How to Trip Rapid Review

Step 1: Select articles relevant to your search (remember the system is only optimised for single intervention studies)

Step 2: press

Step 3: review the result, and maybe amend the or if you know better! If we're unsure of the overall sentiment of the trial we will display the conclusion under the article title. We then require you to tell us what the correct sentiment is.

10,758 results for

Norepinephrine

by
...
Latest & greatest
Alerts

Export results

Use check boxes to select individual results below

SmartSearch available

Trip's SmartSearch engine has discovered connected searches & results. Click to show

10621. Relationship of blood pressure, heart rate and behavioral mood state to norepinephrine kinetics in younger and older men following caffeine ingestion. (Abstract)

Relationship of blood pressure, heart rate and behavioral mood state to norepinephrine kinetics in younger and older men following caffeine ingestion. To examine age-related differences in blood pressure, heart rate, behavioral mood state and norepinephrine kinetics after caffeine ingestion in younger and older men.Placebo-controlled, double-blind study.General Clinical Research Center, University of Vermont.10 older (O) (65-80 y) and 10 younger (Y) (19-26 y) healthy men who were moderate (...) consumers of caffeine (Y= 126+/-30 mg/d; O = 160 44 mg/d:NS; mean +/- s.e.m.).All volunteers were characterized for fasting plasma glucose, insulin and caffeine levels, body composition, anthropometry, physical activity, and energy intake. Before and after placebo and caffeine ingestion (5 mg/kg fat-free mass) test days, the following variables were measured in all subjects: heart rate, blood pressure, mood state, and norepinephrine concentrations (NEconc), appearance (NEapp) and clearance (NEcl

1998 European journal of clinical nutrition Controlled trial quality: uncertain

10622. Nonselective beta-blockade enhances pressor responsiveness to epinephrine, norepinephrine, and angiotensin II in normal man. (Abstract)

Nonselective beta-blockade enhances pressor responsiveness to epinephrine, norepinephrine, and angiotensin II in normal man. Nonselective beta-blockers increase peripheral vascular resistance and, sometimes, blood pressure (BP); increased responsiveness to circulating pressor agents could be one of the underlying mechanisms. Heart rate (HR) and BP responses to graded intravenous infusions of epinephrine, norepinephrine, and angiotensin II were recorded after placebo and then after 4 wk of beta (...) -blocker treatment (nadolol or propranolol, 240 mg/day) in 10 healthy young men. Adequacy of beta-blockade was demonstrated by a mean 31% decrease in HR response to bicycle exercise, with no differences between the two beta-blockers. Under placebo conditions epinephrine lowered diastolic BP and raised HR; these effects were reversed during treatment with beta-blockers. beta-Blockade potentiated BP responses to norepinephrine and angiotensin II: Thirty-five percent less norepinephrine and 52% less

1984 Clinical pharmacology and therapeutics

10623. Intravenous cocaine increases plasma epinephrine and norepinephrine in humans. (Abstract)

Intravenous cocaine increases plasma epinephrine and norepinephrine in humans. Cocaine has been shown to activate the sympathoadrenal system in both animal and human studies. Controlled human studies have found inconclusive results regarding whether acute cocaine treatment elevates plasma epinephrine and norepinephrine concentrations. The purpose of this study was to investigate whether commonly abused doses of cocaine increase plasma epinephrine and norepinephrine concentrations in humans (...) , in a double-blind, placebo-controlled study. Five male cocaine users were given an intravenous injection of 0.46 mg/kg dose of cocaine or placebo, on two consecutive days. Plasma epinephrine and norepinephrine concentrations were significantly increased in response to cocaine injection compared to placebo. Peak plasma epinephrine and norepinephrine concentrations were reached 3 and 12 min after cocaine injection, respectively. While changes in epinephrine levels following cocaine were correlated

2001 Pharmacology, biochemistry, and behavior

10624. Norepinephrine alters exercise oxygen consumption in heart failure patients. (Abstract)

Norepinephrine alters exercise oxygen consumption in heart failure patients. The primary aim of this research was to evaluate the effect of acute norepinephrine (NE) infusion on the exercise oxygen utilization in heart failure patients as compared with healthy adults.Eleven healthy adults and 10 patients with NYHA class II-III heart failure (ejection fraction <40%) who were not on beta-blocker therapy underwent steady state exercise under placebo or NE infusion conditions, followed by maximal

2000 Medicine and science in sports and exercise

10625. Interactions between insulin and norepinephrine on blood pressure and insulin sensitivity. Studies in lean and obese men. Full Text available with Trip Pro

Interactions between insulin and norepinephrine on blood pressure and insulin sensitivity. Studies in lean and obese men. To explore the interactions between insulin action and norepinephrine (NE) on blood pressure and muscle vascular resistance, we studied seven lean (66 +/- 1 kg) sensitive and seven age-matched obese (96 +/- 3 kg) insulin-resistant men after an overnight fast. Both groups were normotensive; however, the obese exhibited higher basal blood pressure, 90.8 +/- 2.2 vs. 83.4

1994 Journal of Clinical Investigation

10626. Prejunctional angiotensin II receptors. Facilitation of norepinephrine release in the human forearm. Full Text available with Trip Pro

Prejunctional angiotensin II receptors. Facilitation of norepinephrine release in the human forearm. To determine if peripheral angiotensin II (Ang II) prejunctional receptors facilitating NE release exist in humans, we used [3H]NE kinetic methodology to measure forearm NE spillover during intrabrachial arterial Ang II infusions in eight normal male subjects. We used the following protocol to optimize conditions for demonstrating these receptors: (a) lower body negative pressure (-15 mmHg

1994 Journal of Clinical Investigation

10627. Pheochromocytoma in the Horse and Measurement of Norepinephrine Levels in Horses Full Text available with Trip Pro

Pheochromocytoma in the Horse and Measurement of Norepinephrine Levels in Horses Ten cases of pheochromocytoma in horses were obtained from the literature and a computer search of medical records. The clinical, laboratory and pathological features of pheochromocytoma in horses were reviewed. Pheochromocytoma is a catecholamine secreting tumor which tends to occur in older horses without breed or sex predisposition. It is usually unilateral adrenal medullary in location and benign. Malignancy (...) was present in one horse. The most common clinical signs were sweating, tachycardia, tachypnea, muscle tremor and anxiety; however the tumor may be asymptomatic. Clinical signs were nonspecific and could be confused with other diseases, especially abdominal pain. Hyperglycemia is a consistent finding. Venous norepinephrine levels were measured in normal horses. Norepinephrine measurements may prove to be a diagnostic aid in horses with pheochromocytoma.

1984 The Canadian Veterinary Journal

10628. Measurement of regional neuronal removal of norepinephrine in man. Full Text available with Trip Pro

Measurement of regional neuronal removal of norepinephrine in man. We describe here and validate an in vivo technique to measure the regional proportionate removal of norepinephrine (NE) by neuronal uptake (Uptake1) in man. The measurement is based on the steady-state arterial and venous concentrations of tritiated NE and tritiated isoproterenol (ISO) during simultaneous infusion of both. The validity of this technique depends on the removal of circulating NE, but not of ISO, by sympathetic (...) with desipramine decreased significantly the removal of NE to virtually exactly that of ISO. The difference in NE and ISO clearances by arm tissues was therefore completely accounted for by Uptake1. About 15% of infused NE which is removed in the arm is removed by Uptake1. The ability to measure regional Uptake1 should contribute to better understanding of the relationship between circulating levels of plasma NE and sympathetic neural activity and may allow detection of abnormalities of neuronal norepinephrine

1985 Journal of Clinical Investigation

10629. Tracer norepinephrine kinetics in coronary circulation of patients with heart failure secondary to chronic pressure and volume overload. Full Text available with Trip Pro

Tracer norepinephrine kinetics in coronary circulation of patients with heart failure secondary to chronic pressure and volume overload. Controversy exists over the nature of the abnormality in cardiac sympathetic nerves in heart failure. In the cardiomyopathy of the Syrian hamster, reduction in tissue stores and increased turnover of norepinephrine is clearly associated with excessive sympathetic stimulation but in animal models and humans with heart failure secondary to mechanical overload (...) there is evidence for depression of neuronal uptake. Because norepinephrine is both released and taken up by sympathetic fibers it is impossible to assess norepinephrine kinetics in an intact heart without separating these two functions. A technique for doing so has recently been developed in normal dogs and we therefore acquired similar data in humans with heart failure secondary to chronic pressure and volume overload. The technique involves the combination of transient norepinephrine tracer coronary sinus

1985 Journal of Clinical Investigation

10630. Developmental Changes in Response of Dog Isolated Ventricular Myocardium to Norepinephrine Full Text available with Trip Pro

Developmental Changes in Response of Dog Isolated Ventricular Myocardium to Norepinephrine There are maturational changes of myocardial function and response to inotropic agents. Because of incomplete myocardial sympathetic innervation, neonatal myocardium may be more sensitive to norepinephrine than is adult myocardium. We tested this hypothesis by using isolated trabecular muscle from two groups of puppies and from adult dogs. The muscles were exposed to norepinephrine at concentrations of 1 (...) x 10(-10) to 1 x 10(-4) M, and indices of isometric and isotonic contraction were measured. Active tension and maximum rate of contraction increased in all age groups with norepinephrine. Adult dogs were more sensitive than puppies to the arrhythmogenic effect of norepinephrine. Although there was no strictly significant difference statistically, there appeared to be an age-related increase in the dose at which 50% of the maximum effect of the drug was achieved (ED50). Total contraction time

1983 Texas Heart Institute Journal

10631. Effects of norepinephrine infusion on myocardial high-energy phosphate content and turnover in the living rat. Full Text available with Trip Pro

Effects of norepinephrine infusion on myocardial high-energy phosphate content and turnover in the living rat. Using 31P-nuclear magnetic resonance, we studied the relationship between myocardial high-energy phosphate content and flux values for the creatine kinase reaction in the living rat under inotropic states achieved during norepinephrine infusion and halothane anesthesia. Under 2% halothane anesthesia (n = 4), 1% halothane anesthesia (n = 5) and norepinephrine infusion (n = 4), rats (...) developed rate-pressure products of 19.5 +/- 1.6, 32.0 +/- 3.5, and 48.5 +/- 2.0 X 1,000 mmHg/min, respectively. Adenosine triphosphate content was not affected by inotropic state, ranging from 24.3 +/- 1.1 to 25.6 +/- 1.1 mumol/g dry weight, but creatine phosphate content varied inversely and reversibly with cardiac performance from 45.6 +/- 6.0 under 2% halothane to 26.0 +/- 6.5 mumol/g dry weight during norepinephrine infusion. The flux values for the creatine kinase reaction were 15.4 +/- 4.6, 20.5

1987 Journal of Clinical Investigation

10632. Norepinephrine metabolism in humans. Kinetic analysis and model. Full Text available with Trip Pro

Norepinephrine metabolism in humans. Kinetic analysis and model. The present study was undertaken to quantify more precisely and to begin to address the problem of heterogeneity of the kinetics of distribution and metabolism of norepinephrine (NE) in humans, by using compartmental analysis. Steady-state NE specific activity in arterialized plasma during [3H]NE infusion and postinfusion plasma disappearance of [3H]NE were measured in eight healthy subjects in the supine and upright positions

1987 Journal of Clinical Investigation

10633. Baroreflex control of plasma norepinephrine and heart period in healthy subjects and diabetic patients. Full Text available with Trip Pro

Baroreflex control of plasma norepinephrine and heart period in healthy subjects and diabetic patients. Resting diabetic patients may have excessively rapid heart rates, reduced heart rate variability, and subnormal plasma catecholamine levels. Although all of these abnormalities may relate in some way to baroreceptor reflex function, there have been surprisingly few attempts to evaluate systematically baroreflex mechanisms in diabetic patients. Accordingly, we studied autonomic responses over (...) a range of pharmacologically induced arterial pressure changes in 10 unselected young adult insulin-dependent diabetic patients who had no symptoms of autonomic neuropathy, and 12 age-matched nondiabetic subjects. Sympathetic responses were estimated from antecubital vein plasma norepinephrine levels, and parasympathetic responses were estimated from electrocardiographic R-R intervals and their variability (standard deviation). Both were correlated with other noninvasive indexes of peripheral

1986 Journal of Clinical Investigation

10634. Plasma dihydroxyphenylglycol and the intraneuronal disposition of norepinephrine in humans. Full Text available with Trip Pro

Plasma dihydroxyphenylglycol and the intraneuronal disposition of norepinephrine in humans. We examined plasma levels of the sympathetic neurotransmitter norepinephrine (NE) and its deaminated metabolite dihydroxyphenylglycol (DHPG) during supine rest in healthy human subjects and in sympathectomized patients, during physiological (tilt) or pharmacological (yohimbine, clonidine) manipulations known to affect sympathetically mediated NE release, during blockade of neuronal uptake of NE (uptake-1

1988 Journal of Clinical Investigation

10635. Increased renal secretion of norepinephrine and prostaglandin E2 during sodium depletion in the dog. Full Text available with Trip Pro

Increased renal secretion of norepinephrine and prostaglandin E2 during sodium depletion in the dog. To determine whether vasoactive renal hormones modulate renal blood flow during alterations of sodium balance, simultaneous measurements of arterial and renal venous concentrations of norepinephrine and prostaglandin E2 (PGE2) and of plasma renin activity, as well as renal blood flow and systemic hemodynamics were carried out in 24 sodium-depleted and 28 sodium-replete anesthetized dogs (...) groups. The arterial plasma renin activity and concentration of norepinephrine were higher in the sodium-depleted animals than in the controls; the arterial concentration of PGE2 was equal in both groups. The renal venous plasma renin activity was higher in the sodium-depleted dogs. Similarly, the renal venous norepinephrine concentration was higher in the sodium-depleted dogs than in the controls (457 +/- 44 vs. 196 +/- 25 pg/ml; P < 0.01); renal venous PGE2 concentration was also higher

1980 Journal of Clinical Investigation

10636. Effect of Diet and Cold Exposure on Norepinephrine Turnover in Brown Adipose Tissue of the Rat Full Text available with Trip Pro

Effect of Diet and Cold Exposure on Norepinephrine Turnover in Brown Adipose Tissue of the Rat Brown adipose tissue (BAT) is an important site of adaptive changes in thermogenesis in the rat. The sympathetic nervous system, which richly supplies BAT, is thought to play an important role in the regulation of BAT thermogenesis because catecholamines stimulate and beta adrenergic blocking agents inhibit oxygen consumption in this tissue. The present studies were carried out to assess directly (...) sympathetic activity in BAT in response to cold exposure and to changes in dietary intake, both of which alter heat production in the rat. Sympathetic activity was determined from the rate of norepinephrine (NE) turnover in interscapular brown adipose tissue (IBAT) after preliminary experiments validated the use of NE turnover techniques in IBAT. Acute exposure to 4 degrees C increased NE turnover in IBAT 4- to 12-fold compared with ambient temperature controls, depending upon the interval over which

1982 Journal of Clinical Investigation

10637. Lateral hypothalamic lesions and norepinephrine turnover in rats. Full Text available with Trip Pro

Lateral hypothalamic lesions and norepinephrine turnover in rats. Animals with lateral hypothalamic lesions lost significantly more weight in the 18 h following this lesion than did sham-operated animals or rats with cerebral cortical lesions deprived of food for the same time period. In the acutely fasted sham-operated animals the turnover of norepinephrine in interscapular brown adipose tissue, heart, and pancreas was slowed but in fasted rats with lateral hypothalamic lesions norepinephrine (...) turnover rates were three- to ninefold faster in all three organs. Exposure to the cold (4 degrees C) significantly increased norepinephrine turnover in the interscapular brown adipose tissue, heart, and pancreas of fasted sham-operated rats, but did not further increase the rate of turnover in lateral hypothalamic-lesioned rats. Rats with lesions in the cerebral cortex responded in a fashion similar to that of the sham-operated animals. Gastric erosions and microhemorrhagic gastric mucosa were

1983 Journal of Clinical Investigation

10638. Whole Body Clearance of Norepinephrine. THE SIGNIFICANCE OF ARTERIAL SAMPLING AND OF SURGICAL STRESS Full Text available with Trip Pro

Whole Body Clearance of Norepinephrine. THE SIGNIFICANCE OF ARTERIAL SAMPLING AND OF SURGICAL STRESS The whole body clearance of norepinephrine (NE) was measured in seven patients pre- and postoperatively. L[(3)H]NE was infused intravenously for 90 min and steady-state concentrations of L[(3)H]NE were measured at 75 and 90 min in both arterial and peripheral venous blood. Preoperatively, in the resting supine position, the clearance values based on arterial and venous sampling averaged 1.4

1983 Journal of Clinical Investigation

10639. Norepinephrine-stimulated hypertrophy of cultured rat myocardial cells is an alpha 1 adrenergic response. Full Text available with Trip Pro

Norepinephrine-stimulated hypertrophy of cultured rat myocardial cells is an alpha 1 adrenergic response. We have shown recently that norepinephrine stimulates muscle cell hypertrophy in primary cultures from the neonatal rat ventricle and that this stimulation is not blocked by the beta adrenergic antagonist propranolol. The present study was done to define the adrenergic specificity of the myocyte hypertrophic response to norepinephrine. 90% pure, single-cell cultures of nongrowing myocytes (...) were maintained in serum-free medium 199 with transferin and insulin. Myocyte size was quantitated 48 h after addition of adrenergic agents, by measuring cell volume, cell surface area, and cell protein. L-norepinephrine increased myocyte size to a maximum 150% of control; half-maximum effect was obtained at a concentration of 0.2 microM. This increase in cell size was inhibited by the nonselective alpha adrenergic antagonist phentolamine and by the alpha 1 adrenergic antagonists prazosin

1983 Journal of Clinical Investigation

10640. Effect of total hepatectomy and administration of branched-chain amino acids on regional norepinephrine, dopamine, and amino acids in rat brain. Full Text available with Trip Pro

Effect of total hepatectomy and administration of branched-chain amino acids on regional norepinephrine, dopamine, and amino acids in rat brain. In rats after total hepatectomy, the effect of infusing glucose alone or combined with branched-chain amino acids on amino acid concentrations in plasma and cerebral cortex and on catecholamine levels in eight different regions of the brain was studied. Infusion of branched-chain amino acids reduced the accumulation of tryptophan, phenylalanine (...) , and tyrosine in plasma, while in cerebral cortex, the concentrations of phenylalanine and tyrosine were normalized and that of tryptophan was reduced greatly. In rats with hepatectomy and glucose infusion alone, norepinephrine levels were decreased in seven of eight brain regions with the exception of striatum, while dopamine was reduced significantly in striatum only. Infusion of branched-chain amino acids resulted in higher norepinephrine in cortex, mesencephalon, and hypothalamus and higher striatal

1983 Annals of Surgery

To help you find the content you need quickly, you can filter your results via the categories on the right-hand side >>>>