Interaction between myocardial depressant factor and vasoactive mediators with ischemia and shock

1987 ◽  
Vol 252 (2) ◽  
pp. R193-R205 ◽  
Author(s):  
A. M. Lefer

A variety of endogenously formed vasoconstrictor substances circulate in the blood and act as mediators in ischemia and shock states. These humoral substances are chemically diverse and include peptides, lipids, and aromatic amines. One of the novel peptides, myocardial depressant factor (MDF) and several interesting lipids, including thromboxane A2 (TxA2), leukotriene D4 (LTD4), and platelet-activating factor (PAF) are very potent substances having a broad profile of pathophysiological actions. Some of the effects of MDF include myocardial depression, constriction of splanchnic vessels, and impairment of phagocytosis. TxA2 primarily constricts blood vessels, aggregates platelets, and increases membrane permeability. LTD4 is a potent vasoconstrictor and bronchoconstrictor and promotes leakage of fluid out of blood vessels. PAF activates platelets, depresses cardiac function, constricts airways, and enhances fluid leakage from the intravascular compartment. Thus vasoconstriction is common to all these mediators. Moreover, these vasoactive substances have common mechanisms of release and interact to exacerbate ischemia and contribute to the pathogenesis of a variety of shock states. New pharmacological approaches to blocking the formation and action of these mediators have provided interesting insights into the pathophysiology of shock.

1990 ◽  
Vol 64 (01) ◽  
pp. 091-096 ◽  
Author(s):  
W J Janssens ◽  
F J S Cools ◽  
L A M Hoskens ◽  
J M Van Nueten

SummaryRidogrel (6.3 × 10−6 to 10−4 M) inhibited contractions of isolated rat caudal arteries and rabbit femoral arteries caused by U-46619. The slope of an Arunlakshana-Schild plot (pA2-value: 3.4 × 10−6 M) on the caudal artery was slightly higher than one (1.14). This effect was maximal within}D min of incubation of the blood vessel with the compound and easily reversible. Ridogrel antagonised contractions of isolated rabbit femoral arteries caused by prostaglandin Fzo2α in the same concentration range. Ridogrel also inhibited contractions induced by aggregating rat platelets on isolated rat caudal arteries (itt the presence of ketanserin 4 × 10−7 M) and on isolated rabbit pulmonary and femoral arteries (in the absence of ketanserin). Ridogrel had no effect on Ca2+-induced contractions in depolarised isolated rabbit femoral arteries, and at 10−4 M antagonised serotonin-induced contractions in this blood vessel. Its effect on serotonin-induced contractions was statistically significant but very small on isolated rat caudal arteries. These observations indicate that ridogrel is an antagonist of prostaglandin endoperoxide/thromboxane A2 and prostaglandin F2α raCeptors on vascular smooth muscle.


1985 ◽  
Vol 249 (3) ◽  
pp. H698-H702 ◽  
Author(s):  
D. Ezra ◽  
G. Feuerstein ◽  
J. F. Czaja ◽  
F. R. Laurindo ◽  
C. K. Finton ◽  
...  

Coronary blood flow (CBF) and myocardial contractility decrease markedly in response to intracoronary administration of leukotriene D4 (LTD4). With steady infusion, however, both CBF and contractility escape, approaching preinfusion values despite ongoing LTD4 administration. To clarify the mechanism of this escape, we reinfused plasma from the coronary vein draining the myocardial area receiving LTD4. Introducing this plasma into a coronary artery caused a marked rise in coronary flow for the duration of the plasma infusion. Coronary flow reduction with vasopressin or mechanical occlusion matching that caused by LTD4 failed to elicit vasodilator production. Thus a unique coronary vasodilator factor is induced by LTD4. Whole blood or platelet-rich plasma incubated with LTD4 in vitro produced the same pattern of coronary dilation on intracoronary infusion; LTD4 incubation with platelet-poor plasma failed to elicit a vasodilation. The vasodilator factor is stable and is not potassium, a prostaglandin, catecholamine, histamine, serotonin, adenosine, adenosine diphosphate, or platelet-activating factor. Production of this leukotriene-induced vasodilator factor may account for the escape from LTD4-induced coronary constriction.


2006 ◽  
Vol 54 (5) ◽  
pp. 603-610 ◽  
Author(s):  
Yoshinori Okamoto ◽  
Masaki Yokota ◽  
Soichiro Kawazoe ◽  
Hirokazu Kubota ◽  
Hitoshi Nagaoka ◽  
...  

Hypertension ◽  
2017 ◽  
Vol 70 (suppl_1) ◽  
Author(s):  
Alexandria M Betz ◽  
Gary L Pierce ◽  
Donna A Santillan ◽  
Eric J Devor ◽  
Sabrina M Scroggins ◽  
...  

Preeclampsia (PE) is characterized by late pregnancy hypertension and proteinuria. PE causes significant morbidity for the maternal-fetal unit. Circulating endothelin-1 (ET-1), a potent vasoconstrictor, is elevated at the time of diagnosis of human PE. In addition, women with PE demonstrate arterial stiffness as early as the end of the first trimester. However, it is unknown if arterial stiffness is associated with a first trimester elevation in ET-1 and post-delivery placental ET-1. We hypothesized that 1) first trimester plasma ET-1 is elevated and is associated with arterial stiffness in women who develop PE; 2) first trimester ET-1 is predictive of PE; and 3) placental ET-1 is increased in PE. To address these questions, we performed a nested case-control study in women at risk for PE. First trimester plasma ET-1 was measured via ELISA; aortic stiffness and carotid beta-stiffness (CβS) were measured by carotid-femoral pulse-wave velocity (CFPWV) and carotid tonometry/ultrasound, respectively. While the maternal age of controls (n=126; age 30 ± 0.45 years) and PE (n=15; age 31 ± 1.3 years) were similar, the PE group had a higher first trimester BMI (35 ± 3 vs. 29 ± 1 kg/m 2 , p = 0.01), systolic (125 ± 2 vs. 113 ± 1 mmHg, p< 0.01) and diastolic blood pressure (68 ± 2 vs. 60 ± 1 mmHg, p< 0.01) compared with controls. In addition, first trimester plasma ET-1 (2.7 ± 0.4 vs. 2.0 ± 0.2 pg/mL, p < 0.01), CFPWV (7.2 ± 0.5 vs. 6.1 ± 0.2 m/s, p = 0.016), and CβS (8.4 ± 1.9 vs. 6.3 ± 0.3, p = 0.055) were higher in the PE group. Consistent with previous studies, third trimester plasma ET-1 was elevated in the PE group (2.9 ± 1.1 vs. 1.6 ± 0.1 pg/mL, p < 0.01) which paralleled a 2.5 fold increase in placental decidual ET-1 mRNA (p < 0.0001). ROC analyses showed that first trimester plasma ET-1 (AUC=0.71, p < 0.001) and CFPWV (AUC=0.70, p=0.014) were predictive of PE. This study supports the novel concept that elevated ET-1 in preeclampsia begins early in the first trimester and is associated with premature arterial stiffness. Further, these novel data suggest that ET-1 may play an important role in the first trimester prediction and pathogenesis of preeclampsia.


1995 ◽  
Vol 268 (6) ◽  
pp. H2260-H2266
Author(s):  
N. P. Curzen ◽  
M. J. Griffiths ◽  
T. W. Evans

Sepsis is characterized by hyporesponsiveness of vascular smooth muscle to pressor agents. Levels of the potent vasoconstrictor, endothelin-1 (ET-1), are elevated in animal models of sepsis and in patients. This study assesses the contractile response of pulmonary artery from endotoxin-pretreated rats to ET-1 to determine whether this contraction is modified by the endothelium. Both intact and denuded rings from endotoxin-pretreated rats exhibited hyporesponsiveness to ET-1, but the endothelium was found to be essential for maximal ET-1-induced contraction. Upon pretreatment of vessels with the cyclooxygenase inhibitor, indomethacin (10(-5) M), the novel ETB-receptor antagonist, BQ-788 (10(-8) and 10(-6) M), and the thromboxane A2-receptor antagonist, ICI-192605 (10(-5) M), each of these agents caused a reduction in the ET-1-induced contraction of endotoxin-pretreated rat pulmonary artery only in the presence of the endothelium but had no effect in endothelium-denuded vessels or in sham-treated groups. These findings demonstrate that ET-1-induced contraction in pulmonary arteries from septic rats is partially dependent upon an endothelially derived cyclooxygenase product, the release of which appears to involve ETB-receptor stimulation.


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