Apelin-13 and APJ in paraventricular nucleus contribute to hypertension via sympathetic activation and vasopressin release in spontaneously hypertensive rats

2014 ◽  
Vol 212 (1) ◽  
pp. 17-27 ◽  
Author(s):  
F. Zhang ◽  
H.-J. Sun ◽  
X.-Q. Xiong ◽  
Q. Chen ◽  
Y.-H. Li ◽  
...  
Keyword(s):  
Paraventricular Nucleus ◽  
Spontaneously Hypertensive Rats ◽  
Sympathetic Activation ◽  
Hypertensive Rats ◽  
Vasopressin Release ◽  
Spontaneously Hypertensive

scholarly journals Exacerbated pressor and sympathoexcitatory effects of central Elabela in spontaneously hypertensive rats

2020 ◽  
Vol 318 (1) ◽  
pp. H124-H134 ◽  
Author(s):  
Zhi Geng ◽  
Chao Ye ◽  
Ying Tong ◽  
Feng Zhang ◽  
Ye-Bo Zhou ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Sympathetic Nerve ◽  
Spontaneously Hypertensive Rats ◽  
Sympathetic Nerve Activity ◽  
Akt Pathway ◽  
Sympathetic Activation ◽  
Hypertensive Rats ◽  
Nerve Activity ◽  
Vasopressin Release ◽  
Spontaneously Hypertensive

Elabela (ELA) is a newly discovered peptide that acts as a novel endogenous ligand of angiotensin receptor-like 1 (APJ) receptor. This study was designed to evaluate the effects of ELA-21 in paraventricular nucleus (PVN) on blood pressure and sympathetic nerve activity in spontaneously hypertensive rats (SHR). Experiments were performed in male Wistar-Kyoto rats (WKY) and SHR. ELA expression was upregulated in PVN of SHR. PVN microinjection of ELA-21 increased renal sympathetic nerve activity (RSNA), mean arterial pressure (MAP), heart rate (HR), plasma norepinephrine, and arginine vasopressin (AVP) levels in SHR. Intravenous injection of ELA-21 significantly decreased MAP and HR in both WKY and SHR, but only induced a slight decrease in RSNA. APJ antagonist F13A in PVN abolished the effects of ELA-21 on RSNA, MAP and HR. Intravenous infusion of both ganglionic blocker hexamethonium and AVP V1a receptor antagonist SR49059 caused significant reduction in the effects of ELA-21 on RSNA, MAP and HR in SHR, while combined administration of hexamethonium and SR49059 abolished the effects of ELA-21. ELA-21 microinjection stimulated Akt and p85α subunit of phosphatidylinositol 3-kinase (PI3K) phosphorylation in PVN, whereas PI3K inhibitor LY294002 or Akt inhibitor MK-2206 almost abolished the effects of ELA-21 on RSNA, MAP, and HR. Chronic PVN infusion of ELA-21 induced sympathetic activation, hypertension, and AVP release accompanied with cardiovascular remodeling in normotensive WKY. In conclusion, ELA-21 in PVN induces exacerbated pressor and sympathoexcitatory effects in hypertensive rats via PI3K-Akt pathway. NEW & NOTEWORTHY We demonstrated that PVN microinjection of ELA-21 increases sympathetic nerve activity and blood pressure, which can be abolished by pretreatment of APJ antagonist. This is the first demonstration that central ELA can induce hypertension. The pressor effects in PVN are mediated by both sympathetic activation and vasopressin release via PI3K-Akt pathway. Our data confirm that ELA is upregulated in the PVN of SHR and so may be involved in the pressor and sympathoexcitatory effects in hypertension.

Abstract 1378: NFkb Blockade Attenuate Cytokines And Oxidative Stress In The Paraventricular Nucleus And Decreases Neurohumoral Excitation In Spontaneously Hypertensive Rats

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Nithya Mariappan ◽  
Carrie Elks ◽  
Masudul Haque ◽  
Philip J Ebnezer ◽  
Elizabeth McIIwain ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Blood Pressure ◽  
Paraventricular Nucleus ◽  
Spontaneously Hypertensive Rats ◽  
Left Ventricular ◽  
Oxidative Stress Markers ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Stress Markers ◽  
And Oxidative Stress

The transcriptional factor, nuclear factor kappa B (NFkB) plays an important role in the regulation of cytokines. Among the cytokines, tumor necrosis factor-alpha (TNF) plays an important role in cardiovascular pathophysiology. This study was done to determine whether TNF-α blockade with etanercept (ETN) or NFkB blockade with dithiol pyrolidine thiocarbamate (PDTC) attenuate oxidative stress in the paraventricular nucleus (PVN) and contribute to neurohumoral excitation in spontaneously hypertensive rats. Method: Male 20 week old SHR rats were treated with ETN (1 mg/kg BW, sc) or PDTC (100mg/kg BW, ip) for 5 week period. Left ventricular function was measured at baseline (20 weeks) and at 25 weeks using echocardiography. Blood pressure was measured at weekly intervals throughout the study. At the end of the protocol rats were sacrificed the PVN was microdissected for the measurement of cytokines, oxidative stress markers using real time PCR (fold increase compared to WKY controls) and by immunohistochemistry. Superoxide, total reactive oxygen species and peroxynitrite were measured in the PVN and LV using electron paramagnetic resonance. Plasma norepinephrine and epinephrine an indicator of neurohumoral excitation was measured using HPLC-EC. Results: PVN data are tabulated. SHR animals had increased expression of protein and mRNA for cytokines and oxidative stress markers in the PVN and LV with increased MAP and cardiac hypertrophy when compared to WKY rats. Treatment with ETN and PDTC attenuated these increases with PDTC showing marked effect than ETN on hypertrophy and blood pressure responses. Conclusion: These findings suggest that cytokine activation in the PVN contributes to increased oxidative stress and neurohumoral excitation in hypertension.

Norepinephrine levels in paraventricular nucleus of spontaneously hypertensive rats: role of neuropeptide Y

1993 ◽  
Vol 265 (3) ◽  
pp. H893-H898 ◽  
Author(s):  
N. D. Woo ◽  
K. Mukherjee ◽  
P. K. Ganguly
Keyword(s):  
Neuropeptide Y ◽  
Paraventricular Nucleus ◽  
Spontaneously Hypertensive Rats ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Central Neurons ◽  
Sympathetic Regulation ◽  
Series Of Experiments ◽  
Wistar Kyoto

Recent evidence supports the view that the sympathetic system actively participates in the development of hypertension. Because norepinephrine, contained within central neurons involved in cardiovascular sympathetic regulation, is known to coexist with neuropeptide Y, it is possible that a functional interaction between neuropeptide Y and norepinephrine exists within the brain. In an effort to clarify whether or not central catecholamine systems are modulated by neuropeptide Y in hypertensive situations, the paraventricular nucleus of spontaneously hypertensive rats was exposed to neuropeptide Y (10(-9) M), and levels of norepinephrine were sampled by microdialysis. Norepinephrine levels in spontaneously hypertensive rats were significantly increased and did not change after exposure to neuropeptide Y, in sharp contrast to the decreases seen in Wistar-Kyoto controls. To ascertain whether these alterations in norepinephrine control were specific to the model used, a similar series of experiments was carried out in the paraventricular nucleus of aortic-banded rats. These studies supported the previous findings. Norepinephrine levels in aortic-banded rats were markedly elevated when compared with sham-operated controls and demonstrated no change after exposure to neuropeptide Y, whereas decreases of > 50% were seen in sham-operated controls. These results support the view that mechanisms normally involving neuropeptide Y as a neuromodulator in the paraventricular nucleus are altered in hypertensive situations. It is suggested that hypertension may precipitate changes in mechanisms involving brain neuropeptide Y and increased sympathetic activity.

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