Interaction between pregnancy-induced bioactive peptides and the placental proteases

1995 ◽  
Vol 7 (6) ◽  
pp. 1431 ◽  
Author(s):  
S Mizutani ◽  
K Goto ◽  
K Mizuno ◽  
A Itakura ◽  
O Kurauchi ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Umbilical Artery ◽  
Bioactive Peptides ◽  
Diastolic Pressure ◽  
Peptide Hormones ◽  
Maternal Serum ◽  
Doppler Technique ◽  
Vasoactive Peptides ◽  
Pressor Responses

Studies have shown that placental proteases metabolize vasoactive peptides, possibly derived from the fetus, and protect the exchange of peptide hormones across the placenta in order to maintain feto-placental homeostasis. Changes in maternal serum protease activities were useful for monitoring pre-eclampsia and predicting the onset of labour. The study showed that possible role of oxytocinase in the maintenance of gestation and the possible involvement of angiotensinase in the attenuated pressor responses to angiotensin II during pregnancy, respectively. In addition, the ratio of peak systolic over least diastolic pressure (S/D) of uterine or umbilical artery assessed by the Doppler technique was closely correlated with the concentrations of maternal serum proteases in pre-eclampsia, which suggested that placental proteases might control utero-placental circulation via the regulation of concentrations of vasoactive peptides in uteroplacental circulation.

scholarly journals Pressor responses to norepinephrine in rabbits with 3-day and 30-day renal artery stenosis. The role of angiotensin II.

1978 ◽  
Vol 43 (3) ◽  
pp. 437-446 ◽  
Author(s):  
S Ichikawa ◽  
J A Johnson ◽  
W L Fowler ◽  
C G Payne ◽  
K Kurz ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Renal Artery ◽  
Renal Artery Stenosis ◽  
Artery Stenosis ◽  
Pressor Responses

The Role of Endogenous Opiates in the Area Postrema Pressor Pathway

1980 ◽  
Vol 59 (s6) ◽  
pp. 267s-269s ◽  
Author(s):  
Julianna E. Szilagyi ◽  
C. M. Ferrario
Keyword(s):  
Angiotensin Ii ◽  
Vertebral Artery ◽  
Area Postrema ◽  
Pressor Response ◽  
Cardiovascular Effects ◽  
Endogenous Opiates ◽  
Pressor Responses ◽  
Vasomotor Activity ◽  
The Brain

1. Intra-vertebral artery-administered angiotensin II acts at the area postrema to facilitate central sympathetic vasomotor activity. Recent evidence suggests a possible role of the opiate system in the mechanism of action of angiotensin II at the level of the brain stem. 2. In these experiments, we show that the morphine antagonist naloxone reduces significantly the magnitude of the pressor response to vertebral artery-infused angiotensin II. 3. Morphine, in contrast, doubled the peak of the vertebral response to identical doses of the peptide. Neither naloxone nor morphine affected the pressor responses to intravenously administered angiotensin II. 4. The data suggest that the endogenous opiate system in the medulla modulates the cardiovascular effects of angiotensin II at the level of the area postrema.

scholarly journals Changes of renal AQP2, ENaC, and NHE3 in experimentally induced heart failure: response to angiotensin II AT1 receptor blockade

2009 ◽  
Vol 297 (6) ◽  
pp. F1678-F1688 ◽  
Author(s):  
Sophie C. Lütken ◽  
Soo Wan Kim ◽  
Thomas Jonassen ◽  
David Marples ◽  
Mark A. Knepper ◽  
...  
Keyword(s):  
Heart Failure ◽  
Angiotensin Ii ◽  
Diastolic Pressure ◽  
Collecting Duct ◽  
Left Ventricular ◽  
Outer Medulla ◽  
Outer Stripe ◽  
Medullary Collecting Duct ◽  
Type 3

Heart failure (HF) was induced by ligation of the left anterior descending artery (LAD). Left ventricular end-diastolic pressure (LVEDP) >25 mmHg (at day 23 after LAD ligation) was the inclusion criterion. The rats were divided into three groups: sham-operated (Sham, n = 23, LVEDP: 5.6 ± 0.6 mmHg), HF ( n = 14, LVEDP: 29.4 ± 1.4 mmHg), and candesartan (1 mg·kg−1·day−1 sc)-treated HF (HF + Can, n = 9, LVEDP: 29.2 ± 1.2 mmHg). After 7 days (i.e., 29 days after LAD ligation) semiquantitative immunoblotting revealed increased abundance of inner medulla aquaporin-2 (AQP2) and AQP2 phosphorylated at Ser256 (p-AQP2) in HF. There was also markedly enhanced apical targeting of AQP2 and p-AQP2 in inner medullary collecting duct (IMCD) in HF compared with Sham rats, shown by immunocytochemistry. Candesartan treatment significantly reversed the increases in both AQP2 and p-AQP2 expression and targeting. In contrast, there were only modest changes in other collecting duct segments. Semiquantitative immunoblots revealed increased expression of type 3 Na+/H+ exchanger (NHE3) and Na+-K+-2Cl− cotransporter (NKCC2) in kidneys from HF compared with Sham rats: both effects were reversed or prevented by candesartan treatment. The protein abundance of α-epithelial sodium channel (α-ENaC) was increased while β-ENaC and γ-ENaC expression was decreased in the cortex and outer stripe of the outer medulla in HF compared with Sham rats, which was partially reversed by candesartan treatment. These findings strongly support an important role of angiotensin II in the pathophysiology of renal water and sodium retention associated with HF.

scholarly journals The role of brain angiotensin II in the mechanism of the pressor responses to intracisternal injection of hypertonic NaCl in urethane anesthetized rats.

1982 ◽  
Vol 46 (5) ◽  
pp. 534-539 ◽  
Author(s):  
KAZUO TAKEDA ◽  
HAKUO TAKAHASHI ◽  
HIROSHI ASHIZAWA ◽  
ATSUSHI INOUE ◽  
RIEKO SHIKUMA ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Anesthetized Rats ◽  
Pressor Responses ◽  
Intracisternal Injection

scholarly journals Role of Endothelin and Isoprostanes in Slow Pressor Responses to Angiotensin II

Hypertension ◽  
2001 ◽  
Vol 37 (2) ◽  
pp. 505-510 ◽  
Author(s):  
Maria Clara Ortiz ◽  
Elisabeth Sanabria ◽  
Melissa C. Manriquez ◽  
Juan C. Romero ◽  
Luis A. Juncos
Keyword(s):  
Angiotensin Ii ◽  
Pressor Responses

Abstract P118: Angiotensin Ii Hypertension-dependent Decrease In Circadian Rhythms Of Cardiovascular Parameters: Role Of Peroxisome Proliferator Activated Receptor-α

Hypertension ◽  
2021 ◽  
Vol 78 (Suppl_1) ◽  
Author(s):  
Dexter L Lee ◽  
Sheree M Johnson ◽  
Ian Stukes ◽  
Nia Williams ◽  
Ugoeze C Ananaba ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Circadian Rhythms ◽  
Diastolic Pressure ◽  
Interleukin 17 ◽  
Peroxisome Proliferator ◽  
Ang Ii ◽  
Peroxisome Proliferator Activated Receptor ◽  
Cardiovascular Parameters ◽  
Nitrite Nitrate

Decreases in circadian rhythms of cardiovascular parameters, such as day to night changes in mean arterial pressure (MAP), heart rate (HR), pulse pressure (PP), systolic (SP) and diastolic pressure (DP) are an index of cardiovascular disease. Peroxisome proliferator activated receptor - alpha (PPAR-α) has been shown to decrease inflammatory markers and hypertension a slow pressor dose of Angiotensin II (Ang II); however, the role of PPAR-α on cardiovascular parameters during the initial stages of Ang II infusion is unknown. We hypothesize that the absence of PPAR-α will cause a reduction in the day to night changes in MAP, HR, PP, SP and DP during the initial stages of a slow pressor dose of Ang II. Male (10 - 12 weeks old) PPAR-αknockout (KO) and wild-type (WT) mice were infused with Ang II (400 ng/kg/min) for three days. Radiotelemetry was used to measure the cardiovascular parameters. The baseline MAP values were: 100 + 10 mmHg (WT) and 108 + 9 mmHg for KO. The baseline HR values were: 530 + 10 bpm (WT) and 526 + 6 bpm (KO). The baseline PPs were 17 + 0.2 mmHg (WT) and 18 + 0.3 mmHg (KO). The baseline SBPs were 108 + 9 mmHg (WT) and 116 + 10 mmHg (KO). The baseline DBPs were 91 + 9 mmHg (WT) and 98 + 10 mmHg (KO). During the first three days of Ang II infusion, the change in day to night MAP was 20 ± 2 mmHg and 10 ± 2 mmHg in Ang II treated WT and KO mice, respectively. Changes in day to night HR were 25 ± 4 bpm and 46 ± 7 bpm for WT and KO mice, respectively. The day to night changes in PP were 8 ± 1 mmHg for WT and 2 ± 2 mmHg for KO mice. The day to night changes in SBPs were 20 ± 2 mmHg and 12 ± 3 mmHg for WT and KO mice, respectively. Changes in day to night DBPs were 18 ± 2 mmHg for WT and 9 ± 2 mmHg for KO mice. TBARS and Interleukin-17 were increased in heart homogenates of KO + Ang II (15 ± 2 μM) and (1.5 ± 0.3 ng/mL) vs WT + Ang II (11 ± 3 μM) and (1.0 ± 0.2 ng/mL). Nitrite/Nitrate was decreased in KO + Ang II (1.0 ± 0.1 nM) vs WT + Ang II (1.5 ± 0.5 nM). In summary, the absence of PPAR-α decreases the day to night changes in MAP, SBP, DBP and PP during the initial three days of a slow pressor dose of Ang II. In the absence of PPAR-α, increases in oxidative stress and inflammation are mechanisms that may contribute to the changes in the cardiovascular parameters and suggest the occurrence of cardiovascular diseases during a slow pressor dose of Ang II-infusion.

Nitric oxide generation and hypoxic vasoconstriction in buffer-perfused rabbit lungs

1995 ◽  
Vol 78 (4) ◽  
pp. 1509-1515 ◽  
Author(s):  
F. Grimminger ◽  
R. Spriestersbach ◽  
N. Weissmann ◽  
D. Walmrath ◽  
W. Seeger
Keyword(s):  
Nitric Oxide ◽  
Angiotensin Ii ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Sharp Drop ◽  
Pulmonary Vasoconstriction ◽  
Exhaled No ◽  
Pressor Responses ◽  
Hypoxic Vasoconstriction ◽  
Alveolar Hypoxia

Nitric oxide generation and hypoxic vasoconstriction in buffer-perfused rabbit lungs. J. Appl. Physiol. 78(4): 1509–1515, 1995.--We investigated the role of nitric oxide (NO) generation in hypoxic pulmonary vasoconstriction in buffer-perfused rabbit lungs. Exhaled NO was detected by chemiluminescence, and intravascular NO release was quantified as perfusate accumulation of nitrite, peroxynitrite, and nitrate (NOx). Under baseline conditions, exhaled NO was 45.3 +/- 4.1 parts per billion (1.8 +/- 0.2 nmol/min), and lung NOx release into the perfusate was 4.1 +/- 0.4 nmol/min. Alveolar hypoxia (alveolar PO2 of approximately 23 Torr) induced readily reproducible pressor responses preceded by a sharp drop in exhaled NO concentration. In contrast, perfusate NOx accumulation was not affected. Vasoconstrictor responses to U-46619 and angiotensin II were not accompanied by a decrease in NO exhalation. NG-monomethyl-L-arginine dose-dependently suppressed NO exhalation and amplified pressor responses to hypoxia > U-46619 and angiotensin II. In conclusion, portions of baseline NO generation originating from sites with ready access to the gaseous space sharply decrease in response to alveolar hypoxia, whereas the intravascular release of NO is unchanged. Such differential regulation of lung NO synthesis in response to hypoxia may suggest a complex role in the regulation or modulation of hypoxic pulmonary vasoconstriction.

scholarly journals Role of AT1 receptors and autonomic nervous system in mediating acute pressor responses to ANG II in anesthetized mice

1999 ◽  
Vol 277 (5) ◽  
pp. E838-E847 ◽  
Author(s):  
Trinity J. Bivalacqua ◽  
Ajay Dalal ◽  
Hunter C. Champion ◽  
Philip J. Kadowitz
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Angiotensin Ii ◽  
Peripheral Resistance ◽  
Inhibitory Effects ◽  
Hemodynamic Responses ◽  
Autonomic Nervous ◽  
Pressor Responses ◽  
Cd1 Mice

Hemodynamic responses to angiotensin II and the role of AT1 and AT2 receptors and the autonomic nervous system in mediating acute responses to angiotensin II were investigated in anesthetized CD1 mice. Injections of angiotensin II caused dose-related increases in systemic arterial pressure that were antagonized by candesartan. Pressor responses to angiotensin II were not altered by PD-123,319 in doses up to 25 mg/kg iv. At the lowest dose studied (20 μg/kg iv), the inhibitory effects of candesartan were competitive, whereas at the highest dose (100 μg/kg iv) the dose-response curve for angiotensin II was shifted to the right in a nonparallel manner with inhibitory effects that could not be surmounted. The inhibitory effects of candesartan were selective and were similar in animals pretreated with enalaprilat (1 mg/kg iv) to reduce endogenous angiotensin II production. Acute pressor responses to angiotensin II were not altered by propranolol (200 μg/kg iv), phentolamine (200 μg/kg iv), or atropine (1 mg/kg iv) but were enhanced by hexamethonium (5 mg/kg iv). Increases in total peripheral resistance induced by angiotensin II were inhibited by the AT1-receptor antagonist but were not altered by AT2-, α-, or β-receptor antagonists. These results suggest that acute pressor responses to angiotensin II are mediated by AT1 receptors, are buffered by the baroreceptors, and are not modulated by effects on AT2 receptors and that activation of the sympathetic nervous system plays little if any role in mediating rapid hemodynamic responses to the peptide in anesthetized CD1 mice.

Effects of angiotensin II on cultured rat renomedullary interstitial cells are mediated by AT1A receptors

1996 ◽  
Vol 271 (5) ◽  
pp. F1020-F1028 ◽  
Author(s):  
C. Maric ◽  
G. P. Aldred ◽  
A. M. Antoine ◽  
R. G. Dean ◽  
E. Eitle ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Angiotensin Ii ◽  
Interstitial Cells ◽  
Receptor Subtype ◽  
Ang Ii ◽  
Sprague Dawley ◽  
Vasoactive Peptides ◽  
Polymerase Chain ◽  
Second Messenger Pathways

Renomedullary interstitial cells (RMICs) are prominent in the inner medullary interstitium and have binding sites for several vasoactive agents, including angiotensin II (ANG II). Although the functional role of RMICs remains largely unknown, it is likely that the interaction between RMICs and vasoactive peptides is important in the regulation of renal function. The current investigation characterizes the cellular responses following treatment of RMICs with ANG II. Studies were performed on RMICs isolated from Sprague-Dawley rat kidneys. 125I-labeled [Sar1,Ile8]ANG II specifically bound to RMICs at sites determined by reverse transcription-polymerase chain reaction to be of the AT1A subtype. ANG II (10(-6) and 10(-10) M) had no effect on either basal or forskolin-stimulated adenosine 3',5'-cyclic monophosphate accumulation in RMICs but increased intracellular inositol 1,4,5-trisphosphate concentration after 10 s and intracellular calcium concentration after 18 s. For RMICs plated at low densities, ANG II (10(-6) M) induced an increase in [3H]thymidine incorporation, mediated through the AT1-receptor subtype. For RMICs plated at high densities, ANG II (10(-6) M) induced an increase in extracellular matrix synthesis as detected by trans-35S incorporation, an effect also mediated by AT1 receptors. We conclude that ANG II AT1A receptors on cultured RMICs are coupled to intracellular second messenger pathways leading to hyperplasia and synthesis of extracellular matrix.

Role of angiotensin II type 1 receptors in the subfornical organ in the pressor responses to central sodium in rats

2013 ◽  
Vol 1527 ◽  
pp. 79-86 ◽  
Author(s):  
Missale A. Tiruneh ◽  
Bing S. Huang ◽  
Frans H.H. Leenen
Keyword(s):  
Angiotensin Ii ◽  
Subfornical Organ ◽  
Pressor Responses
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