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Norepinephrine

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10741. General anesthetic actions on norepinephrine, dopamine, and gamma-aminobutyric acid transporters in stably transfected cells. (Abstract)

General anesthetic actions on norepinephrine, dopamine, and gamma-aminobutyric acid transporters in stably transfected cells. The effects of general anesthetics on neurotransmitter uptake by plasma membrane transporters are controversial. We analyzed the effects of representative volatile and IV general anesthetics on recombinant transporters for norepinephrine (human NET), dopamine (rat DAT), or gamma-aminobutyric acid (rat GAT-1) stably expressed in a porcine kidney cell line (LLC-PK(1 (...) transmission. Recombinant transporters for norepinephrine and dopamine were sensitive to certain volatile and IV anesthetics, whereas gamma-aminobutyric acid transporters were insensitive. These anesthetic- and neurotransmitter-specific effects may underlie some of the secondary effects of general anesthetics.

2002 Anesthesia and Analgesia

10742. Subthreshold membrane potential oscillation mediates the excitatory effect of norepinephrine in chronically compressed dorsal root ganglion neurons in the rat. (Abstract)

Subthreshold membrane potential oscillation mediates the excitatory effect of norepinephrine in chronically compressed dorsal root ganglion neurons in the rat. Injured dorsal root ganglion (DRG) neurons often develop adrenergic sensitivity. To investigate the mechanisms of this phenomenon, the effects of norepinephrine (NE) on membrane potential of large- and medium-sized A-type neurons from chronically compressed DRG were recorded electrophysiologically in vitro. NE induced a depolarization

2003 Pain

10743. The effects of general anesthetics on norepinephrine release from isolated rat cortical nerve terminals. (Abstract)

The effects of general anesthetics on norepinephrine release from isolated rat cortical nerve terminals. Intravenous and volatile general anesthetics inhibit norepinephrine (NE) release from sympathetic neurons and other neurosecretory cells. However, the actions of general anesthetics on NE release from central nervous system (CNS) neurons are unclear. We investigated the effects of representative IV and volatile anesthetics on [(3)H]NE release from isolated rat cortical nerve terminals (...) and transmitter-specific effects on transmitter release: therapeutic concentrations of some anesthetics stimulate basal, but not evoked, norepinephrine release, in contrast to evoked glutamate release, which is inhibited.

2002 Anesthesia and Analgesia

10744. Alphaxalone, a neurosteroid anesthetic, inhibits norepinephrine transporter function in cultured bovine adrenal medullary cells. (Abstract)

Alphaxalone, a neurosteroid anesthetic, inhibits norepinephrine transporter function in cultured bovine adrenal medullary cells. We studied the effects of alphaxalone, a neurosteroid anesthetic, on norepinephrine transporter (NET) function in cultured bovine adrenal medullary cells and the effect of a bolus injection of alphaxalone on blood pressure and serum norepinephrine (NE) levels in anesthetized rats. Alphaxalone (10-100 micro M) inhibited the desipramine-sensitive uptake of [(3)H]-NE (...) the desipramine-sensitive uptake of [(3)H]-norepinephrine (NE) by interfering with desipramine binding in bovine adrenal medullary cells. A bolus IV administration of alphaxalone slightly and significantly increased the serum NE levels in anesthetized rats. These findings suggest that alphaxalone competitively inhibits NE transporter function probably in sympathetic neurons.

2002 Anesthesia and Analgesia

10745. Cerebral blood flow is not altered in sheep with Pseudomonas aeruginosa sepsis treated with norepinephrine or nitric oxide synthase inhibition. (Abstract)

Cerebral blood flow is not altered in sheep with Pseudomonas aeruginosa sepsis treated with norepinephrine or nitric oxide synthase inhibition. The origin of cerebral dysfunction in patients with sepsis is still unclear. However, altered cerebral perfusion may play an important role in its pathogenesis. Using an established, chronic model of hyperdynamic ovine sepsis, we examined cerebral perfusion in 20 sheep subjected to a continuous infusion of live Pseudomonas aeruginosa. After 24 h (...) of sepsis, the hypotensive sheep (reduction in mean arterial blood pressure by 16%; P < 0.05) received the nitric oxide synthase inhibitor N(G)-mono-methyl-L-arginine (L-NMMA; 7 mg. kg(-1). h(-1); n = 7), norepinephrine (NE; n = 7), or normal saline (control; n = 6). NE infusion was individually targeted to achieve the same increase in mean arterial blood pressure as that observed in matched sheep of the L-NMMA group. Regional perfusion was measured by using colored microspheres. Although L-NMMA caused

2003 Anesthesia and Analgesia

10746. Intraspinal adenosine induces spinal cord norepinephrine release in spinal nerve-ligated rats but not in normal or sham controls. (Abstract)

Intraspinal adenosine induces spinal cord norepinephrine release in spinal nerve-ligated rats but not in normal or sham controls. Intrathecal adenosine is antinociceptive under conditions of central sensitization, but not in response to acute stimuli in normals. The reasons for this selective circumstance of action remain unclear, but some evidence links adenosine's antinociceptive effects to release of norepinephrine by terminals in the spinal cord. The purpose of this study was to test (...) whether spinal adenosine induces norepinephrine release selectively in settings of hypersensitivity.Rats randomly assigned to spinal nerve ligation, sham operation, or no operation were anesthetized. A microdialysis fiber was implanted in the spinal cord dorsal horn at the L5-L6 level and perfused with artificial cerebrospinal fluid. After washout and a baseline sample period, adenosine at various concentrations was infused through the fiber for 150 min, and samples were collected every 15 min.In

2003 Anesthesiology

10747. Deactivation of norepinephrine by peroxynitrite as a new pathogenesis in the hypotension of septic shock. (Abstract)

Deactivation of norepinephrine by peroxynitrite as a new pathogenesis in the hypotension of septic shock. Vascular hyporeactivity to catecholamines limits successful treatment of hypotension in septic shock. Large amounts of nitric oxide (NO) and superoxide anion (O(2)(-1).) are produced in response to bacterial endotoxins and/or inflammatory cytokines. NO reacts with O(2)(-1). to form the potentially toxic NO metabolite, peroxynitrite (ONOO(-1)). The purpose of this study was to investigate (...) whether ONOO(-1) decreases the vasocontractile activity of norepinephrine.Norepinephrine was treated with ONOO(-1) or 3-morpholinosydonimine-N-ethyl-carbamine (SIN-1; an ONOO(-1) producer) in a 5 x 10(-2) m sodium phosphate buffer solution at pH 7.4, and absorbance of the product was measured spectrophotometrically at 295 and 370 nm. Norepinephrine pretreated with ONOO(-1) was administered to isolated rat thoracic aortas to observe contractions in functional experiments. The rate constant between

2003 Anesthesiology

10748. The sympathomimetic actions of l-ephedrine and d-pseudoephedrine: direct receptor activation or norepinephrine release? (Abstract)

The sympathomimetic actions of l-ephedrine and d-pseudoephedrine: direct receptor activation or norepinephrine release? The basic mechanisms by which ephedrine is preferred over other vasopressors in obstetric anesthesia have not been clearly defined. We examined the sympathomimetic effects of l-ephedrine, currently used as a vasopressor, and d-pseudoephedrine, currently used as a decongestant. In anesthetized rats, l-ephedrine and d-pseudoephedrine caused dose-dependent increases in arterial (...) umbilical artery and vein, the two isomers failed to generate any contraction when given at the concentration that is capable of producing significant effects on anococcygeal and atrial tissues. Although direct adrenoceptor activation with l-ephedrine was detectable at tissue levels, the pressor response in vivo was entirely attributable to norepinephrine release from sympathetic nerves. This indirect mechanism could partly explain why l-ephedrine is better at increasing maternal arterial blood pressure

2003 Anesthesia and Analgesia

10749. Microdialysis study of myocardial norepinephrine during repeated ischemias. 30 mins ischemia inhibits norepinephrine release in rat myocardium during test ischemia Full Text available with Trip Pro

Microdialysis study of myocardial norepinephrine during repeated ischemias. 30 mins ischemia inhibits norepinephrine release in rat myocardium during test ischemia Character of tissue changes as well as their reversibility could vary depending on the duration of myocardial ischemia. Long (over 30 min) ischemia leads to a massive release of myocardial interstitial norepinephrine. We tried to investigate changes in the myocardial sympathetic system produced by a relatively long episode (...) of ischemia-repeperfusion. Myocardial norepinephrine has been collected by means of microdialysis probe during repeated occlusions of the left descending coronary artery. It was shown that long episode of occulusion-reperfusion resulted in suppression of massive norepinephrine release in response to second (test) occlusion. The features of norepinephrine release during successive occlusions make it possible to associate this process with the reversibility of the ischemic tissue damages.

2007 Rossiiskii fiziologicheskii zhurnal imeni I.M. Sechenova / Rossiiskaia akademiia nauk

10750. Cardiac norepinephrine transporter protein expression is inversely correlated to chamber norepinephrine content Full Text available with Trip Pro

Cardiac norepinephrine transporter protein expression is inversely correlated to chamber norepinephrine content The cardiac neuronal norepinephrine (NE) transporter (NET) in sympathetic neurons is responsible for uptake of released NE from the neuroeffector junction. The purpose of this study was to assess the chamber distribution of cardiac NET protein measured using [(3)H]nisoxetine binding in rat heart membranes and to correlate NE content to NET amount. In whole mounts of atria, NET

2008 American Journal of Physiology - Regulatory, Integrative and Comparative Physiology

10751. Effects of norepinephrine and a combined norepinephrine and dobutamine infusion on systemic hemodynamics and indices of renal function in normotensive neonatal thoroughbred foals. (Abstract)

Effects of norepinephrine and a combined norepinephrine and dobutamine infusion on systemic hemodynamics and indices of renal function in normotensive neonatal thoroughbred foals. Norepinephrine is a potent vasopressor that increases arterial blood pressure but may have adverse effects on renal blood flow. The combination of norepinephrine and dobutamine may lead to improved renal perfusion compared to an infusion of norepinephrine alone. The effects of these drugs in the normotensive neonatal (...) foal have not been reported.Norepinephrine increases arterial blood pressure. Adding dobutamine to a norepinephrine infusion will change the renal profile during the infusions without changing the arterial blood pressure.Eight conscious Thoroughbred foals were used in this study.Each foal received norepinephrine (0.1 microg/kg/min), combined norepinephrine (0.1 microg/kg/min) and dobutamine (5 microg/kg/min), and a control dose of saline in a masked, placebo-controlled study. Heart rate, arterial

2006 Journal of veterinary internal medicine / American College of Veterinary Internal Medicine Controlled trial quality: uncertain

10752. Effects of norepinephrine and combined norepinephrine and fenoldopam infusion on systemic hemodynamics and indices of renal function in normotensive neonatal foals. Full Text available with Trip Pro

Effects of norepinephrine and combined norepinephrine and fenoldopam infusion on systemic hemodynamics and indices of renal function in normotensive neonatal foals. Norepinephrine increases arterial blood pressure but may have adverse effects on renal blood flow. Fenoldopam, a dopamine-1 receptor agonist, increases urine output in normotensive foals. The combination of norepinephrine and fenoldopam may lead to improved renal perfusion compared with an infusion of norepinephrine alone (...) . The combined effects of these drugs have not been reported in the horse.Norepinephrine will alter the hemodynamic profile of foals without affecting renal function. Addition of fenoldopam will change the renal profile during the infusions without changing the hemodynamic profile.Five conscious pony foals.Each foal received norepinephrine (0.3 microg/kg/min), combined norepinephrine (0.3 microg/kg/min) and fenoldopam (0.04 microg/kg/min), and a control dose of saline in a masked, placebo-controlled study

2008 Journal of veterinary internal medicine / American College of Veterinary Internal Medicine

10753. Effect of music on perceived exertion, plasma lactate, norepinephrine and cardiovascular hemodynamics during treadmill running. (Abstract)

Effect of music on perceived exertion, plasma lactate, norepinephrine and cardiovascular hemodynamics during treadmill running. We examined the effects of listening to headphone music in ten well trained men (25.1 +/- 6 years) during treadmill running. Maximal oxygen consumption, determined by open circuit spirometry, was followed by two submaximal work bouts 72 hours apart. The work bouts consisted of a supine rest, a 15 minute run at 70% of maximal oxygen consumption, and a three minute (...) active recovery period. Participants listened to music during one of the two trials. Hemodynamic variables and perceived exertion were recorded at three minute intervals during each trial. A venous blood sample, obtained prior to and following each trial, was assayed for norepinephrine and plasma lactate. Analysis of variance revealed significant differences (p < 0.05) between the no music versus the exercise with music trial for (aggregate data 3,6,9,12,15 minutes): heart rate 152.9 +/- 5.3 to 145.9

1998 International Journal of Sports Medicine

10754. Modulation of the effects of norepinephrine uptake inhibitors on the norepinephrine-induced contractile response of the porcine uterine artery during early pregnancy. Full Text available with Trip Pro

Modulation of the effects of norepinephrine uptake inhibitors on the norepinephrine-induced contractile response of the porcine uterine artery during early pregnancy. The effects of norepinephrine (NE) uptake inhibitors on the porcine uterine artery's contractile response to NE and their potential alteration during early pregnancy (Day 13 postcoitus; day of coitus = Day 0) in comparison with the end of the luteal phase (Days 11-14; first day of behavioral estrus = Day 0) was investigated

1997 Canadian Journal of Veterinary Research

10755. The differential effects of circulating norepinephrine and neuronally released norepinephrine on sodium excretion in humans. (Abstract)

The differential effects of circulating norepinephrine and neuronally released norepinephrine on sodium excretion in humans. The renal effects of incremental infusions of norepinephrine (placebo, 0.025 mu/kg/min), 0.075 micrograms/kg/min, phenylephrine (placebo, 0.5 micrograms/kg/min, 2.5 micrograms/kg/min), and tyramine (placebo, 2 micrograms/kg/min, 15 micrograms/kg/min) were examined in three respective groups (n = 9, 8, and 8) of normotensive male subjects undergoing water diuresis (...) . Tyramine is an indirect sympathetic agent that causes neuronal release of endogenous norepinephrine. Increases in mean arterial pressure during each high-dose infusion were comparable in all three groups. Both norepinephrine and phenylephrine caused a decrease in urinary sodium excretion and effective renal plasma flow, with no changes in glomerular filtration rate. Proximal tubular sodium reabsorption, as assessed by both lithium clearance and solute-free water clearance methods, was increased

1993 Clinical pharmacology and therapeutics

10756. Effects of epinephrine, norepinephrine, or the combination of norepinephrine and dobutamine on gastric mucosa in septic shock. (Abstract)

Effects of epinephrine, norepinephrine, or the combination of norepinephrine and dobutamine on gastric mucosa in septic shock. To compare in the same patient with septic shock, respective effects of epinephrine, norepinephrine, and the combination of norepinephrine and dobutamine (5 microg/kg/min) on systemic hemodynamic parameters and gastric mucosal perfusion using gastric tonometry and laser-Doppler flowmetry techniques.Prospective, controlled, randomized, crossover study.University hospital (...) intensive care unit.Twelve patients with septic shock.Each patient received in a random succession epinephrine, norepinephrine, and norepinephrine plus dobutamine. Dosages of epinephrine and norepinephrine were adjusted to achieve a mean arterial pressure between 70 and 80 mm Hg. A laser-Doppler probe and a tonometer were introduced into the gastric lumen.The increase in gastric mucosal perfusion detected by laser-Doppler flowmetry was higher with epinephrine and the combination of norepinephrine

1999 Critical care medicine Controlled trial quality: uncertain

10757. Estrogen supplementation decreases norepinephrine-induced vasoconstriction and total body norepinephrine spillover in perimenopausal women. (Abstract)

Estrogen supplementation decreases norepinephrine-induced vasoconstriction and total body norepinephrine spillover in perimenopausal women. Estrogens are reported to provide protection against the development of cardiovascular disease in women, but the mechanisms underlying these effects are not well defined. We hypothesized that estrogen might reduce neural cardiovascular tone. We therefore studied responses to exogenous norepinephrine and norepinephrine spillover in 12 perimenopausal women (...) randomized to 8 weeks of estrogen supplementation (estradiol valerate, 2 mg daily, n=7) or placebo (n=5). Forearm blood flow was measured by venous occlusion plethysmography, and vasoactive agents were infused through a brachial artery cannula in doses that did not influence blood pressure or heart rate. Total body and forearm norepinephrine spillover were measured by radiotracer methodology. Forearm vasoconstrictor responses to norepinephrine (25, 50, and 100 ng/min) were attenuated after estrogen

1997 Hypertension Controlled trial quality: uncertain

10758. Effects of norepinephrine, epinephrine, and norepinephrine-dobutamine on systemic and gastric mucosal oxygenation in septic shock. (Abstract)

Effects of norepinephrine, epinephrine, and norepinephrine-dobutamine on systemic and gastric mucosal oxygenation in septic shock. To compare the effects of dopamine, norepinephrine, epinephrine, and the combination of norepinephrine and dobutamine on systemic and gastric mucosal oxygen metabolism in patients with septic shock.Sixteen patients with septic shock were enrolled in the present study. Each patient received dopamine firstly, then in a random succession epinephrine, norepinephrine (...) , or norepinephrine-dobutamine, a mean systemic arterial pressure adjusted to >9.31 kPa. After 120 min of each treatment, hemodynamic, oxygen metabolic, and gastric mucosal parameters were obtained.Epinephrine induced a significant increase in heart rate compared with other three groups (P <0.05), and a significant higher cardiac index compared with norepinephrine alone and norepinephrine-dobutamine (P <0.05). Oxygen extraction ratio values were lower with epinephrine infusion as compared with other three groups

2002 Acta pharmacologica Sinica Controlled trial quality: uncertain

10759. Plasma l-[3H]norepinephrine, d-[14C]norepinephrine, and d,l-[3H]isoproterenol kinetics in essential hypertension. Full Text available with Trip Pro

Plasma l-[3H]norepinephrine, d-[14C]norepinephrine, and d,l-[3H]isoproterenol kinetics in essential hypertension. We infused tracer-labeled l-[3H]-norepinephrine, d-[14C]norepinephrine, and d,l-[3H]-isoproterenol simultaneously into patients with essential hypertension and into normotensive control subjects, in order to determine whether abnormalities in the disappearance kinetics of these substances characterized the hypertensive patients. The mean preinfusion venous plasma norepinephrine (...) concentration was somewhat higher in the hypertensive group (260 vs. 194 pg/ml, P = 0.06), but the groups did not differ in the disappearance kinetics of l- or d-norepinephrine or of isoproterenol. Preinfusion plasma norepinephrine was significantly positively correlated with calculated spillover rates in both the hypertensive and normotensive groups, but not with norepinephrine clearances. The d/l ratio in plasma norepinephrine was the same as in the infusate during and after the infusion, even after

1983 Journal of Clinical Investigation

10760. Effects of norepinephrine alone and norepinephrine plus dopamine on human intestinal mucosal perfusion. (Abstract)

Effects of norepinephrine alone and norepinephrine plus dopamine on human intestinal mucosal perfusion. To evaluate the effect of norepinephrine alone and norepinephrine combined with dopamine on jejunal mucosal perfusion, gastric-arterial pCO(2) gradient, and global splanchnic oxygen demand-supply relationship after cardiac surgery.A prospective interventional study.A university cardiothoracic intensive care unit.Eighteen patients were studied during propofol sedation and mechanical (...) ventilation after uncomplicated coronary artery bypass surgery.After control measurements, each patient received norepinephrine (50+/-26 ng.kg.min) to increase mean arterial blood pressure by 30% followed by addition of low-dose dopamine (2.6+/-0.3 microg x kg x min). Postdrug control measurements were performed 120 min after discontinuation of the catecholamines.Norepinephrine induced a 32% increase in systemic vascular resistance with no change in cardiac index. Neither jejunal mucosal perfusion

2003 Intensive Care Medicine

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