Catecholamines (Total 34610 Papers Found)

Pheochromocytomas, intra-adrenal paraganglioma, and extra-adrenal sympathetic and parasympathetic paragangliomas are neuroendocrine tumors derived from adrenal chromaffin cells or similar cells in extra-adrenal sympathetic and parasympathetic paraganglia, respectively. Serious morbidity and mortality rates associated with these tumors are related to the potent effects of catecholamines on various organs, especially those of the cardiovascular system. Before any surgical procedure is done, preope ...
1. COS-7 cells transfected with the cDNA of the human dopamine transporter (DAT cells) or the human noradrenaline transporter (NAT cells) were loaded with [3H]-dopamine or [3H]-noradrenaline and superfused with buffers of different ionic composition. 2. In DAT cells lowering the Na+ concentration to 0, 5 or 10 mM caused an increase in 3H-efflux. Cocaine (10 microM) or mazindol (0.3 microM) blocked the efflux at low Na+, but not at 0 Na+. Lowering the Cl- concentration to 0, 5 or 10 mM resulted i ...
Sepsis and lipopolysaccharide (LPS) trigger the systemic release of both cytokines and catecholamines. Cytokines are known to be capable of eliciting a stress hormone response in vivo. The present study sought insight into the effect of noradrenaline on LPS-induced release of tumor necrosis factor alpha (TNF) and interleukin 6 (IL-6) in human whole blood. Whole blood was incubated with LPS for 4 h at 37 degrees C in the presence and absence of noradrenaline and/or specific alpha and beta antagon ...
Little is known about the neural control of female responses to male courtship. Female European starlings in breeding condition with high concentrations of estrogen select mates based on variation in song and approach nest boxes broadcasting male song. In contrast, outside of the breeding season (when estrogen is low) females do not display the same response to male song. The catecholamines dopamine and norepinephrine regulate behaviors important for mate choice such as arousal, attention, sexua ...
Pregnant CD rats were treated subcutaneously with 0, 5 or 10 mg/kg/day of imipramine (IMI) on days 8-20 of gestation. Behavioral and neurochemical endpoints were measured at different postnatal days (PND). Three behavioral tests were conducted: negative geotaxis on PNDs 7-9; auditory startle habituation (ASH) on PNDs 14, 16 and 18; locomotor activity before and after intraperitoneal (i.p.) injection of saline or 0.5 mg/kg d-amphetamine on PND 21. Catecholamine levels, B-adrenergic and muscarinic ...
In mammalian striatal tissue and cat platelets, [3H]ketanserin labels besides serotonin-S2 receptors nonserotonergic saturable binding sites. The sites have been distinguished and characterized in [3H]ketanserin binding assays by selective inhibition with tetrabenazine (Ki = 4 nM), a monoamine depleting agent. In rats, the nonserotonergic ketanserin sites were enriched in the striatum (KD = 12.4 +/- 0.3 nM, maximal number of binding sites = 53.2 +/- 11.8 fmol/mg of tissue at pH 7.7, 37 degrees C ...
Hypothalamic norepinephrine (NE) release regulates arterial pressure by altering sympathetic nervous system activity. Because angiotensin (Ang) (1-7) decreases hypothalamic NE release and this effect may be correlated with a diminished NE synthesis, we hypothesize that Ang-(1-7) down-regulates tyrosine hydroxylase (TH), the rate-limiting enzyme in catecholamines biosynthesis. We investigated the effect of Ang-(1-7) on centrally TH activity and expression. TH activity was evaluated by the release ...
Dexfenfluramine has been shown to reduce body weight and lower blood pressure in obese individuals. However. it is not clear whether the blood pressure-lowering effect is due to dexfenfluramine or to the loss of weight. This project was designed to study the effect of a 5-d treatment of dexfenfluramine on blood pressure changes in obese postmenopausal women. Twenty women aged 51-60 y matched for body mass index [BMI (in kg/m2) of 34.5-50.1] were assigned to either the dexfenfluramine group (15 m ...
The Takotsubo cardiomyopathy (TTC), also called ‘‘stress cardiomyopathy’’, ‘‘transient apical ballooning’’ or ‘‘broken heart syndrome’’, is a disorder associated with transient left-ventricular dysfunction in absence of substantial coronary artery disease. The clinical presentation is similar to an acute coronary syndrome with acute chest pain and dyspnea accompanied by ECG changes, such as T wave inversions or mild ST segment elevations, minimal elevation of cardiac enzy ...
Plasma levels of catecholamines and pituitary adrenal hormones were measured in 20 min samples from eight subjects, in one control session and two experimental sessions, while they performed a short-term memory task under quiet of noise conditions. Performing the task led to significant increase in the plasma levels of cortisol, adrenaline and noradrenaline, whereas no variations in growth hormone and dopamine were observed. Similarly, significant changes occurred in urinary catecholamine excret ...
The catecholamine content in adrenergic plexuses and the oxidative enzyme activity (succinate dehydrogenase, lactate dehydrogenase) during cold and emotional stress were studied histochemically in the rat myocardium. An acute short-term cooling led to an increase in the catecholamine fluorescence intensity and succinate dehydrogenase activity, whereas a short-term emotional stress resulted in a decrease in both these parameters. ...
The phosphorylation of the enzyme tyrosine hydroxylase by the cGMP pathway was investigated in chromaffin cells from the bovine adrenal medulla. The nitric oxide donor, sodium nitroprusside, and the natriuretic peptide, C-type natriuretic peptide, which are able to increase cGMP levels and cGMP-dependent protein kinase activity, produced significant increases in the phosphorylation level of tyrosine hydroxylase in a time- and concentration-dependent manner. The pretreatment of the cells with the ...
Intravenous administration of the serotonin agonist, m-chlorophenylpiperazine (m-CPP), produced large, dose-dependent increases in epinephrine, norepinephrine and dopamine in plasma in normal, conscious rats. Elevations in the levels of epinephrine, norepinephrine and dopamine (10-fold, 5-fold and 2-fold, respectively) were markedly reduced in pithed and splanchnic denervated rats, suggesting that CNS mechanisms are primarily responsible for the effect of m-CPP on catecholamines in plasma. The s ...
BACKGROUND AND OBJECTIVES The hemodynamic support of sepsis is now formulated trying to insert terlipressin as salvage drug in catecholamine resistant shock, justifying a broad critical analysis. CONTENTS The analysis included hemodynamic therapies with defined specific goals and new recommendations for fluid resuscitation, vasopressor therapy, and inotropic therapy of septic in adult and pediatric patients. CONCLUSIONS Terlipressin appears as a new but controversial alternative for vasopres ...
Up to 2008, dopamine was the catecholamine that was the most recommended in our intensive care unit (ICU) after fluid resuscitation. However, recently, norepinephrine has become the catecholamine that was most recommended in our ICU after fluid resuscitation. The aim of this study was to determine if there was an efficacy or safety benefit to this protocol therapeutic change in patients with shock admitted to our ICU. The primary outcome variable was ICU mortality. This is a prospective observat ...
The effect of burn injury on blood sugar levels, serum insulin levels and glucose tolerance was studied in male rats. In the burned group (following 50 per cent surface burn injury), the blood sugar level was significantly increased after burn injury in comparison with control uninjured rats. Hyperglycaemia was blocked by injection of phentolamine (10 mg/kg) for 24 h or propranolol (50 micrograms/kg) 30 min before burn or if the animals were adrenalectomized 4 days before injury. Serum insulin l ...
BACKGROUND Activated coagulation Factor XII (FXIIa) infusion increases peripheral resistance (TPR) and mean arterial pressure (MAP) of Brown Norway but not plasma kininogen deficient Brown Norway Katholiek (BNK) rats. FXIIa concentrations are elevated in hypertensive end-stage renal disease patients receiving conventional haemodialysis (CHD). Conversion to nocturnal haemodialysis (NHD) lowers peripheral resistance and MAP. OBJECTIVE To determine whether the plasma coagulation FXIIa-kallikrein- ...
1. Intraperitoneal administration of nialamide, 200 mg/kg, to mice elicited a pronounced increase in motor activity and rectal temperature concomitant with a gradual increase in the concentrations of 5-hydroxytryptamine (5-HT), noradrenaline (NA) and dopamine in the brain.2. In mice treated with L-tryptophan, 300 mg/kg, 1 h before nialamide, the increase in motor activity appeared earlier than after nialamide alone, and the hyperthermia was more pronounced. The increase in 5-HT concentrations in ...
Indices of heart rate variability (HRV) reflect cardiac autonomic tone and may be markedly affected by pheochromocytoma. The effect of pheochromocytoma on HRV was determined by Holter monitoring before diagnosis, under pre-operative α-blockade and 5 and 19 months after surgery in a 40 year-old female. Mean heart rates, although higher under α-blockade, were unchanged by surgery but indices of HRV reflecting both short term (vagally mediated) and longer term (mediated by vagal, sympathetic and ...
Catecholamines mediate surfactant release and smooth muscle tone in the lung by interaction with β-adrenergic receptors (BAR) and adenylate cyclase (AC). This study describes the ontogeny of BAR and AC in rat lung membrane and the role of thyroid hormone in the postnatal increase in BAR. BAR were identified with [3H] dihydroalprenolol ([3H]DHA). Bmax increased from 46±4.9 fmole mg−1 protein to 491 ±39 m±SE from d 18 of gestation to adult levels postnatal d 28. Increases in lung BAR occurre ...
Phaeochromocytoma can have a variety of presentations; however, traumatic hemorrhage into a phaeochromocytoma is a very rare presentation. Diagnosing and managing a critically ill, septic patient with a Phaeochromocytoma can be very challenging. We report a case of 53 years old man with a previously undiagnosed Phaeochromocytoma, who presented initially with bowel perforation following an assault. Following a laparotomy for bowel resection and anastomosis, whilst on the intensive care unit, he d ...
The two-column procedure for plasma catecholamine determination was adopted as a routine diagnostic test. It was found that the recovery of catecholamine added to properly preserved plasma was 65%. The most efficient recovery occurred when the water content of alumina used was above 23%. Both interassay and intra-assay precision were +/- 10% (coefficient of variation). The catecholamine was stable, in properly preserved plasma, for at least 18 days at -20 degrees C. ...
The effects of thyroxine (T4) treatment of rats on the neuronal and extraneuronal uptake and subsequent metabolism of catecholamines in the heart were examined, to determine whether changes in the local dissipation of catecholamines might contribute to the enhanced sympathetic cardiac responses that occur when thyroid hormone levels are elevated. T4-treated rats were injected subcutaneously with L-thyroxine sodium 1 mg kg(-1) on days 1, 3 and 5, and controls were injected with the normal saline ...
Investigations were made on the effects of catecholamine (Cat) infusions with and without ammonia (NH3) on plasma and brain amino acids (AA) and brain neurotransmitters in dogs. Groups of four dogs were infused for 5 h with epinephrine (E), epinephrine + norepinephrine (E + NE), epinephrine + norepinephrine with NH3 during h 4 and 5 (E + NE + NH3), epinephrine + norepinephrine + tryptophan with NH3 during h 4 and 5 (T + E + NE + NH3), or saline (C). Cat decreased (P less than 0.05) plasma Gly, T ...
The tranquilizer reserpine has several effects on adrenal medullary chromaffin-granule membrane vesicles (ghosts). At low concentrations (0.20 +/0 0.12 nmol/mg of membrane protein), reserpine inhibits proton-linked epinephrine uptake but does not affect transmembrane pH and electrical potential gradients. Reserpine apparently binds to and blocks the catecholamine translocator. At intermediate concentrations (14.3 +/- 4.8 nmol/mg of membrane protein), reserpine abolishes the ATP-dependent enhance ...
  • Tracy J Smith,
  • BioEssays : news and reviews in molecular, cellular and developmental biology
  • 1990
Amine acetylation is a diverse topic with importance to the regulation of several physiological processes as well as the metabolism of drugs and environmental chemicals. Arylalkylamine N-acetyltransferase is widely distributed in several species, where this enzyme plays an important role in the seasonal regulation of reproduction and photoperiodism in vertebrates through the pathway of melatonin formation. In insects, this enzyme is involved in monoamine neurotransmitter inactivation and the for ...
Tyrosine is the precursor of catecholamines. Small doses of tyrosine produce tachycardia and hypertension while higher doses produce bradycardia and hypotension in anaesthetised rats. The mechanism of these effects has not been established. An increased synthesis and release of catecholamines has been suggested to be the mechanism. Various pretreatments were given to anaesthetised Wistar rats to study the influence of a blockade of L-tyrosine metabolism and thus a blockade of catecholamine synth ...
Injection of N omega-nitro-L-arginine methyl ester (L-NAME), an L-arginine analogue and a potent inhibitor of nitric oxide (NO) synthase, in dorsolateral periaqueductal gray (PAG) area of freely moving rats at doses from 0.1 to 1 mumol per rat, dose-dependently increased arterial blood pressure (BP). Endothelin-1 (ET-1) injected in the same area at doses from 0.1 to 1 pmol per rat also induced pressor effects. Administration of L-NAME (1 mumol per rat) in the PAG area 10 min before ET-1 signific ...
Tyrosine hydroxylase (TyrH) catalyzes the hydroxylation of tyrosine to form 3,4-dihydroxyphenylalanine in the biosynthesis of the catecholamine neurotransmitters. The activity of the enzyme is regulated by phosphorylation of serine residues in a regulatory domain and by binding of catecholamines to the active site. Available structures of TyrH lack the regulatory domain, limiting the understanding of the effect of regulation on structure. We report the use of NMR spectroscopy to analyze the solu ...
BACKGROUND Pheochromocytoma is a rare catecholamine-producing tumor with an estimated incidence of less than 0.1% in the global population. We present a case of cystic pheochromocytoma that was diagnosed as an incidental finding. The patient presented with abdominal pain and had a history of hypertension. CASE REPORT A 64-year-old man with hypertension presented with a clinical history of intermittent abdominal pain for one year. He denied sweating, palpitations, headache or back pain. He was fo ...
We compared the efficacy and safety of nitrendipine with that of hydralazine in 21 subjects with essential hypertension. Nitrendipine or hydralazine was given in a double-blind manner after a placebo period. Dose was titrated to diastolic blood pressure (BP) less than or equal to 90 mm Hg and the dose established during titration was continued for 5 to 7 wk. Both supine and erect BP were decreased by both drugs, but heart rate was affected only minimally. Myocardial oxygen demand decreased only ...
Journal of Lipid Research Volume 52, 2011 221 Copyright © 2011 by the American Society for Biochemistry and Molecular Biology, Inc. Storing excess energy for future use during starvation is critical for the survival of mammals. Much of this energy is stored in the form of triacylglycerol (TAG) within lipid droplets, which are present most abundantly in adipocytes and which, in turn, accumulate in depots such as subcutaneous and visceral adipose tissue in mice and humans. TAG in lipid droplets i ...
The purpose of this study was to examine the effects of ethanol on heart rate, blood pressure and plasma noradrenaline and adrenaline responses to mental stress, involving reactions to anxiety and excitement produced using a cognitive task with electric shock and a competitive electronic game respectively. Twenty subjects were studied, each subject acting as his own control by participating twice, with and without prior ethanol consumption. Mental stress was associated with significant increases ...
Catheterized rats were subjected to various social conditions and amphetamine treatment and plasma norepinephrine and epinephrine levels were measured. Normal interactions involving another male or female rat did not alter plasma catecholamine levels. Social interactions with a mouse or an amphetamine treated, hyperactive male rat had no effect on plasma epinephrine but increased norepinephrine levels significantly. A low dose of amphetamine given to the catheterized rat increased only plasma no ...
Dopamine plays a critical role in regulation of different renal functions, including glomerular filtration, renin secretion, and sodium excretion. Recent studies have shown that some of the dopamine effects in the proximal tubule may involve hydrogen peroxide (H(2)O(2)) generation by the catecholamine-degrading enzyme monoamine oxidases (MAO). The present study is an investigation of the potential role of H(2)O(2) generated by MAO during dopamine degradation in apoptosis of proximal tubule cells ...
Heart transplantation (HTx) candidates who remain severely symptomatic despite optimal therapy are normally hospitalized. Continuous infusion of intravenous drugs from a portable pump may allow such patients to live fairly active life until a donor heart is found. Among the current potential bridging agents the synthetic β-agonist dobutamine is preferred for inotropic support. Prostaglandin E1 (PGE1), a naturally occurring substance with an eicosanoid structure and potent pulmonary and systemic ...
This study investigated the hemodynamic effects and tolerance of infusion of 10 µg/kg/min enoximone over 7 days in 12 patients (mean age 64.3 years) with severe chronic heart failure (10 NYHA Class III and 2 Class IV) with idiopathic dilated cardiomyopathy. Hemodynamic parameters were measured 10 minutes, 3 hours, 6 hours, 18 hours, 24 hours, and 7 days after the start of infusion. Catecholamines were assayed before the start of the infusion and on day 7. The heart rate increased on an average ...
Studies suggest that psychosocial factors can impact cancer progression. Parallel work in the fields of psychoneuroimmunology and developmental neuroscience have led to the implication of catecholamine hormones (norepinephrine and epinephrine) and their receptors (the β-adrenergic receptors; β-ARs) in regulating cancer progression. In this review we discuss studies that describe the effects of psychological stress as mediated by factors including the catecholamines norepinephrine and epinephri ...
Antecubital venous plasma neuropeptide Y-like immunoreactivity (NPY-LI) and catecholamines were analyzed in six healthy volunteers performing a graded bicycle exercise without medication and after acute administration of clonidine, phentolamine, and nifedipine. During the control exercise, plasma noradrenaline (NA), adrenaline (A), and NPY-LI increased to 17-, 7-, and 3-fold the resting values, respectively, at a maximal workload. Clonidine (300 micrograms p.o.) reduced resting and exercising he ...
1. The effects of Gd3+ on bradykinin- (BK-) induced catecholamine secretion, 45Ca2+ efflux and cytosolic [Ca2+] were studied using bovine adrenal chromaffin cells. 2. BK increased secretion in a Ca2+-dependent manner. From 1 - 100 microM, Gd3+ progressively inhibited secretion induced by 30 nM BK to near-basal levels, however from 0.3 - 3 mM Gd3+ dramatically enhanced BK-induced secretion to above control levels. Gd3+ also increased basal catecholamine secretion by 2 - 3 fold at 1 mM. These effe ...
We present a case of a 19-year old woman who was admitted to our department with a recently, and incidentally, diagnosed severe hypertension [220/140 mmHg systolic/diastolic blood pressure (BP)]. The patient was asymptomatic. The laboratory investigation demonstrated both elevated plasma norepinephrine (1807 pg/ml, normal range 120-350 pg/ml) and 24h urinary free catecholamines (483 µg/24h, normal range <150 µg/24h), making the diagnosis of a catecholamineproducing tumor highly probable. Al ...
BACKGROUND Typical or classical takotsubo cardiomyopathy (TCM) is associated with the characteristic abnormality of a ballooned left ventricular apex with basal segmental hyperkinesis. TCM may not present with the "classical" wall motion abnormalities but can have a variety of segmental wall motion abnormalities. The aim of our work was to assess for any unique identifying factors that can help distinguish typical and atypical variants of TCM. METHODS We studied 11 consecutive patients between ...
Humans risk inadvertent intraperitoneal or intravenous exposure to formaldehyde (HCHO), commonly used for disinfection of implanted or extracorporeal medical devices. Various chemical and physical stresses are known to induce hepatic metallothionein. This study examined the effect of acute parenteral administration of HCHO on induction of hepatic metallothionein synthesis. Adult male CF1 mice were administered HCHO ip and hepatic metallothionein was quantified by the cadmium-radioassay method. H ...
PURPOSE A high percentage of paragangliomas express somatostatin receptors that can be utilized for targeted radioisotope therapy. The aim of this study was to describe and discuss the challenges of treating these tumors with (177)Lu-[DOTA(0),Tyr(3)]octreotate (DOTATATE) radioisotope therapy using established protocols. METHODS AND RESULTS Three paraganglioma patients were treated with 4-5 cycles of (177)Lu-DOTATATE and were evaluated for side effects and response to therapy. Two of the three ...