Search results for "Vasoconstrictor Agents"
showing 10 items of 62 documents
Nitric Oxide Opposes Myogenic Pressure Responses Predominantly in Large Arterioles In Vivo
1998
Abstract —A myogenic vasoconstriction may amplify the effects of circulating vasoconstrictors. In cremaster arterioles, the contribution of a myogenic component to the constriction on intravenous infusion of norepinephrine (NE) or angiotensin II (Ang II) was studied. Second, the role of endothelium-derived nitric oxide (NO) in the control of these myogenic constrictions and its site of action in the resistance vascular bed was investigated. In 30 anesthetized (pentobarbital) hamsters, the cremaster was prepared for intravital microscopy, and a pneumatic vessel occluder was placed around the aorta to vary blood pressure in the hindquarter of the animal. Intravenous infusion of NE (0.5 nmol/…
Potential Functional Significance of Brain-Type and Muscle-Type Nitric Oxide Synthase I Expressed in Adventitia and Media of Rat Aorta
1999
Abstract —Skeletal muscle and myocardium express μNOS I, an elongated splice variant of neuronal-type nitric oxide (NO) synthase (NOS I), and NOS III, endothelial-type NO synthase, respectively. This study was designed to elucidate whether vascular smooth muscle also contains a constitutively expressed NO synthase isoform. In the rat, μNOS I contains an insert of 102 nucleotides after nucleotide 2865 of the cDNA, yielding a protein of 164 kd. Reverse transcription-polymerase chain reaction with primers flanking this insert and with insert-specific primers indicated that endothelium-denuded rat aorta expresses both brain-type NOS I and μNOS I. RNase protection analyses with an antisense RNA…
Comparative effects of the novel vasotocin analogue F-180 vs. vasopressin and terlipressin on systemic and splanchnic isolated vessels from portal hy…
2001
F-180 has been proposed as a new vasopressin analogue for the treatment of portal hypertension. This study investigates the contractile profile of F-180 compared to vasopressin and its analogue terlipressin on isolated systemic and splanchnic vessels from sham-operated and partial portal vein ligated (PPVL) rats. F-180 (10(-9)-10(-6) M), vasopressin (10(-11)-10(-8) M) and terlipressin (10(-9)-10(-4) M) induced contraction of the mesenteric vein, aorta, iliac, tail and mesenteric arteries. The order of potency in these vessels was vasopressin (pD2 approximately 9)F-180 (pD2 approximately 8)terlipressin (pD2 approximately 6). Significant (P0.01) differences between sham-operated and PPVL rats…
Contractile effects of arginine analogues on human internal thoracic and radial arteries
2000
Abstract Objectives: Plasma levels of endogenous guanidino-substituted analogues of L -arginine are increased in various pathologic conditions. In the present study we determined the effects of some of these compounds on basal and stimulated release of nitric oxide in human internal thoracic and radial arteries. Methods: Rings of human internal thoracic and radial arteries were obtained from 16 multiorgan donors. The rings were suspended in organ baths for isometric recording of tension. Results: N G -monomethyl L -arginine (10 –6 to 10 –3 mol/L) and N G ,N G -dimethyl L -arginine (10 –6 to 10 –3 mol/L) caused concentration- and endothelium-dependent contractions. Maximal force of contracti…
Acute and Chronic Captopril, but Not Prazosin or Nifedipine, Normalize Alterations in Adrenergic Intracellular Ca2+ Handling Observed in the Mesenter…
2004
The effect of hypertension and acute (36-h) or chronic (from age 6 to 16 weeks) antihypertensive treatment with prazosin (2 mg kg(-1) per day), nifedipine (50 mg kg(-1) per day), or captopril (50 mg kg(-1) per day) on Ca2+ mobilization due to alpha1-adrenoceptor activation was analyzed in functional studies using arterial rings [four conductance/distributing vessels: aorta, main mesenteric, iliac, and tail arteries and two resistance vessels; first and second small mesenteric artery branches obtained from spontaneously hypertensive rats (SHR, 6 and 16 weeks old) and age-matched Wistar Kyoto rats (WKY)]. Maximal response to noradrenaline in the presence of extracellular Ca2+ is not affected …
Influence of anxiety and anesthetic vasoconstrictors upon hemodynamic parameters during dental procedures in controlled hypertensive and non-hyperten…
2020
Background To determine the influence of dental anxiety and the vasoconstrictor used in local anesthesia upon different hemodynamic parameters - systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR) and peripheral oxygen saturation (SatO2) - during dental extraction and oral hygiene. The safety of local anesthesia with vasoconstrictor in patients with medically controlled hypertension was also assessed. Material and methods A total of 159 patients were divided into two groups according to the dental treatment received: tooth extraction (n = 106) and oral hygiene (n = 53). The hemodynamic parameters (SBP, DBP, HR and SatO2) were recorded throughout dental treatment. Patient anxi…
A Case of Cardiomyopathy Due to Premature Ductus Arteriosus Closure: The Flip Side of Paracetamol.
2017
Paracetamol (acetaminophen or N-acetyl-p-aminophenol) is considered a safe analgesic and antipyretic nonsteroidal antiinflammatory drug commonly used during pediatric ages and during pregnancy. We report on a term neonate with closed ductus arteriosus, severe cardiomyopathy, right ventricular dysfunction, and functional stenosis of pulmonary arteries at birth after maternal self-medication with paracetamol and consumption of polyphenol-rich foods in late pregnancy. This drug, especially when associated with other vasoconstrictors (such as polyphenols), interferes with prostaglandin metabolism, which seriously accentuates the intrauterine ductus arteriosus constriction and leads to pharmacol…
Histaprodifens: synthesis, pharmacological in vitro evaluation, and molecular modeling of a new class of highly active and selective histamine H(1)-r…
2000
A new class of histamine analogues characterized by a 3, 3-diphenylpropyl substituent at the 2-position of the imidazole nucleus has been prepared outgoing from 4,4-diphenylbutyronitrile (4b) via cyclization of the corresponding methyl imidate 5b with 2-oxo-4-phthalimido-1-butyl acetate or 2-oxo-1,4-butandiol in liquid ammonia, followed by standard reactions. The title compounds displayed partial agonism on contractile H(1) receptors of the guinea-pig ileum and endothelium-denuded aorta, respectively, except 10 (histaprodifen; 2-[2-(3, 3-diphenylpropyl)-1H-imidazol-4-yl]ethanamine) which was a full agonist in the ileum assay. While 10 was equipotent with histamine (1), methylhistaprodifen (…
A critical role for TNFα in the selective attachment of mononuclear leukocytes to angiotensin-II-stimulated arterioles
2007
Abstract Angiotensin II (Ang-II) exerts inflammatory activity and is involved in different cardiovascular disorders. This study has evaluated the involvement of tumor necrosis factor alpha (TNFα) in the leukocyte accumulation elicited by Ang-II. Ang-II (1 nM intraperitoneally in rats) induced TNFα release at 1 hour followed by neutrophil and mononuclear cell recruitment. The administration of an antirat TNFα antiserum had no effect on Ang-IIinduced neutrophil accumulation but inhibited the infiltration of mononuclear cells and reduced CC chemokine content in the peritoneal exudate. Pretreatment with either an anti-TNFα or an anti-IL-4 antiserum decreased Ang-II-induced arteriolar mononuclea…
Causal linear parametric model for baroreflex gain assessment in patients with recent myocardial infarction
2001
Spectral and cross-spectral analysis of R-R interval and systolic arterial pressure (SAP) spontaneous fluctuations have been proposed for noninvasive evaluation of baroreflex sensitivity (BRS). However, results are not in good agreement with clinical measurements. In this study, a bivariate parametric autoregressive model with exogenous input (ARXAR model), able to divide the R-R variability into SAP-related and -unrelated parts, was used to quantify the gain (αARXAR) of the baroreflex regulatory mechanism. For performance assessing, two traditional noninvasive methods based on frequency domain analysis [spectral, baroreflex gain by autogressive model (αAR); cross-spectral, baroreflex gain…