Search results for "vasodilation"
showing 10 items of 228 documents
β2-adrenoreceptors control human skin microvascular reactivity.
2021
Topical α1- and α2-adrenoreceptor (ADRA1 and 2) agonists are effective in alleviating permanent vasodilation and facial erythema associated with rosacea by inducing skin vasoconstriction. Although β-adrenoreceptor (ADRB) antagonists are used off-label for rosacea, pharmacological and pharmacodynamic data pertaining to these receptors in skin micro-vessels are lacking. Objectives: To analyse the expression of different adrenergic receptors and their contribution to vasoreactivity in skin micro-vessels. Small arteries (500-800 μm) and arterioles (<200 μm) were studied in human foreskin tissue. Specifically, ADR-A1, -A2, -B1 and -B2 expression was assayed by immunofluorescence, polymerase chai…
Heat-evoked vasodilatation in human hairy skin: axon reflexes due to low-level activity of nociceptive afferents.
1996
1. Spreading vasodilatation of the axon reflex type was evoked by contact heat stimulation of the hairy skin in the human forearm (13.3 cm2 stimulus area) and was detected by laser Doppler flowmetry at 8, 19 and 30 mm distance. 2. From a base temperature of 35 degrees C, rapidly rising short heat stimuli (4 degrees C s-1, 2 s plateau) elicited vasodilatation at an average threshold of 39.4 degrees C. For slowly rising sustained heat stimuli (64 s duration) the average threshold was 39.6 degrees C (n.s.) Laser Doppler flowmetry revealed a rapid onset within about 4 s, a long duration of several minutes beyond the end of the stimulus, and a rapid spread of vasodilatation to remote skin areas.…
V2-receptor–mediated relaxation of human renal arteries in response to desmopressin
1999
The effects of deamino-8-D-arginine vasopressin (desmopressin), a V2 receptor antidiuretic agonist, were studied in isolated rings from branches of renal arteries obtained from 22 patients undergoing nephrectomy. The rings were suspended in organ bath chambers for isometric recording of tension. In precontracted rings with norepinephrine (10(-6) to 3 x 10(-6) mol/L), desmopressin (10(-11) to 3 x 10(-7) mol/L) caused endothelium-dependent relaxation (81%+/-4% reversal of the initial contraction in arteries with endothelium; 20%+/-4% in arteries without endothelium; P < .05). The relaxation to desmopressin in rings with endothelium was reduced significantly by indomethacin (10(-6) mol/L) and …
Endothelium-dependent relaxation of human saphenous veins in response to vasopressin and desmopressin
1997
Purpose: The goal of this study was to determine the effects of vasopressin and the selective V 2 -receptor agonist desmopressin on human saphenous veins, with special emphasis on endothelium-mediated responses. Methods: Human saphenous vein segments were obtained from 35 patients undergoing coronary bypass surgery. Paired segments, one normal and the other deendothelized by gentle rubbing, were mounted for isometric recording of tension in organ baths. Concentration-response curves to vasopressin and desmopressin were determined in the presence and in the absence of either the V,-receptor antagonist d(CH 2 ) 5 Tyr(Me)AVP (10 −6 mol/L), the V 1 -V 2 receptor antagonist desGly-d(CH 2 ) 5 D-T…
Non invasive evaluation of endothelial function in patients with Anderson-Fabry disease.
2005
AIM: Fabry's disease is an X-linked recessive abnormality of glycosphingolipid metabolism. Increased levels of endothelial prothrombotic factors have recently been demonstrated in Fabry's disease, whereas endothelial function has not been studied using high resolution ultrasound. METHODS: We enrolled 6 patients (4 male, 2 female; mean age, 37 years) and 12 sex matched control subjects (mean age, 37 years). Patients' exclusion criteria included a prior history of cardiac disease, diabetes and treated or untreated hypertension. Patients underwent: anamnesis, physical examination, EKG, 2-dimensional echocardiography with tissue Doppler, measurement of body weight and height, blood pressure. Bi…
Effect of acute systemic hypoxia on human cutaneous microcirculation and endothelial, sympathetic and myogenic activity
2015
The regulation of cutaneous vascular tone impacts vascular vasomotion and blood volume distribution as a challenge to hypoxia, but the regulatory mechanisms yet remain poorly understood. A skin has a very compliant circulation, an increase in skin blood flow results in large peripheral displacement of blood volume, which could be controlled by local and systemic regulatory factors. The aim of this study was to determine the acute systemic hypoxia influence on blood flow in skin, local regulatory mechanism fluctuations and changes of systemic hemodynamic parameters. Healthy subjects (n=11; 24.9±3.7years old) participated in this study and procedures were performed in siting position. After 2…
Rosuvastatin Prevents Conduit Artery Endothelial Dysfunction Induced by Ischemia and Reperfusion by a Cyclooxygenase-2–Dependent Mechanism
2010
ObjectivesThe purpose of this study was to determine whether single-dose rosuvastatin (40 mg) protects against ischemia and reperfusion (IR)–induced endothelial dysfunction in humans and whether this effect is cyclooxygenase (COX)-2 dependent.BackgroundAnimal studies have demonstrated that rosuvastatin can limit damage and improve recovery after IR.MethodsIn a double-blind, parallel design, 20 volunteers were randomized to a single dose of oral rosuvastatin (40 mg) or placebo. Twenty-four hours later, endothelium-dependent, flow-mediated dilation (FMD) of the radial artery was measured before and after IR (15 min of upper arm ischemia followed by 15 min of reperfusion). In a separate protoc…
The effects of arterial carbon dioxide partial pressure and sevoflurane on capillary venous cerebral blood flow and oxygen saturation during cranioto…
2009
Intraoperative routine monitoring of cerebral blood flow and oxygenation remains a technological challenge. Using the physiological principle of carbon dioxide reactivity of cerebral vasculature, we investigated a recently developed neuromonitoring device (oxygen-to-see, O2C device) for simultaneous measurements of regional cerebral blood flow (rvCBF), blood flow velocity (rvVelo), oxygen saturation (srvO2), and hemoglobin amount (rvHb) at the capillary venous level in patients subjected to craniotomy. METHODS: Twenty-six neurosurgical patients were randomly assigned to anesthesia with 1.4% or 2.0% sevoflurane end-tidal concentration. After craniotomy, a fiberoptic probe was applied on a ma…
Thoracoscopic sympathectomy at the T2 or T3 level facilitates bradykinin-induced protein extravasation in human forearm skin.
2010
Background. The endogenous peptide bradykinin (BK) is an inflammatory mediator that induces nociceptor activation and sensitization as well as protein extravasation and vasodilation. Objective. To test the hypothesis if sympathectomy affects BK-induced inflammation in humans. Methods. Dermal microdialysis was employed on the volar forearm in 10 patients (21–41 years) with regional hyperhidrosis before and three months after preganglionic endoscopic transthoracic sympathetic clipping (ETSC) at the T2 or T3 level and in 10 healthy volunteers (22–36 years). After 60 minutes perfusion with Ringer's solution microdialysis fibers were perfused with BK 10−7 M and 10−5 M for 30 minutes followed …
Relaxation and cyclic GMP levels in response to sildenafil in human pulmonary arteries from donors.
2005
We measured cyclic GMP formation and relaxation response to sildenafil given either alone or in combination with sodium nitroprusside (SNP) in pulmonary arteries obtained from 13 multi-organ donors. Sildenafil (10(-9)-10(-4) M) caused concentration-dependent relaxations and amplified the relaxation induced by SNP. Relaxation was unaffected by endothelium removal or by pre-treatment with the inhibitor of nitric oxide synthase L-NMMA (10(-4) M). SNP (10(-7) M) caused elevation of cyclic GMP levels that was potentiated by sildenafil (10(-6) M). Thus, the enhancement of SNP-induced relaxation by sildenafil is mainly due to an increase in cyclic GMP accumulation.