: 1,87 ± 0,08 and V6: 2,0 ± 0,12.

Conclusion:
Despite the statistically significant reduction of BP with spironolactone and clonidine, it seems that the improvement in endothelial function has been most pronounced in the clonidine group, although without statistical relevance.
Abstract 659: Chemerin Connects Fat to Blood Pressure
Authors: Watts Stephanie W , Thompson Janice M , Watson Ralph , Dorrance Anne M , Burnett Robert , Garver Hannah , Penfold Mark , Fink Gregory D
Published: March 2022

Obesity and hypertension have become comorbid in near epidemic proportion, yet their biological connection is still largely a mystery. We hypothesized that the peptide chemerin (TIG2) is a candidate for connecting fat deposits (both perivascular and visceral) to elevated blood pressure. The normal Sprague Dawley or deoxycorticosterone acetate salt (DOCA) rat was used as the model. Real time RT-PCR demonstrated that chemerin was synthesized in periadventitial fat (PVAT) around the aorta. Immunohistochemical experiments showed that the primary receptor for chemerin, ChemR23, was expressed in the tunica media and endothelial layer and not in resident inflammatory cells of the artery. The potent analog chemerin-9 (1 nM — 3 uM) caused a concentration-dependent isometric contraction in isolated aorta and superior mesenteric artery that was modest in tissues at baseline [∼6-11% phenylephrine (PE) maximum contraction] but significantly amplified in the presence of the nitric oxide synthase inhibitor nitro-L-arginine (LNNA; 2.5 fold increase in maximum), endothelial removal (5.95 fold increase) or agonist-induced tone (3.2 fold increase). Chemerin-induced contraction in tissues incubated with LNNA was concentration-dependently antagonized by the novel ChemR23 antagonist CCX832, demonstrating a new role for ChemR23. Arteries from the DOCA-salt hypertensive rat demonstrated endothelial dysfunction, and chemerin-induced maximum contraction from baseline was markedly increased in the aorta (DOCA = 16+3.6%, Sham = 6.7 + 2.2% PE contraction) and superior mesenteric artery (DOCA=57.9+12.8, Sham = 11.2+2.9 % PE contraction; p<0.05). These data support a new role for chemerin as a vasoactive substance and a potential connector of the biological activity of the adipose tissue and liver (sources of chemerin) to blood pressure regulation, especially in conditions of endothelial dysfunction.
Abstract 667: Aortic Remodeling in Angiotensin II Treated ACE2 Knockout Mice
Authors: Alhajoj Ahmad M , Alghamri Mahmoud , Cool David R , Grunwald William C , Elased Khalid M , Weir Nathan , Morris Mariana
Published: March 2022

Angiotensin converting enzyme 2 (ACE2) is a protective regulatory protein that catalyzes conversion of Ang II to Ang-(1-7). There is much information on ACE2’s role in cardiac and renal pathologies, but limited data on ACE2 in vasculature. The objective was to study the role of ACE2 in the Ang II response as related to aortic remodeling and inflammation using ACE2 knockout (KO) mice. Eight week (C57Bl/6) male ACE2 KO and wild type (WT) mice (n= 7-8) were infused with Ang II (1000 ng/kg/min, 4 wks). Aortic structure (collagen, dimension), oxidative stress, and inflammatory cytokines were measured. Results showed a significant decrease (
p
<0.05) in aortic luminal area in Ang II ACE2 KO over WT (74.51μm
2
/pixel vs. 91.50 μm
2
/pixel). Picrosirius red staining showed higher collagen in the outer aortic wall in Ang II infused ACE2 KO mice compared to Ang II WT (55% vs. 19%). Dihydroethidium (DHE) staining indicated marked elevation in superoxide generation following Ang II infusion in ACE2 KO (18%) compared to WT (7%). A BioPlex system was used to quantify a panel of 23 cytokines in aorta. It revealed higher macrophage inflammatory protein (MIP-1α) in Ang II ACE2 KO vs. Ang II WT mice (13.5 vs. 3.3 pg/ml). Two-way ANOVA showed a significant effect of treatment (
p
< 0.02) for interleukin 1-α (IL-1α). Findings indicate that the aorta is a target site for Ang II’s pathological effects, an action which involves ACE2.
Abstract 73: Selective Inhibition of COX-1 & 2 Results in Reprogramming of Adipocyte Gene Expression and Adipogenesis in Mesenchymal Stem Cells: Role of 20-HETE-derived 20-OH-PGE2
Authors: Kim Dong Hyun , Puri Nitin , Sodhi Komal , Schwartzman Michal L , Falck J , Abraham Nader G
Published: March 2022

Eicosanoids are increasingly recognized to play a central role in modulating the process of adipogenesis in human bone marrow derived mesenchymal stem cells (MSCs) where prostaglandin E2 (PGE2) has been shown to negatively regulate adipogenesis. 20-Hydroxyeicosatetraenoic acid (20-HETE), a product of the cytochrome P450 (CYP)-catalyzed ω-hydroxylation of arachidonic acid, induces oxidative stress, and in clinical studies, is associated with increased BMI and metabolic syndrome. In this study we sought to characterize the effects of exogenous 20-HETE on MSC-derived adipogenesis. 20-HETE dose-dependently (0.01-1 μM) increased (p<0.05) adipogenesis (0.11±0.001, 0.12±0.007, 0.14±0.015 and 0.16±0.013) in MSCs, an effect not attenuated by concurrent administration of a putative 20-HETE antagonist (DKB-H1-40-32). However, a selective cyclooxygenase-2 (COX-2) inhibitor prevented (0.071±0.004 vs 0.16±0.013) this pro-adipogenic effect of 20-HETE thus raising the possibility that a metabolic product of 20-HETE is mediating its effects on MSCs. We next exposed these MSCs to exogenous 20-OH-PGE2, an endogenous COX-2 derived product of 20-HETE. Treatment with 20-OH-PGE2 also dose-dependently enhanced (0.08±0.02, 0.14±0.01, 0.21±0.01 and 0.4±0.02) adipogenesis and lipid accumulation in MSC-derived adipocytes. In addition, in cells undergoing COX-1 &2 blockade, treatment of MSCs with PGE2 shifted the dose response curve of 20-OH-PGE2 to the right, indicative of a competitive antagonistic interactions of COX-1 derived PGE2 and COX-2-derived 20-OH-PGE2 on the process of adipogenesis. Both 20-HETE and 20-OH-PGE2-induced adipocyte hypertrophy was accompanied with increased expression of adipogenic regulators, PPARδ, C/EBPα and MEST1. Taken together we show for the first time that 20-HETE-derived COX-2-dependent 20-OH-PGE2 could enhance lipid accumulation and induces adipocyte hypertrophy in MSC undergoing adipogenic differentiation. We also propose that effects of COX-1 derived PGE2, a known inhibitor of adipocyte differentiation, are opposed by endogenous 20-OH-PGE2 production which appears to predominantly COX-2 dependent.
Abstract 78: Chronic Intrarenal Ghrelin Receptor Antagonism Delays the Onset and Attenuates the Magnitude of High Fat Diet-Induced Hypertension in Dahl Salt-Sensitive Rats
Authors: Kemp Brandon A , Howell Nancy L , Padia Shetal H
Published: March 2022

Excess weight gain contributes up to 65% of the risk of primary hypertension in developed countries and the increase in blood pressure (BP) in response to high-fat diet (HFD) is preceded by significant reductions in renal tubular sodium (Na
+
) excretion. In normal rats, direct renal infusion of ghrelin, the most potent appetite-stimulating hormone in the body, increases distal nephron-dependent Na
+
reabsorption via activation of ghrelin receptors (GR) in the kidney. The present study seeks to determine the role of intrarenal GR-mediated Na
+
reabsorption in HFD-induced hypertension. Dahl salt-sensitive rats (DSS) received standard diet (STD, 10% kcal fat, N=6) or HFD (42% kcal fat, N=14) for 6 weeks (WK). Prior to the initiation of the study, all DSS underwent a uninephrectomy and osmotic minipump implantation for chronic renal interstitial (RI) delivery of 5% dextrose in water (D
5
W, 0.25 μL/hr x 28-day) or selective GR antagonist [D-Lys-3]-GHRP-6 (D-LYS, Tocris, IC
50
=0.9 μmol/L, 5 mg over 28-day) into the remaining kidney. At the end of the study, pump patency and security of RI delivery was confirmed via direct visualization. DSS with D
5
W pumps (N=7) demonstrated a significant increase in mean systolic BP (SBP) after 2 WK on HFD (135±4.4 mmHg vs. 118±2.7 mmHg at baseline, *P<0.05) with a mean SBP of 150±3.9 mmHg by WK 6 (***P<0.001 from baseline). However, DSS with D-LYS pumps (N=7) for chronic RI GR antagonism during HFD failed to become hypertensive until WK 4 (134±3.9 mmHg vs. 121±3.3 mmHg at baseline, *P<0.05) and the mean SBP achieved at WK 6 was only 139±3.6 mmHg (
+
P<0.05 compared to HFD D
5
W pump rats). DSS fed a STD failed to develop significant hypertension and served as a time control group. HFD rats with D
5
W pumps demonstrated significantly reduced 24-hr urine Na
+
excretion
prior
to the onset of hypertension at WK 2 (0.94±0.15 vs. 1.35±0.09 μmol/min at baseline, *P<0.05). The reduction in Na
+
excretion failed to occur in DSS with a D-LYS pump (1.24 ±0.12 vs. 1.29±0.09 μmol/min at baseline, P=NS) despite exposure to the same HFD and identical weight gain. These results indicate that increased intrarenal GR-mediated Na
+
reabsorption contributes to the development of HFD-induced hypertension, offering a novel therapeutic target for obesity-induced hypertension.
Abstract 79: Knockdown of ACE2 in the Paraventricular Nucleus Partially Reverses the Protective Effects of Brain ACE2 in DOCA-salt Hypertension
Authors: Xia Huijing , Sriramula Srinivas , Lazartigues Eric
Published: March 2022

To identify which brain regions are critical for ACE2 regulation of blood pressure (BP), we generated transgenic mice harboring a loxP-flanked human ACE2 transgene specifically in the brain (hACE2
flox
) and tested the impact on DOCA-salt hypertension. hACE2
flox
and non-transgenic (NT) mice were implanted with telemetry probes for conscious BP monitoring. DOCA (1 mg/g, sc) was implanted following baseline BP recording and drinking water was replaced by 1% NaCl solution. Two weeks later, hACE2
flox
mice were divided into 2 groups (n=7/group) and injected bilaterally with an adenovirus encoding Cre recombinase (Ad-Cre) or a control virus (LacZ) to the paraventricular nucleus (PVN; 10
7
particles/200 nl; ±0.3 mm lateral, 0.6 mm caudal, 5.0 mm ventral). NT mice were also injected with LacZ. BP was continuously recorded for 1 more week. Autonomic function was analyzed using a pharmacological method involving ip injection of propranolol (4 mg/kg) and atropine (1 mg/kg). Changes in heart rate (ΔHR, bpm) were used as index of sympathetic and parasympathetic tones. Baseline mean BP was not different among NT+LacZ (105 ±3 mmHg), hACE2
flox
+LacZ (107 ±2 mmHg) and hACE2
flox
+Ad-Cre (106 ±2 mmHg) groups, nor was sympathetic (-91 ±4, -101 ±8, -101 ±14 bpm) or vagal tones (+169 ±7, +152 ±10, +168 ±9 bpm). Three weeks after DOCA-salt treatment, mean BP was dramatically increased in NT+LacZ mice (141 ±3 mmHg,
P
<0.01 vs. baseline) but only modestly increased in hACE2
flox
+LacZ mice (127 ±4 mmHg,
P
<0.05 vs. NT). In addition, cardiac sympathetic drive was significantly increased (-193 ±27 bpm,
P
<0.01 vs. baseline) while vagal tone was impaired (+113 ±11 bpm) in NT+LacZ mice. However, DOCA-salt-mediated autonomic dysfunction was prevented in hACE2
flox
+LacZ mice (sympathetic drive: -119 ±7 bpm, vagal tone: +146 ±9 bpm,
P
<0.05 vs. NT+LacZ). Selective knockdown of ACE2 in the PVN by Ad-Cre tended to increase BP (133 ±3 mmHg) and sympathetic activity (-168 ±35 bpm) as well as decrease vagal tone (+138 ±34 bpm) in hACE2
flox
, compared to LacZ transfected hACE2
flox
mice. These data suggest that ACE2 overexpression in the brain blunts the development of hypertension by preventing autonomic dysfunction, and PVN might not be essential for the ACE2-mediated blunting of neurogenic hypertension.
Abstract 8: Female Sex-related Cardioprotection Relies on Estrogen Receptor-beta, mTORC1, and mTORC2 Activities
Authors: Gürgen Dennis , Kusch Angelika , Klewitz Robin , Hegner Björn , Catar Rusan , Kintscher Ulrich , Luft Friedrich C , Dragun Duska
Published: March 2022

Normotensive deoxycorticosterone acetate-salt (DOCA) mice retain sexual dimorphism with adverse cardiac remodeling in males and maintenance of protective phenotype in females. Genomic deletion of ERβ in DOCA mice removed this protection. We hypothesized that sex differences in mTOR signaling branches are instrumental for ERβ-mediated cardioprotection in females. Female and male mice with ERα and ERβ gene deletions were uninephrectomized and treated with DOCA for 6 weeks. Hydralazine was used for blood-pressure normalization under telemetric control. Echocardiography was used to determine left ventricular dimensions and function. In additional studies, we used rapamycin to inhibit mTOR in wild-type (WT) mice. While ERα deletion had no significant impact on cardiac phenotype and function, ERβ
-/-
female DOCA mice showed the maladaptive cardiac phenotype as recently reported. Signal transduction analysis revealed high mTORC1 (pp70S6K
Thr389
) and mTORC2 (pAkt
Ser473
) activation in WT DOCA females, but not in WT DOCA males, which was also lost in DOCA ERβ
-/-
females. Rapamycin-treated male DOCA mice showed functional benefit from intervention and reduced left ventricular hypertrophy (LVH). Heart weight to tibia length (HW/TL; mg/mm) was as follows: control/DOCA 7.1±0.2 / 8.7±0.2, rapamycin control/DOCA 7.0±0.2 / 7.9±0.2) with preserved ejection fraction. This state-of-affairs was associated with increased mTORC2 activity as measured by pAkt
Ser473
upregulation (DOCA 0.8±0.2, rapamycin DOCA 2.2±0.3). In contrast, females displayed a further 14% LVH increase with rapamycin (HW/TL control/DOCA 6.4±0.1 / 7.4±0.1, rapamycin control/DOCA 6.1±0.2 / 7.9±0.2) and developed a dilative cardiac phenotype similar to ERβ
-/-
females (LVIDd [mm] DOCA/rapamycin DOCA 4.18±0.06 / 4.31±0.08, IVSd [mm] DOCA/rapa DOCA 0.6±0.02 / 0.5±0.02). Remarkably, in contrast to males, rapamycin intervention decreased not only mTORC1, but also mTORC2 activity in females (DOCA 1.7±0.2, rapamycin DOCA 0.9±0.1). Our findings implicate ERβ-dependent sex-specific regulation of mTOR signaling. Maintenance of mTORC1 and mTORC2 signaling appears to be essential for adaptive cardiac remodeling what provides a rationale for sex-specific therapeutic strategies in LVH.
Abstract 81: Activation of Microglia in the PVN Precedes Increase in Blood Pressure in Chronic Angiotensin II Infusion Rat Model of Hypertension
Authors: Santisteban Monica M , Jun Joo Y , Marulanda Carvajal Jessica , Zingler Michael , Zubcevic Jasenka , Qi Yanfei , Raizada Mohan K
Published: March 2022

Introduction:
Hypertension is the most important risk factor for cardiovascular disease. Dysregulation of the autonomic nervous system (ANS) with increased sympathetic stimulation is a hallmark of neurogenic hypertension, and has been shown to precede the rise in the blood pressure. We have previously shown that chronic Angiotensin II (Ang II) infusion increases blood pressure by activation of the microglia in the cardioregulatory brain regions, such as the paraventricular nucleus of the hypothalamus (PVN). Here, we studied the activation of microglia following 3- and 7-day Ang II infusion as a marker of neuroinflammation. We hypothesize that activation of the microglia in the PVN is a possible precursor to the ANS dysfunction and the blood pressure increase in Ang II-dependent hypertension.

Methods:
An osmotic minipump delivering either saline or 200ng/kg/min Ang II S.C. was implanted in 9-week old adult male Sprague-Dawley rats randomly assigned to control (saline), or 3-day or 7-day Ang II infusion (n=4) . Blood pressures were measured using radiotelemetry. CD11b immunoblotting of the PVN was used to assess the activated microglia in the PVN. Additionally, Iba1 immunohistochemistry of the PVN was used to image and quantify the increase in total size and number of activated microglia.

Results:
Despite no significant change in the blood pressure, we found a 1.40 fold increase in the CD11b protein quantity, and a 12% increase in microglia size at 3-days of Ang II infusion compared to control. At 7-days of Ang II infusion, we observed a 4.93 fold increase in the CD11b protein quantity, a 33% increase in microglia size, and a 29% higher number of microglia, which was accompanied by ∼ 25mmHg elevation in the blood pressure compared to control.

Conclusion:
These data suggests that microglia in the PVN become activated in as early as 3-days following Ang II infusion, before the blood pressure changes occur. Therefore, activation of microglia precedes the increase in blood pressure. This implicates the microglia in the dysregulation of the ANS in Ang II hypertension.
Abstract 90: Loss of Collectrin Augments Salt-sensitivity and Alters Nitric Oxide and Superoxide Balance.
Authors: Cechova Sylvia , Rudy Christine K , Zeng Qing , Chan Fang R , Howell Nancy L , Carey Robert M , Le Thu H
Published: March 2022

Collectrin, an ACE-2 homologue, plays a major role in amino acid transport in renal epithelial cells. In the rodent kidney, the expression of collectrin is upregulated after reduction of nephron mass and during salt-sensitive hypertension. These observations raise the question of how collectrin might be functionally integrated in the ACE family in the context of blood pressure (BP) regulation. We previously reported that, on a susceptible genetic background, collectrin-deficient (KO) mice have elevated baseline systolic blood pressure (SBP) and impaired endothelium-dependent relaxation (EDR) of thoracodorsal arteries (TDA). Treatment with L-NAME, a nitric oxide synthase (NOS) inhibitor, normalized their BP and EDR of TDA. Here, to determine whether collectrin plays a role in salt-sensitivity (SS), we fed mice a high salt diet (HSD) for 2 weeks. By radiotelemetry, KO mice displayed augmented salt-sensitivity (SS) (Normal salt (NS): Wild-type (WT) 133 ± 1 mm Hg, KO 141 ± 3 mm Hg; HSD: WT 141 ± 2 mm Hg, KO 155 ± 3 mm Hg; change in SBP: WT 7.8 ± 1.4 mm Hg, KO 14.4 ± 1.5 mm Hg; p ≤ 0.02), and lower urinary sodium excretion (UNa) during the first 3 days of HSD (mean UNa over 3 days: KO: 1980 ± 193 μmol/24h, WT: 2650 ± 98 μmol/24h, p = 0.006, ANOVA; n ≥ 6). The impaired pressure natriuresis in KO mice was associated with altered urinary excretion of 8-isoprostane F
2
α
(WT 3.0 ± 0.67 ng/mg, KO 7.7 ± 1.5 ng/mg creatinine, p = 0.008) and nitrates/nitrites (WT 10.2 ± 1.4 nmol/day, KO 6.2 ± 0.61 nmol/day, p = 0.03, n ≥ 4 each). We previously reported that KO mice have increased state of endothelial NOS (eNOS) uncoupling. Here, by immunostaining, we found that collectrin is expressed in endothelial cells (ECs). We next queried whether collectrin affects L-arginine (L-Arg) transport in ECs. After isolation from the pulmonary artery, primary ECs from KO mice displayed impaired [
3
H]L-Arg uptake (WT 2.00 ± 0.19, KO 0.90 ± 0.06 pmol/mg protein/min, p=0.01) To establish direct cause and effect, we over-expressed collectrin in primary human coronary ECs which resulted in increased [
3
H]L-Arg uptake (Control 4.20 ± 0.32; Overexpression 6.60 ± 0.59 pmol/mg protein/min, p < 0.003). In conclusion, collectrin may regulate BP and SS by modulating the balance of NO and SO through its role in L-Arg transport in ECs.
Abstract 94: Scaffolding Protein EBP50 Regulates Vascular Smooth Muscle Nox1 Activity by Binding p47
phox
Authors: Al Ghouleh Imad , Song Gyun Jee , Bisello Alessandro , Pagano Patrick J
Published: March 2022

The NADPH oxidase (Nox) enzyme family is implicated in the pathogenesis of cardiovascular diseases (CVDs) including hypertension. In large vessel smooth muscle cells (SMCs), a unique hybrid Nox1 oxidase exists which propagates SMC dysfunction and hypertrophy. We recently demonstrated that these actions involve activation of Nox1 by hydrogen peroxide (H
2
O
2
) leading to feed-forward production of reactive oxygen species and activation of apoptosis signal regulating kinase 1 (Ask1). Here we postulate that Ezrin-radixin-moesin-binding phosphoprotein 50 (EBP50), a PDZ-domain scaffolding protein, is required for H
2
O
2
-mediated activation of SMC Nox1. In SMCs, knockdown of EBP50 by shRNA abolished superoxide (O
2
•-
) production in 50 μM H
2
O
2
-treated cells (37.7 ± 4.5, 79.9 ± 2.3 and 29.0 ± 3.5 x10
4
O
2
•-
-mediated RLU for GFP plasmid vehicle-treated, GFP plasmid H
2
O
2
-treated and EBP50 shRNA plasmid H
2
O
2
-treated groups, respectively). Furthermore, H
2
O
2
-induced O
2
•-
production was absent in SMCs isolated from EBP50 knockout (KO) mice (29.0 ± 2.7 vs 79.1 ± 2.4 x10
4
RLU for EBP50 KO vs wildtype after H
2
O
2
treatment). Intriguingly, p47

phox

, an essential cytosolic subunit of the hybrid SMC Nox1 system, upon phosphorylation co-immunoprecipitated with EBP50 in COS-7 cells transfected with both proteins (Fig 1). Taken together, our data suggest that EBP50 promotes Nox activity by binding active p47

phox

. These studies identify a novel partner in Nox1 activation and potentially provide new insights into the broader regulation of this enzyme family. Moreover, this added level of complexity could yield new therapeutic strategies to disrupt Nox in the treatment of hypertension and other CVDs.
Abstract 10: Complement C3a Receptor Antagonist Attenuates Placental Ischemia-induced Hypertension in Rat
Authors: Regal Jean F , Lillegard Kathryn E , Elmquist Barbara J , Bauer Ashley J , Johnson Alex C , Opacich Jonathan W , Peterson Jenna M , Gilbert Jeffrey S
Published: March 2022

Preeclampsia, a leading cause of maternal death and premature birth, is characterized by hypertension, compromised placental perfusion and intrauterine growth restriction. The complement system, part of the innate immune system, is activated in normal pregnancy with increased activation apparent in preeclampsia. We recently reported that inhibiting complement system activation with a soluble form of endogenous complement receptor significantly attenuated reduced uterine perfusion pressure (RUPP)-induced hypertension in the pregnant rat without affecting fetal resorptions or decreased circulating vascular endothelial growth factor. Since the vasoactive complement activation product C3a increased in serum following placental ischemia, we hypothesized that C3a is an important mediator of placental ischemia-induced hypertension. Using the RUPP model of hypertension in preeclampsia, we determined the effect of the C3a receptor antagonist SB290157 (N2-[(2,2-Diphenylethoxy)acetyl]-L-arginine) on changes in blood pressure and fetal weight following placental ischemia. On gestation day 14, clips were placed on abdominal aorta and uterine arteries to decrease placental perfusion. All dams received 5 mg/kg SB290157 or 10% ethanol/saline (Veh) iv on days 14-18. Mean arterial pressure (MAP) was measured on day 19 via arterial catheter and fetal weights were subsequently assessed. SB290157 treatment of rats that underwent sham surgery (Sham SB, n=6) did not affect either MAP or fetal weights compared to Sham Veh. MAP increased in RUPP Veh rats compared to Sham Veh (RUPP Veh, n=7, 109±2 mm Hg; Sham Veh, n=7, 94±2; p<0.05) and average fetal weights decreased (Sham Veh, 2.52±0.07 g; RUPP Veh, 2.24±0.07 g; p<0.05). Treatment of RUPP rats with SB290157 attenuated increased MAP (RUPP Veh, 109±2 mm Hg; RUPP SB, n=9, 101±2; p<0.05) but did not prevent decreased fetal weight (RUPP Veh, 2.24±0.07 g; RUPP SB, 2.20±0.07 g). These data suggest C3a is partly responsible for placental ischemia-induced hypertension and provide important new evidence to support a link between complement activation and hypertension. Inhibitors of complement activation or C3a antagonists may be viable new treatment strategies for managing new-onset hypertension in preeclampsia.
Abstract 15: Loss of Tumor Suppressor Protein p53 is linked to High Blood Pressure
Authors: Liu Jiao , Li Wencheng , Li Yuwen , Chen Tianjian , El-Dahr Samir , Feng Yumei , Saifudeen Zubaida
Published: March 2022

Emerging evidence suggests that chronic inflammation plays a critical role in the development of hypertension. The tumor suppressor protein p53 is a key regulator of inflammation pathways. We therefore hypothesized that loss of p53 activity increases blood pressure (BP) by unleashing inflammatory responses. To test this hypothesis 8-week old p53-null (p53
-/-
) and wild-type mice (N=6, each group) were implanted with telemetry transmitters into the carotid arteries. After a 2 week recovery period post-surgery, BP was recorded continuously for 72 hours. Autonomic functions were assessed using IP administration of Methylatropine (dose 1mg/kg), propranolol (6mg/kg), and ganglionic blocker chlorisondamine (5mg/kg). Daytime BP (MAP: 109.4±2.3 vs. 95.5±1.1mmHg) is significantly higher in p53
-/-
mice compared to wild-type mice (P< 0.05). Heart rate (HR) response to propranolol was significantly greater in p53
-/-
mice (delta HR: 89.9±13.2bpm) compared to wild-type mice (delta HR: 45.9±7.8bpm, P<0.05) indicating that p53
-/-
mice have greater cardiac sympathetic tone. Furthermore, the BP response to chlorisondamine is greater in p53
-/-
mice (delta BP: 43.3±2.6mmHg) compared to wild-type mice (delta BP: 20.7±2.0mmHg, P<0.01), suggesting that p53
-/-
mice harbor higher vasomotor sympathetic tone. To gain insight into the involvement of neural components in elevating BP in the null mice, transcriptome analysis was done on hypothalamic genes. Gene Ontological Biological Process (GO_BP) classification of differentially regulated genes revealed genes involved in immune response and inflammation. These includes chemokine ligand 17 (1.8 fold increase, P<0.05), tumor necrosis factor receptor 1B (2.2 fold increase, P<0.05), and nerve growth factor receptor (TNFR superfamily, member 16, Ngfr) (1.5 fold increase, P<0.05). In summary, p53 deletion increases BP, HR, and cardiac and vasomotor sympathetic activity and is associated with increases in genes involved in immune response and inflammatory pathways in the hypothalamus of the brain. These data provide a hitherto unrecognized link between tumor suppression, inflammation and blood pressure.
Abstract 157: MAP Kinase Phosphatase-1 Inhibitor Injection into the Solitary Tract Nucleus Impairs Cardiovagal Baroreflex Function in Transgenic ASrAOGEN Rats
Authors: Nautiyal Manisha , Tommasi Ellen , Chappell Mark C , Diz Debra I
Published: March 2022

Hypotensive transgenic ASrAOGEN rats (AS) with low brain angiotensinogen resulting from glial overexpression of an antisense oligonucleotide to angiotensinogen, have enhanced baroreflex sensitivity (BRS) relative to hypertensive transgenic (mRen2)27 rats (mRen) that overexpress the murine Ren2 gene or normotensive Sprague Dawley rats (SD). The AS rats exhibit elevated protein expression and activity (less phosphorylated-ERK) of the MAP Kinase Phosphatase-1 [MKP-1], a negative regulator of MAP Kinase signaling in the brain dorsal medulla compared with either mRen or SD rats at 26 wks of age. To determine if MKP-1 plays a role in maintenance of BRS, we gave acute bilateral microinjections of an irreversible MKP-1 inhibitor {2,3-bis-[(2-Hydroxyethyl)thiol]-1,4-naphthoquinone, NSC 95397; 200 nM/120 nL} into the solitary tract nucleus (NTS), an important site in the dorsal medulla for modulation of BRS in urethane/chloralose anesthetized AS, mRen and SD rats at 21 wks of age. The MKP-1 inhibitor impaired the BRS for bradycardia in response to increases in pressure by 48 % at 10 min (1.01 ± 0.16 baseline vs. 0.49 ± 0.1 msec/mm Hg at 10 min), 56 % at 60 min and 64 % at 120 min in the AS rats (p = 0.02, n = 8), but not in the mRen or SD rats. In addition, NSC 95397 reduced resting pressure (91 ± 3 at baseline vs. 79 ± 3 at 60 min vs. 80 ± 3 mm Hg at 120 min) in the SD rats, with a similar trend in the other strains, without effects on resting heart rate in any strain. Thus, up-regulated expression of MKP-1 contributes to the higher resting BRS function in AS rats. AS animals are spared age-related declines in BRS and they maintain higher expression of MKP-1 protein in the dorsal medulla vs. either mRen or SD rats (AS: 1.6 ± 0.2, mRen: 0.8 ± 0.1, SD: 1 ± 0.1 arbitary units; p = 0.01, n = 6 per group) at 66 wks of age. Thus, higher MKP-1 may be involved the preservation of BRS in older AS rats, suggesting the phosphatase be a novel therapeutic target to improve BRS function in aging and hypertension.
Abstract 159: Inhibition of Ace Does Not Prevent 20-hete-mediated Vascular Injury in Cyp4a12tg Mice
Authors: Garcia Victor , Ding Yan , Joseph Gregory , Capdevila Jorge H , Abraham Nader G , Falck John , Schwartzman Michal L
Published: March 2022

20-hydroxyeicosatetraenoic acid (20-HETE), a cytochrome P450-arachidonic acid metabolite in the microcirculation, increases smooth muscle contraction and proliferation, stimulates endothelial dysfunction and activation and promotes hypertension that is dependent, in part, on the renin angiotensin system (RAS). We showed that in cultured human microvascular endothelial cells, 20-HETE increases angiotensin converting enzyme (ACE) mRNA by 3.1-fold (± 0.16; p<0.05), ACE protein by 4.2-fold (±0.99; p<0.05) and cellular and extracellular ACE activity by 2.2-fold (±0.09; p<0.05) and 1.96-fold (±0.16; p<0.05), respectively. The contribution of ACE to vascular 20-HETE-mediated microvascular remodeling in hypertension was assessed using the Cyp4a12 transgenic mouse in which the expression of the Cyp4a12-20-HETE synthase is driven by a tetracyclin (doxycycline, DOX)-sensitive promoter. Treatment of Cyp4a12tg mice with DOX increased blood pressure (133±6 vs. 107±3 mmHg; p<0.05) and remodeling of renal resistance arteries (M/L, 0.15±0.01 vs. 0.07±0.01; p<0.05); these increases were abrogated by co-treatment with the 20-HETE antagonist, 20-HEDGE. Renal ACE protein expression was significantly higher in DOX-treated (1.6 ± 0.17 fold; p<0.05) as compared to untreated Cyp4a12tg mice; co-treatment with 20-HEDGE prevented the increase in ACE expression. Lisinopril treatment of Cyp4a12tg mice concurrently receiving DOX prevented the blood pressure increase (133±6 vs. 104±2 mmHg; p<0.05) but did not interfere with renal microvascular 20-HETE production (1.05±0.18 vs 1.09±0.30 ng/mg). Co-treatment with lisinopril and DOX attenuated but did not prevent remodeling of renal microvessels (M/L, 0.07±0.0 vs. 0.15±0.01 vs. 0.11±0.01; p<0.05 in water, DOX and DOX+Lisinopril, respectively). In contrast, co-treatment with 20-HEDGE prevented DOX-induced remodeling of resistance arteries of Cyp4a12tg mice. This study demonstrates that 20-HETE is a key determinant of microvascular remodeling in DOX-induced Cyp4a12tg hypertensive mice. 20-HETE’s mechanism only partially relies on activation of the RAS. Thus, the 20-HETE-driven microvascular remodeling does not fully depend on the upregulation of ACE and elevation of blood pressure.
Abstract 160: Angiotensin-(1-7) Decreases the Pro-inflammatory Effects of Prorenin in Hypothalamic Microglia
Authors: Liu Meng , Shi Peng , Sumners Colin
Published: March 2022

The chronic hypertensive action of angiotensin II (Ang II) mediated within central cardiovascular control centers includes a pro-inflammatory effect and induction of microglial activation in the paraventricular nucleus (PVN) of the hypothalamus. The objective here was to investigate whether angiotensin-(1-7), a protective arm of the renin-angiotensin system (RAS), can exert anti-inflammatory effects in hypothalamic microglia. The presence of Mas, the receptor for Ang-(1-7), within the PVN and other cardiovascular control centers of normotensive (SD; Sprague Dawley) rats was demonstrated by quantitative real time PCR analyses. Mas was maintained in microglial cultures prepared from the hypothalamus of SD rat pups based on immunostaining and PCR. Treatment of microglial cultures with Ang-(1-7) (100nM, 3 -12h) elicited time-dependent significant (P<0.05) decreases in the basal levels of mRNAs for the pro-inflammatory cytokines interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor-necrosis factor α (TNFα), and in the microglial-macrophage marker CD11b. For example, the levels of IL-1β mRNA (normalized to GAPDH) within control and Ang-(1-7) treated cells were 1.0±0.09, 0.70±0.06, 0.40±0.04, and 0.48±0.07 (n=6). There was no significant effect of Ang-(1-7) on basal IL-1β mRNA at 10 nM (6h), and 1000 nM Ang-(1-7) produced no greater effect than 100 nM of this peptide. Treatment of cultures with the RAS component prorenin (PRO; 10, 20 or 50 nM; 6h) elicited highly significant (P<0.001) increases in IL-1β mRNA (4.2±0.10, 7.4±0.35, 16.7±0.46, respectively, n=6) when compared with controls (0.78±0.06), effects that far exceeded the ~2.0 fold increase in IL-1β mRNA elicited by Ang II (100 nM). Similar stimulatory effects of PRO on TNFα, IL-6 and CD11b mRNAs were also observed. The stimulatory action of PRO (10 nM) on IL-1β and TNFα mRNAs, but not CD11b mRNA, was attenuated by co-treatment with Ang-(1-7) (100 nM). For example, levels of IL-1β mRNA in PRO and Ang-(1-7)/PRO treated cells were 34.1±1.3 and 24.4±1.1 respectively (n=6), a reduction of ~29% (P<0.001). Collectively, these data suggest that Ang-(1-7) exerts a direct anti-inflammatory action at hypothalamic microglia, and inhibits PRO-induced pro-inflammatory effects.
Abstract 164: Disorder of Fatty Acid Oxidation in the Kidney of Rats With Angiotensin II-Induced Hypertension
Authors: Rong Rong , Ito Osamu , Muroya Yoshikazu , Kohzuki Masahiro
Published: March 2022

Abnormal lipid metabolism is common in patients with hypertension and chronic renal failure. Angiotensin II (Ang II) treatment causes high blood pressure and lipid accumulation in the kidney of rats. However, the mechanism of the Ang II-induced lipid accumulation in the kidney is not fully clarified. The present study was designed to examine changes of fatty acid metabolism in the kidney of Ang II-treated rats. Male Sprague-Dawley rats were treated with vehicle or Ang II (400ng/kg/min) by using osmotic mini-pumps for 7 days. The protein expression of enzymes associated with fatty acid metabolism in the kidney was analyzed by using immunoblot ananlysis. After 7 days, Ang II treatment significantly increased the systolic blood pressure (112.0±2.8mmHg versus 134.6±3.4mmHg; P<0.01) and urinary albumin excretion (21.1±0.9 versus 473.8±143.7μg/mg creatinine; P<0.05), but did not affect plasma creatinine. Ang II treatment significantly decreased the medium-chain acyl-CoA dehydrogenase (MCAD), very long-chain acyl-CoA dehydrogenase (VLCAD) (mitochondrial β-oxidation enzymes), cytochrome P-450 (CYP)4A1, and CYP4A2 (microsomal ω-oxidation enzymes) expressions by 20%, 19%, 31% and 17% (P<0.01) in the cortex. It also significantly decreased the MCAD, CYP4A1, CYP4A2 by 38%, 55%, 54% (P<0.01) in the outer medulla, but did not affect the VLCAD expression. In addition, Ang II treatment decreased the peroxisome proliferator-activated receptor (PPAR-α; a nuclear receptor regulating fatty acid oxidation) expression by 30% (P<0.05) in the outer medulla. It did not affect the PPAR-α expression in the cortex and the PPAR-γ coactivator-1α (PGC-1α; a regulator of mitochondrial function) expression both in the cortex and medulla. These data indicate that Ang II down-regulates the MCAD, VLCAD, CYP4A and PPAR-α expressions in the kidney. The suppressed fatty acid oxidation by Ang II may probably cause the renal lipid accumulation, associated with the development of hypertensive kidney damage.
Abstract 179: ACE2 Overexpression Prevents DOCA-Salt Hypertension by Modulating Cyclooxygenase Mediated Neuro-inflammation in the Central Nervous System
Authors: Sriramula Srinivas , Xia Huijing , Lazartigues Eric
Published: March 2022

DOCA-salt hypertension, a low-renin hypertension model, is mediated through activation of the renin angiotensin system within the brain and is mediated by inflammation. We previously reported that central Angiotensin Converting Enzyme 2 (ACE2) overexpression prevents the development of hypertension induced by DOCA-salt in a transgenic mouse model (syn-hACE2; SA) with human ACE2 targeted selectively to neurons. The present study examined whether ACE2 modulates cyclooxygenase (COX)-mediated neuro-inflammation in DOCA-salt-mediated hypertension. DOCA-salt treatment (1 mg/g body weight DOCA, 1% saline in drinking water, 3 weeks) of non-transgenic (NT) and SA mice produced a significant hypertension (MAP; telemetry) in NT (138 ±3 mmHg, n=8, p<0.05) that was blunted in SA mice (122 ±3 mmHg, n=12, p<0.05). NT mice treated with DOCA-salt showed increased inflammation as indicated by increased gene expression of TNF (3 fold, n=9, p<0.001
vs.
NT), IL-1beta (8 fold, n=9, p<0.001
vs.
NT) and IL-6 (5 fold, n=9, p<0.01
vs.
NT) in the hypothalamic paraventricular nucleus (PVN) which was attenuated in SA mice. Furthermore, DOCA-salt hypertension resulted in increased expression of COX-1 (2.5 fold, n=9, p<0.001
vs.
NT) and COX-2 in the PVN (5 fold, n=9, p<0.05
vs.
NT) and this increase was prevented by ACE2 overexpression. ACE2 overexpression also prevented DOCA-salt induced increases in EP1 (1.5 fold, n=9, p<0.01
vs.
NT) and EP3 (1.5 fold, n=9, p<0.01
vs.
NT) receptors expression in the PVN. Taken together, these data provide evidence that brain ACE2 prevents COX mediated neuro-inflammation, thereby preventing the development of DOCA-salt hypertension.
Abstract 18: Improvement of Autonomic Control in Spontaneously Hypertensive Rats: Sequential Effects of Training and Mechanisms Involved
Authors: Michelini Lisete C , Masson Gustavo S , Costa Tassia S , Ceroni Alexandre , Yshi Lidia , Soares Pedro P , Fernandes Denise , Laurindo Francisco R , Scavone Cristoforo
Published: March 2022

Aim:
Previous studies suggested that down-regulation of brain RAS and normalization of pro-inflammatory cytokines (PICs) expression contributed to reverse cardiovascular deficits in trained SHR. We investigate possible mechanisms involved and the sequence of their appearance within the paraventricular nucleus (PVN)

Methods:
SHR, submitted to treadmill training (T) or kept sedentary (S), were chronically instrumented for pressure (AP), heart rate (HR) and baroreflex sensitivity (BrS) recordings on weeks 0, 1, 2, 4 and 8 of protocols. After euthanasia fresh brains were removed and PVN dissected to quantify NADPH oxidase and PICs gene expression (real time PCR), DHE oxidation (HPLC), MAPKs phosphorylation (Western Blotting) and NF-kB activity (electrophoretic mobility shift assay); fixed brains were used for PVN PICs immunofluorescence (if). WKY served as time controls. One- or two-way ANOVA (Fisher as post-hoc test) were used

Results:
SHR-S vs WKY-S exhibited higher MAP and HR and decreased BrS (170±3 mmHg, 356±7 b/min; 2.31±0.19 b/min/mmHg, corresponding to +43%, +17% and -36%, respectively). SHR-S showed within the PVN increased expression of either p47 NADPH oxidase (2.3±0.2 vs 1.2±0.4 AU), DHE oxidation products (1267±122 vs 300±55 EOH/DHE/μg protein), NFkB binding to the DNA (100 vs 56±20%), TNFα and IL-6 gene & protein expression (1.9±0.3 vs 1.2±0.1 and 4.9±0.8 vs 1.1±0.3 AU, respectively), but normal phospho/total MAPKs. In the SHR, T normalized BrS (4.0±0.2 b/min/mmHg, T2-T8) simultaneously with normalization of both p47phox expression and superoxide content and a marked reduction of phospho/total ERK1/2 expression and NFkB activity. PICs (mRNA & if) were also normalized in SHR-T (T2-T8). These changes preceded a marked decrease on resting HR (T4-T8, with increased HF component of HR variability) and MAP fall simultaneously with reduced LF component of pressure variability, observed only at T8

Conclusions:
Data indicate that normalization of oxidative stress and pro-inflammatory profile and reduced ERK1/2 signaling within the PVN are important mechanisms to correct BrS in the trained SHR even in the presence of hypertension. Improvement of baroreflex allows a better vagal control of the heart and abrogates sympathetic vasomotor drive
Abstract 183: Chronic Systemic CB1 Cannabinoid Receptor Blockade Reduces Blood Pressure and Weight Gain and Improves Baroreflex Function and Heart Rate Variability in Hypertensive (mRen2)27 Rats
Authors: Schaich Chris L , Shaltout Hossam A , Howlett Allyn C , Diz Debra I
Published: March 2022

The effect of the endocannabinoid system (ECS) on weight and energy metabolism is well accepted, but long term contributions of the ECS to cardiovascular regulation are not established. Evidence for receptor and signaling interactions between the ECS and the renin-angiotensin system (RAS) in brain and vasculature is emerging. In transgenic (mRen2)27 rats, a monogenetic angiotensin (Ang) II-dependent model of hypertension with increased body mass, acute blockade of CB1 receptors in the solitary tract nucleus (NTS) restores the impaired baroreflex sensitivity (BRS) for control of heart rate to normal levels. We interpret these data as evidence for upregulation of the ECS in brain of this RAS-dependent model of hypertension. Data from the acute studies prompted us to study the effects of chronic systemic CB1 receptor blockade in (mRen2)27 rats using rimonabant (SR141716A), an orally active antagonist with central and peripheral actions. Beginning at 16 weeks of age animals were given daily oral injections of SR141716A (10 mg/kg/day; n = 6) for 28 days. In comparison to rats receiving vehicle (0.1% Tween-80 in dH2O; n = 6), daily dosing of SR141716A significantly reduced systolic blood pressure within 1 wk and by day 25 values were 172 ± 1 in control vs. 151 ± 5 mmHg in treated rats (P < 0.01). This was accompanied by decreased cumulative weight gain (44 ± 3 vs. 26 ± 2 grams, P < 0.01) and adiposity index (2.8 ± 0.2 vs. 1.9 ± 0.2% of body weight, P < 0.05) without long-term changes in food or water consumption. At the end of the study, conscious pressure recordings were obtained via arterial catheter for spectral and sequence analysis of autonomic tone. Two-fold increases occurred in Sequence ALL (P < 0.05) and indices of vagal and sympathetic BRS, as well as in heart rate variability (SDRR, P < 0.01), a measure of vagus nerve tone. The chronic beneficial actions of SR141716A in (mRen2)27 animals are consistent with the interpretation that an upregulated ECS contributes to maintenance of hypertension and impaired BRS in this RAS-dependent model. We conclude that systemic blockade of CB1 receptors, perhaps in part via actions within the NTS, is an effective therapy for lowering blood pressure and body weight, with a concomitant positive influence cardiovagal reflexes in hypertension.