Search results for "Constriction"
showing 10 items of 254 documents
Comparison of the contractile effects of endothelin-1 and sarafotoxin S6b in goat isolated cerebral arteries
1992
1. The effects of endothelium-derived endothelin-1 and snake venom-derived sarafotoxin S6b, peptides with striking structural and functional similarities, were examined and compared in isolated middle cerebral arteries of goats. 2. Endothelin-1 and sarafotoxin S6b contracted cerebral arteries in a concentration-dependent manner. The potency of endothelin-1 (EC50 = 4.9 (3.9-6.2) x 10(-10) M) was about ten times higher than that of sarafotoxin S6b (EC50 = 5.5 (4.4-6.9) x 10(-9) M). The tension returned to basal values after repeated washings and contraction with endothelin-1 could be reproduced. Endothelin-1 and sarafotoxin S6b induced further contraction in arteries precontracted with prosta…
Impairment of the modulatory role of nitric oxide on the endothelin-1-elicited contraction of cerebral arteries: a pathogenetic factor in cerebral va…
1997
OBJECTIVE: Nitric oxide (NO) and endothelin-1 (ET-1) are two endothelium-derived factors probably involved in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage (SAH). Our aim was twofold, i.e., to ascertain whether endothelial and nonendothelial NO modulates the contractile response of cerebral arteries to ET-1 and to analyze whether this relationship might be impaired after experimental SAH. METHODS: Rings of middle cerebral artery from goats in the control group and from goats with SAH were set up for isometric tension recordings. SAH was induced 3 days before the experiments by infusion of 10 ml of autologous arterial blood through a catheter previously inserted into t…
LSC Abstract – Lung-derived prostacyclin (PGI) in endothelial dysfunction in db/db mice
2016
Aim: Increased risk of pulmonary hypertension and not clear response of pulmonary endothelium to diabetes were reasons to compare nitric oxide (NO) and PGI-dependent function in pulmonary and systemic circulation in diabetes type II. Methods: In fasted db mice (male, 20 weeks) we compared the function of pulmonary (isolated perfused lung-IPL) and aortic endothelium (wire myograph). It was supported by determination of nitrite(NO 2 - )/nitrate(NO 3 - ), PGI production, immunostaining (IMS) and western blot. Results: In diabetic IPL NO-dependent modulation of hypoxic pulmonary vasoconstriction was impaired but filtration coefficient increased; response to U46619 was enhanced; cumulative gener…
Comparison between Two Different Two-Stage Transperineal Approaches to Treat Urethral Strictures or Bladder Neck Contracture Associated with Severe U…
2012
Introduction.The recurrence of urethral/bladder neck stricture after multiple endoscopic procedures is a rare complication that can follow prostatic surgery and its treatment is still controversial.Material and Methods.We retrospectively analyzed our data on 17 patients, operated between September 2001 and January 2010, who presented severe urinary incontinence and urethral/bladder neck stricture after prostatic surgery and failure of at least four conservative endoscopic treatments. Six patients underwent a transperineal urethrovesical anastomosis and 11 patients a combined transperineal suprapubical (endoscopic) urethrovesical anastomosis. After six months the patients that presented comp…
TISSUE OXYGENATION AND TISSUE METABOLISM IN THE BRAIN CORTEX DURING PRONOUNCED ARTERIAL HYPOCAPNIA
1981
Publisher Summary This chapter describes the tissue oxygenation and tissue metabolism in the brain cortex during pronounced arterial hypocapnia. Acute arterial hypocapnia induced by hyperventilation leads to typical reactions in the circulation and the metabolism of the brain tissue. With a lowering of arterial CO2 tension, the cerebro-vascular resistance (CVR) increases resulting in a decrease of cerebral blood flow. The changes in CVR are a consequence of decreasing hydrogen ion and potassium ion concentrations in the perivascular space of the brain arterioles. The corresponding changes in the brain metabolism are characterized by elevated concentrations of lactate and pyruvate and an inc…
Isolated human chorionic vascular reactivity: Technical considerations for fresh preparations
1998
1. 1. Sixty chorionic vascular rings from normal term placentas were immersed in an organ bath for isometric tension recording to study (A) the contractile response to 120 mM of potassium chloride (KCI) after adjustment and equilibration to 1–5 g of passive tension; and (B) the concentration-response curve to KCI after adjustment and equilibration to the optimal passive tension. 2. 2. Adjustment to 4 g of passive tension elicited the maximal (P<0.007) and the latest (P<0.006) KCl-induced contraction among arterial rings. Venous rings showed the greatest contraction when adjusted to 3 g, but the differences were not significant except when compared to 1 g of passive tension (P<0.03). 3. 3. T…
TNF-α blockade may lead to improvement of vascular function in psoriasis patients.
2021
Psoriasis is one of the most common chronic inflammatory skin diseases and at the same time a risk factor for cardiovascular disease. Interleukin-17A (IL-17A)-mediated inflammation in psoriasis may lead to vascular dysfunction. This study aimed at investigating whether anti-inflammatory treatment by tumor necrosis factor (TNF)-α blockade alters vascular function in psoriasis patients. A total of 11 patients with psoriasis who underwent treatment with either adalimumab (n = 8) or etanercept (n = 3), 10 healthy control individuals and 14 patients with coronary artery disease (CAD) were included in this study. Treatment response was assessed using the Psoriasis Area and Severity Index (PASI) s…
Role of the M3 Muscarinic Acetylcholine Receptor Subtype in Murine Ophthalmic Arteries After Endothelial Removal
2014
We tested the hypothesis that the M3 muscarinic acetylcholine receptor subtype mediates cholinergic responses in murine ophthalmic arteries after endothelial removal.Muscarinic receptor gene expression was determined in ophthalmic arteries with intact and with removed endothelium using real-time PCR. To examine the role of the M3 receptor in mediating vascular responses, ophthalmic arteries from M3 receptor-deficient mice (M3R(-/-)) and respective wild-type controls were studied in vitro. Functional studies were performed in nonpreconstricted arteries with either intact or removed endothelium using video microscopy.In endothelium-intact ophthalmic arteries, mRNA for all five muscarinic rece…
Aestivation Motifs Explain Hypertension and Muscle Catabolism in Experimental Chronic Renal Failure
2020
Chronic renal failure leads to muscle mass loss and hypertension, which according to textbook teaching occur secondary to an inability of the kidneys to excrete solutes and water. We found instead that rats with experimental chronic renal failure constantly lost body water, because their kidneys could not sufficiently concentrate the urine. Physiological adaptation to body water loss, termed aestivation, is an evolutionary conserved survival strategy that relies on complex physiologic-metabolic adjustment across multiple organs to prevent otherwise lethal dehydration. We show that rats with chronic renal failure utilize these ancient water conservation motifs to successfully stabilize their…
LEUKOTRIENE RECEPTORS ON HUMAN PULMONARY VASCULAR ENDOTHELIUM
1995
1. Cysteinyl-leukotrienes cause contractions and/or relaxations of human isolated pulmonary vascular preparations. Although, the localization and nature of the receptors through which these effects are mediated have not been fully characterized, some effects are indirect and not mediated via the well-described LT1 receptor. 2. In human pulmonary veins (HPV) with an intact endothelium, leukotriene D4 (LTD4) induced contraction above basal tone. This response was observed at lower concentrations of LTD4 in the presence of nitric oxide synthase inhibitor N omega-nitro-L-arginine (L-NOARG). Contractions (in the absence and presence of L-NOARG) were partially blocked by the LT1 antagonists (MK 5…