Regional contractile responses in pulmonary artery to α- and β-adrenoceptor agonists

1987 ◽  
Vol 65 (6) ◽  
pp. 1165-1170 ◽  
Author(s):  
Ralph C. Kolbeck ◽  
William A. Speir Jr.

Contractile sensitivity and reactivity to α- and β-adrenoceptor stimulation was studied in incubated rabbit pulmonary artery cylindrical segments of differing diameters. Distinct differences were noted between the responses of extra- and intra-pulmonary pulmonary arteries to norepinephrine and isoproterenol. The sensitivity to norepinephrine was largest in the intrapulmonary pulmonary arteries. Arterial reactivity to norepinephrine was greatest in the larger of the intrapulmonary vessel segments, diminishing considerably as the vessels became smaller. Cocaine did not cause substantial alterations in the response of any of the arterial segments to the α-agonist. Phentolamine, however, exerted its influence primarily in the smaller arterial segments. Vascular sensitivity to isoproterenol was least in the intrapulmonary pulmonary arteries. These smaller vessel segments, however, were more reactive to isoproterenol than were the extrapulmonary pulmonary arterial segments. Propranolol, at a concentration of 10−8 M, was an effective antagonist of the β-agonist; at a concentration of 10−7 M, however, this antagonist was related to isoproterenol-induced arterial contraction, apparently by stimulation of α-receptor sites. The results of this study demonstrated a regional heterogeneity in the contractile response of the pulmonary artery to α- and β-stimulation. The extrapulmonary arterial segments were found to be more sensitive to β-stimulation than were the smaller, intrapulmonary, segments. The intrapulmonary arterial segments, on the other hand, were found to be more sensitive to α-stimulation than were the extrapulmonary segments.

VASA ◽  
2018 ◽  
Vol 47 (5) ◽  
pp. 361-375 ◽  
Author(s):  
Harold Goerne ◽  
Abhishek Chaturvedi ◽  
Sasan Partovi ◽  
Prabhakar Rajiah

Abstract. Although pulmonary embolism is the most common abnormality of the pulmonary artery, there is a broad spectrum of other congenital and acquired pulmonary arterial abnormalities. Multiple imaging modalities are now available to evaluate these abnormalities of the pulmonary arteries. CT and MRI are the most commonly used cross-sectional imaging modalities that provide comprehensive information on several aspects of these abnormalities, including morphology, function, risk-stratification and therapy-monitoring. In this article, we review the role of state-of-the-art pulmonary arterial imaging in the evaluation of non-thromboembolic disorders of pulmonary artery.


2011 ◽  
Vol 110 (1) ◽  
pp. 188-198 ◽  
Author(s):  
Rebecca R. Vanderpool ◽  
Ah Ram Kim ◽  
Robert Molthen ◽  
Naomi C. Chesler

Hypoxic pulmonary hypertension (HPH) is initially a disease of the small pulmonary arteries. Its severity is usually quantified by pulmonary vascular resistance (PVR). Acute Rho kinase inhibition has been found to reduce PVR toward control values in animal models, suggesting that persistent pulmonary vasoconstriction is the dominant mechanism for increased PVR. However, HPH may also cause proximal arterial changes, which are relevant to right ventricular (RV) afterload. RV afterload can be quantified by pulmonary vascular impedance, which is obtained via spectral analysis of pulsatile pressure-flow relationships. To determine the effects of HPH independent of persistent pulmonary vasoconstriction in proximal and distal arteries, we quantified pulsatile pressure-flow relationships before and after acute Rho kinase inhibition and measured pulmonary arterial structure with microcomputed tomography. In control lungs, Rho kinase inhibition decreased 0 Hz impedance (Z0), which is equivalent to PVR, from 2.1 ± 0.4 to 1.5 ± 0.2 mmHg·min·ml−1 ( P < 0.05) and tended to increase characteristic impedance (ZC) from 0.21 ± 0.01 to 0.22 ± 0.01 mmHg·min·ml−1. In HPH lungs, Rho kinase inhibition decreased Z0 ( P < 0.05) without affecting ZC. Microcomputed tomography measurements performed on lungs after acute Rho kinase inhibition demonstrated that HPH significantly decreased the unstressed diameter of the main pulmonary artery (760 ± 60 vs. 650 ± 80 μm; P < 0.05), decreased right pulmonary artery compliance, and reduced the frequency of arteries of diameter 50–100 μm (both P < 0.05). These results demonstrate that acute Rho kinase inhibition reverses many but not all HPH-induced changes in distal pulmonary arteries but does not affect HPH-induced changes in the conduit arteries that impact RV afterload.


Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Kenzo Ichimura ◽  
Tetsuya Matoba ◽  
Ryoji Nagahama ◽  
Kaku Nakano ◽  
Kenji Sunagawa ◽  
...  

Background: Pulmonary arterial hypertension (PAH) is an intractable disease of small pulmonary artery in which multiple pathogenetic factors are involved. We have previously reported that poly(lactic acid/glycolic acid) (PLGA) nanoparticle (NP)-mediated targeting of pitavastatin into lungs by intratracheal instillation attenuated the development of PAH. In the present study we examined the effects of intravenous treatment with pitavastatin-NPs on the progression of already established PAH induced by monocrotaline (MCT). Methods and Results: Male Sprague-Dawley rats (200 to 230 g) were injected subcutaneously with 60 mg/kg MCT to induce PAH. At day 17 after MCT injection when PAH had been already established, animals were randomly divided into 4 groups, which treated with intravenous daily bolus administration of the following drugs for consecutive 4 days from 17 to 20 days after MCT injection; 1) vehicle, 2) FITC-NPs, 3) pitavastatin alone (1, 3, 10 or 30 mg/kg), or 4) pitavastatin-NPs (containing 1 or 3 mg/kg pitavastatin). Treatment with pitavastatin-NPs, but not with pitavastatin alone attenuated the progression of established PAH (Fig. A) associated with the reduction of inflammation and small pulmonary artery remodeling (stenosis and obstruction of pulmonary arterial branches) (Fig. B). In trace experiments, intravenous administration of FITC-NPs revealed the targeting of FITC-NPs into small pulmonary artery in rats with MCT-induced PAH, but not in normal animals. Importantly, in a separate protocol, treatment with pitavastatin-NPs improved the survival rate at day 35 (30% in pitavastatin-NP group vs. 61% in FITC-NP group, P<0.05 by Kaplan-Meier). Conclusion: A novel NP-mediated targeting of pitavastatin into small pulmonary arteries by intravenous administration attenuated the progression of established PAH and improved survival associated with anti-inflammatory and anti-remodeling effects in a rat model of MCT-induced PAH.


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.


Author(s):  
Aiping Liu ◽  
Lian Tian ◽  
Diana M. Tabima ◽  
Naomi C. Chesler

Pulmonary artery hypertension (PAH) is a female dominant disease (the female-to-male ratio is 4:1), characterized by small distal pulmonary arterial narrowing and large proximal arterial stiffening, which increase right ventricle (RV) afterload and ultimately lead to RV failure [1,2]. Our recent studies have shown that collagen accumulation induced by chronic hypoxia increases the stiffness of the large extralobar pulmonary arteries (PAs) [3], and affects pulmonary vascular impedance (PVZ) [4]. The role of collagen in the female predominance in developing PAH has not been explored to date.


1988 ◽  
Vol 65 (6) ◽  
pp. 2468-2474 ◽  
Author(s):  
Y. Hoshino ◽  
H. Obara ◽  
M. Kusunoki ◽  
Y. Fujii ◽  
S. Iwai

The mechanism for hypoxic pulmonary vasoconstriction (HPVC) was investigated in human pulmonary arterial strips. Hypoxia in the presence of histamine (10(-6) M) caused marked pulmonary arterial contraction, which was reversed by O2. The hypoxic contraction in the presence of histamine was inhibited by diphenhydramine, but not by cimetidine. The hypoxic histamine-mediated contraction was attenuated but still present in the absence of extracellular Ca2+, or by the inhibitors of voltage-dependent Ca2+ influx. However, it was inhibited significantly by a further depletion of intracellular Ca2+, or by HA 1004, an intracellular calcium antagonist. A low concentration (10(-7) M) of a calcium ionophore, A23187, enhanced the hypoxic contraction in the presence of histamine, whereas procaine completely inhibited it. W-7, a calmodulin inhibitor, significantly decreased the hypoxic histamine-mediated contraction, but 12-O-tetradecanoylphorbol-13-acetate (TPA), a C-kinase promotor, had no effect. The hypoxic contractile response was also observed in the presence of both A23187 and KCl instead of histamine, but the hypoxia-induced contraction with KCl alone was much smaller than that. These results indicate that hypoxia in the presence of certain other vasoactive agents has a potent contractile effect on the human pulmonary artery and that the response is dependent on Ca2+. Enhancement of both Ca2+ influx and Ca2+ release from intracellular storage sites by hypoxia, which interacts with calmodulin, were suggested to be involved in the mechanism of HPVC.


1963 ◽  
Vol 204 (4) ◽  
pp. 619-625 ◽  
Author(s):  
John W. Hyland ◽  
George T. Smith ◽  
Lockhart B. McGuire ◽  
Donald C. Harrison ◽  
Florence W. Haynes ◽  
...  

Pulmonary embolism was produced in 30 closed-chest 8-kg dogs with polystyrene spheres, glass beads, or blood clots of precise graded size. The sizes matched selectively the internal diameter of pulmonary arteries from lobar branches (5–6 mm) down to atrial arteries (0.17 mm). Emboli were injected into the right atrium until the pressure in the pulmonary artery rose 5–10 mm Hg. The number of emboli of a given size required to produce this incipient pulmonary hypertension was compared with the number of vessels of that same size as determined from the literature as well as by postmortem injection with Schlesinger mass. The number of emboli bore a constant relation to the number of vessels of that same size. With each size, the majority of vessels had to be occluded before pulmonary hypertension appeared. This was true even in the absence of anesthesia. The results support the thesis that mechanical blockade rather than vasoconstriction is the mechanism by which pulmonary hypertension is produced by emboli occluding pulmonary arterial (as opposed to arteriolar) vessels.


2017 ◽  
Vol 07 (02) ◽  
pp. 102-105
Author(s):  
Marina Rubinshtein ◽  
Tal Tirosh-Wagner ◽  
David Mishaly ◽  
Gili Kenet ◽  
Gideon Paret ◽  
...  

AbstractPulmonary arterial thrombosis is an extremely rare occurrence in the neonatal population. We describe a 2-week-old female neonate who presented in critical condition with severe cyanosis and dehydration and was found to have a large thrombus in the main branches of the pulmonary arteries. She was successfully treated with surgical embolectomy. Pulmonary arterial thrombosis should always be considered in the differential diagnosis of a dehydrated neonate presenting with severe cyanosis and evidence of pulmonary hypertension.


2000 ◽  
Vol 10 (4) ◽  
pp. 419-422 ◽  
Author(s):  
Astolfo Serra ◽  
Francisco Chamie ◽  
R.M. Freedom

AbstractMajor abnormalities of pulmonary circulation are uncommon in the patient with pulmonary atresia and intact ventricular septum. Non-confluent pulmonary arteries have only rarely been described in this setting. In this case report, we describe a patient in whom the pulmonary arteries are non-confluent, with the right pulmonary artery supplied through a right-sided arterial duct, and the left pulmonary artery most likely through a fifth aortic arch, thus providing a systemic-to-pulmonary arterial connection. We discuss the various forms of non-confluent pulmonary arteries in the setting of pulmonary atresia and intact ventricular septum.


2016 ◽  
Vol 9 (1) ◽  
pp. 267-272 ◽  
Author(s):  
Joseph P. Kriz ◽  
Nabil A. Munfakh ◽  
Gregory S. King ◽  
Juan O. Carden

Pulmonary artery intimal sarcomas are rare and lethal malignant tumors that typically affect larger vessels: the aorta, inferior vena cava, and pulmonary arteries. Since symptoms and imaging of pulmonary arterial intimal sarcomas mimic pulmonary thromboembolism, the differential diagnosis of a patient presenting with chest pain, dyspnea, and filling defect within the pulmonary arteries should include intimal sarcoma. Often right ventricular failure is observed due to pulmonary hypertension caused by the obstructive effect of the tumor and concomitant chronic thromboembolism. We report the case of a 72-year-old African-American male with arterial intimal sarcoma of the left and right pulmonary artery with extension through the right artery into the bronchus and right lung.


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