Search results for "Constriction"
showing 10 items of 254 documents
Heterogeneity of P2-Purinoceptors in Brain Circulation
1990
The existence of P2-purinoceptors in the cerebrovascular bed was examined by testing the effects of ATP and its stable analog, α,β-methylene-ATP, on CBF in the unanesthetized goat as well as on isometric tension in isolated goat middle cerebral artery. When injected directly into the cerebral circulation, ATP increased and α,β-methylene-ATP decreased CBF. Indomethacin did not modify either of these effects. The vasoconstrictor action of α,β-methylene-ATP was reduced by nicardipine. “In vitro,” both ATP and α,β-methylene-ATP contracted the cerebral arteries at resting tone, but the analog was more potent than ATP. Repeated application of α,β-methylene-ATP as well as indomethacin significant…
A Proposed Methodology to Control Body Temperature in Patients at Risk of Hypothermia by means of Active Rewarming Systems
2014
Hypothermia is a common complication in patients undergoing surgery under general anesthesia. It has been noted that, during the first hour of surgery, the patient’s internal temperature (Tcore) decreases by 0.5–1.5°C due to the vasodilatory effect of anesthetic gases, which affect the body’s thermoregulatory system by inhibiting vasoconstriction. Thus a continuous check on patient temperature must be carried out. The currently most used methods to avoid hypothermia are based on passive systems (such as blankets reducing body heat loss) and on active ones (thermal blankets, electric or hot-water mattresses, forced hot air, warming lamps, etc.). Within a broader research upon the environment…
C-reactive protein and efficacy of antiplatelet therapy in (intracranial) atherosclerosis
2018
C-reactive protein (CRP) and other inflammatory biomarkers can indicate both the severity and extent of atherosclerosis, reflecting the inflammatory nature of the disease process.1 Atherogenesis begins with an inflammatory response to vascular injury with cells and mediators initiating the healing response and later inducing growth of atherosclerotic plaques. Inflammation then increases plaque instability, promoting rupture, fissuring, or erosion—the pathogenetic milieu of thrombosis in atherothrombotic ischemic strokes.
Role of JAK2/STAT3 pathway in vascular function of pulmonary fibrosis patients
2015
Background: Idiopathic Pulmonary Fibrosis (IPF) is a chronic progressive lung disease with a life expectancy of 2-5 years. A proportion of IPF patients develop pulmonary hypertension (PH), characterized by vasoconstriction and remodeling of pulmonary arteries. Currently, no therapy can improve survival of patients diagnosed with this disease. JAK2/STAT3 molecular route is overexpressed in proliferative disorders, however, its role in PH- associated IPF is unknown. Objective: To analyze the role of JAK2/STAT3 in vascular function of IPF patients with PH. We hypothesized that inhibition of JAK2, STAT3 or JAK2/STAT3 may improve vascular function. Methods: Human precision cut lung slices and ar…
Effects of inhaled corticosteroids, leukotriene receptor antagonists, or both, plus long-acting beta2-agonists on asthma pathophysiology: a review of…
2004
Chronic inflammation and smooth muscle dysfunction are consistent features of asthma, and are responsible for disease progression and airway remodelling. The development of chronic airway inflammation depends upon the recruitment and activation of inflammatory cells and the subsequent release of inflammatory mediators, including cytokines. Cellular and histological evaluation of drugs with anti-inflammatory activity, such as inhaled corticosteroids (ICSs), is achieved by analysing samples of lung tissue or biological fluids, obtained by techniques such as bronchial biopsy, bronchoalveolar lavage and sputum induction. These provide valuable information on the inflammatory processes occurring…
Activation of soluble guanylyl cyclase by YC-1 in aortic smooth muscle but not in ventricular myocardium from rat
1997
1 The effects of YC-1 (3-(5′-hydroxymethyl-2′-furyl)-1-benzyl indazole), an activator of soluble guanylyl cyclase, on tension, levels of cyclic GMP and cyclic AMP, and cardiac L-type Ca2+-current (ICa(L)) were investigated in aortic smooth muscle and ventricular heart muscle from rat. 2 YC-1 (0.1–30 μM) induced a concentration-dependent relaxation in aortic rings precontracted with phenylephrine (3 μM). The relaxant effects of YC-1 were reversed by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (30 μM; ODQ), potentiated by zaprinast (10 μM) and antagonized by Rp-8-Br-cGMPS (100 μM). 3 In ventricular heart muscle strips, YC-1 (30 μM) exhibited no effects on force of contraction (Fc) in the abse…
The α1B-adrenoceptor subtype mediates adrenergic vasoconstriction in mouse retinal arterioles with damaged endothelium
2014
Background and Purpose The α1-adrenoceptor family plays a critical role in regulating ocular perfusion by mediating responses to catecholamines. The purpose of the present study was to determine the contribution of individual α1-adrenoceptor subtypes to adrenergic vasoconstriction of retinal arterioles using gene-targeted mice deficient in one of the three adrenoceptor subtypes (α1A-AR−/−, α1B-AR−/− and α1D-AR−/− respectively). Experimental Approach Using real-time PCR, mRNA expression for individual α1-adrenoceptor subtypes was determined in murine retinal arterioles. To assess the functional relevance of the three α1-adrenoceptor subtypes for mediating vascular responses, retinal vascular…
Increased endothelin-1 vasoconstriction in mesenteric resistance arteries after superior mesenteric ischaemia-reperfusion
2012
BACKGROUND AND PURPOSE Endothelin-1 (ET-1) plays an important role in the maintenance of vascular tone. We aimed to evaluate the influence of superior mesenteric artery (SMA) ischaemia-reperfusion (I/R) on mesenteric resistance artery vasomotor function and the mechanism involved in the changes in vascular responses to ET-1. EXPERIMENTAL APPROACH SMA from male Sprague-Dawley rats was occluded (90 min) and following reperfusion (24 h), mesenteric resistance arteries were dissected. Vascular reactivity was studied using wire myography. Protein and mRNA expression, superoxide anion (O2•−) production and ET-1 plasma concentration were evaluated by immunofluorescence, real-time quantitative PCR,…
Pathological role of a constitutively active population of α1D -adrenoceptors in arteries of spontaneously hypertensive rats
2002
The role of a constitutively active population of α1D-adrenoceptors was analysed in arteries obtained from spontaneously hypertensive rats (SHR) and controls (WKY) divided into three groups: young prehypertensive, adult hypertensive, and adult animals chronically treated with captopril (50 mg kg−1 per day orally) in order to prevent the hypertensive state. In adult SHR, a significant increase in BMY 7378 potency (not in prazosin potency) was observed in aorta, mesenteric artery, and the first and second branches of the small mesenteric arteries with respect to WKY rats. This difference was not observed in iliac and tail arteries, which suggests an increased functional role of α1D-adrenocept…
Explaining the phenomenon of nitrate tolerance.
2005
During the last century, nitroglycerin has been the most commonly used antiischemic and antianginal agent. Unfortunately, after continuous application, its therapeutic efficacy rapidly vanishes. Neurohormonal activation of vasoconstrictor signals and intravascular volume expansion constitute early counter-regulatory responses (pseudotolerance), whereas long-term treatment induces intrinsic vascular changes, eg, a loss of nitrovasodilator-responsiveness (vascular tolerance). This is caused by increased vascular superoxide production and a supersensitivity to vasoconstrictors secondary to a tonic activation of protein kinase C. NADPH oxidase(s) and uncoupled endothelial nitric oxide synthase …