Urinary Norepinephrine Concentrations Research Articles

Norepinephrine augmented in vitro growth of uropathogenic E. coli in Type 2 diabetes mellitus and its suppression by silodosin (alpha blocker)

Norepinephrine is secreted under conditions of stress in humans. The ability of bacteria to sense mammalian hormone may have a role in propagation of infection. The present study investigated the effect of norepinephrine on in vitro growth of uropathogenic E. coli (UPEC) and the effect of silodosin on norepinephrine-induced changes. The spot urine samples were collected from 56 individuals (14 diabetic patients with UTI, 14 diabetic without UTI, 14 non-diabetic UTI and 14 healthy volunteer controls) for the measurement of urinary norepinephrine concentrations. The concentration of norepinephrine, as found in urine of human subjects, was reproduced in artificial urine medium to study the growth of UPEC. The norepinephrine concentration showing maximum growth response was selected to study the effect of silodosin on the growth inhibition of UPEC. Result showed significantly elevated urinary norepinephrine in diabetic patients with and without UTI and also in nondiabetic UTI groups. The norepinephrine concentration equivalent to that in diabetic UTI patients enhanced the growth of UPEC. Furthermore, silodosin (0.32 μM) inhibited the growth of the UPEC.

Abstract 536: Resiniferatoxin-induced Disorders in Glucose Homeostasis and Hypertension: Role of Trpv1-positive Sensory Nerves

Resiniferatoxin (RTX), an ultrapotent agonist of the transient receptor potential vanilloid 1 (TRPV1) channels, has been used to relieve pain in humans in clinical trials that are ongoing, completed, or terminated due to its unwanted side effects that have not been well understood. We test the hypothesis that RTX causes disorders in glucose homeostasis, renal functional and structural impairment, and hypertension via insulin receptor-mediated increases in sympathetic nerve activity. Male Wistar rats were injected with RTX (0.2 mg/kg, i.p.) or vehicle. Pancreatic and renal TRPV1 levels were decreased 4 weeks after RTX treatment, confirming effective and lasting treatment of RTX (p<0.05). RTX decreased plasma insulin levels (Control: 1.4±0.1 vs RTX: 0.8±0.1 ng/ml, p<0.05) but improved glucose tolerance (p<0.05). RTX increased the translocation of skeletal muscle glucose transporter 4 (Glut4) from cytosol to cell membrane indicated by increased membrane fraction but decreased cytosol fraction of Glut4 in RTX-treated rats (p<0.05). RTX increased levels of phosphorylated insulin receptor substrate 1 in sympathetic ganglia (Control: 0.43±0.04 vs RTX: 0.65±0.08, p<0.05), renal tyrosine hydroxylase contents, and urinary norepinephrine concentrations (Control: 352±70 vs RTX: 781±142 ng/day, p<0.05). When TRPV1 expressed in sensory neurons and their nerve endings innervating the kidney was knocked down by intrathecal (i.t) injection of TRPV1 shRNA, insulin (3nmol/kg, i.t.)-induced increases in efferent renal nerve activity were further enhanced (Control: 40±3 vs TRPV1 shRNA: 53±2, p<0.05). RTX decreased creatinine clearance (Control: 0.58±0.04 vs RTX: 0.46±0.04 ml/min/100 gbwt, p<0.05) and increased levels of plasma urea, urinary albumin, renal connective tissue growth factor, and systolic blood pressure (Control: 128±1 vs RTX: 143±2 mmHg, p<0.05). Thus, RTX treatment causes disorders in glucose homeostasis, renal functional and structural impairment, and hypertension, possibly via increasing sympathetic nerve activity resulting from enhanced stimulatory effects of the insulin receptors expressed in sympathetic nerves and weakened inhibitory effects of TRPV1-positive sensory nerves on sympathetic nerves.

Activation of Central Angiotensin Type 2 Receptors Suppresses Norepinephrine Excretion and Blood Pressure in Conscious Rats

We have previously documented the finding that central angiotensin type 2 receptors (AT2R) negatively modulate sympathetic outflow and arterial blood pressure (BP). In this study, we investigated the effects of intracerebroventricular (icv) infusion of Compound 21 (C21), the first selective nonpeptide AT2R agonist, on norepinephrine (NE) excretion and BP in rats. C21 was infused icv for 7 days, using a micro-osmotic pump. Urinary NE concentration was measured using the NE enzyme immunoassay kit. BP was recorded by radiotelemetry. After 7 days, the rats were killed and three relevant samples from sympathetic brain regions and the cerebral cortex were obtained by micro-punching to measure neuronal nitric oxide synthase (nNOS) protein expression by western blot. In addition, the influence of C21 on neuronal potassium current (I(Kv)) was determined by whole-cell patch-clamp in a neuron cell line, CATH.a. (i) Icv treatment with C21 significantly decreased both the concentration and the amount of NE in night time urine, but had no effect on daytime urine. (ii) C21-treated rats exhibited a slight but significant decrease in BP. (iii) The effects of C21 on NE excretion and BP were abolished by use of the AT2R antagonist, PD123319, and nitric oxide synthase (NOS) inhibitor, N-omega-nitro-L-arginine methyl ester (L-NAME). (iv) C21 treatment significantly upregulated nNOS expression in the paraventricular nucleus of the hypothalamus (PVN) and rostral ventrolateral medulla (RVLM), but not in the nucleus of the solitary tract (NTS) and cerebral cortex. (v) In CATH.a neurons, C21 treatment significantly increased I(Kv), and this increase was completely abolished by PD123319 and L-NAME. These results demonstrate a central inhibitory influence of C21 on sympathetic outflow by means of a nNOS-dependent mechanism that might be mediated by facilitating the neuronal potassium channel.

Catecholamine alterations in pediatric obstructive sleep apnea: Effect of obesity

Obstructive sleep apnea (OSA) elicits increased sympathetic activity in adults and increased urinary catecholamines. Moreover, urinary catecholamine excretion is altered in obese patients. We hypothesized that morning urine catecholamine levels would be correlated with the severity of obstructive sleep apnea and degree of obesity in children. Children referred to the pediatric sleep center for habitual snoring underwent overnight polysomnography, and the first morning voided urine sample was collected. Urinary concentrations of norepinephrine, epinephrine and dopamine were measured and corrected for creatinine levels. In a subset of children, blood samples were drawn and gene expression of catecholamine-relevant genes analyzed by quantitative real-time PCR. One hundred fifty-nine children were recruited and completed the protocol. Children with OSA had significantly higher urinary norepinephrine and epinephrine levels, but not dopamine, compared to habitual snorers (norepinephrine: 40.1 +/- 24.7 ng/mg creatinine vs. 31.6 +/- 16.2 ng/mg creatinine, P < 0.01; epinephrine: 6.4 +/- 10.5 ng/mg vs. 4.5 +/- 0.5 ng/mg, P < 0.01). There was a positive correlation between norepinephrine and epinephrine values and polysomnographic indices, but no effect of obesity on catecholamine levels. In addition, expression of several of the major genes involved in synthesis and transport of catecholamines, as well as in selected receptors were compatible with increased bioavailability of catecholamines. In children with OSA, morning urinary norepinephrine and epinephrine levels are significantly higher than those without OSA, and correlate with the severity of the disease. Gene expression patterns are in agreement with such findings. Urine catecholamine levels do not appear to be influenced by the presence of obesity. Thus, altered sympathetic activity in OSA patients appears to occur independently of the presence of obesity.

Validation of a behavioral observation tool to assess pig welfare

Accurately measuring and monitoring of animal behavior is an important factor when assessing on-farm animal welfare. First we developed a feasible and simple method aiming at consistently on-farm measuring of pig's behavior. This test should cover a broad range of welfare-related pig behavior. The reaction towards a novel object, startling, tail and ear biting, play and aggressive behavior, stereotypies, coughing, sneezing, skin lesions, defecation, urination and cleanliness of body and pen are included. The development of accurate measures of on-farm behavior first requires the reliability assessment of the procedure. Therefore, the methodology was tested in a first part by three observers scoring simultaneously and independently pre-defined behavioral characteristics of 108 group-housed fattening pigs. The inter-observer repeatability of the measures was calculated using intraclass correlation coefficients, which ranged from 0.7 to 1. In a second part, the objective was to validate the behavioral characteristics against salivary cortisol, urinary epinephrine and norepinephrine and production traits. Salivary cortisol concentrations significantly increased in ear-bitten pigs and in pigs with tail lesions. Growth rate significantly dropped when cortisol levels rose. An age effect was also found. The percentage of animals approaching the novel object is positively correlated with the urinary epinephrine concentration. Pigs defecating during the test showed significantly higher epinephrine levels. Urinary norepinephrine concentration decreased significantly with age. Faster growing animals and animals with tail lesions showed significantly higher levels of norepinephrine. Pen dirtiness and number of animals per pen were associated with higher norepinephrine concentrations. Finally, barrows had higher norepinephrine concentrations than sows.

The Alternative Stimulatory G Protein α-Subunit XLαs Is a Critical Regulator of Energy and Glucose Metabolism and Sympathetic Nerve Activity in Adult Mice

The complex imprinted Gnas locus encodes several gene products including G(s)alpha, the ubiquitously expressed G protein alpha-subunit required for receptor-stimulated cAMP generation, and the neuroendocrine-specific G(s)alpha isoform XLalphas. XLalphas is only expressed from the paternal allele, whereas G(s)alpha is biallelically expressed in most tissues. XLalphas knock-out mice (Gnasxl(m+/p-)) have poor suckling and perinatal lethality, implicating XLalphas as critical for postnatal feeding. We have now examined the metabolic phenotype of adult Gnasxl(m+/p-) mice. Gnasxl(m+/p-) mice had reduced fat mass and lipid accumulation in adipose tissue, with increased food intake and metabolic rates. Gene expression profiling was consistent with increased lipid metabolism in adipose tissue. These changes likely result from increased sympathetic nervous system activity rather than adipose cell-autonomous effects, as we found that XLalphas is not normally expressed in adult adipose tissue, and Gnasxl(m+/p-) mice had increased urinary norepinephrine levels but not increased metabolic responsiveness to a beta3-adrenergic agonist. Gnasxl(m+/p-) mice were hypolipidemic and had increased glucose tolerance and insulin sensitivity. The similar metabolic profile observed in some prior paternal Gnas knock-out models results from XLalphas deficiency (or deficiency of the related alternative truncated protein XLN1). XLalphas (or XLN1) is a negative regulator of sympathetic nervous system activity in mice.

Contributions of hypoxia and respiratory disturbance index to sympathetic activation and blood pressure in obstructive sleep apnea syndrome

Hypertension is a common finding among obstructive sleep apnea (OSA) patients, and is thought to be caused by sympathetic hyperactivity. The present study compares the contributions of the respiratory disturbance index (RDI) as a reflection of sleep fragmentation, and the magnitude of oxygen desaturation, to sympathetic activation as indexed by urinary norepinephrine concentrations, as well as to morning and evening blood pressure in sleep apnea syndrome patients. Data (polysomnography, blood pressure [BP], and urine catecholamines) of 38 consecutive OSA patients (age, 46 ± 14.5 years) were analyzed. Stepwise logistic regression analysis revealed that minimal oxygen saturation level (SaO 2min) was a significant predictor of both morning and evening norepinephrine levels, and that 37% of morning systolic BP variance could be accounted for by a combination of age and norepinephrine, while 20% of the diastolic BP variance was accounted for by SaO 2min alone. In contrast, RDI entered the prediction equation only when minimal oxygen saturation was rejected first. Our results indicate that the degree of nocturnal hypoxia is more closely associated with the level of sympathetic activation and with daytime level of blood pressure than with sleep fragmentation.

Effect of overeating on plasma and urinary concentrations of norepinephrine.

This study examined the effect of overeating on plasma norepinephrine concentrations and urinary norepinephrine excretion in man, since overeating sucrose or fat increases norepinephrine turnover in rodents. Five normal subjects were overfed by 50% for 20 days, without substantially changing the proportions of protein, fat, and carbohydrate in the diet, after a control period of normal feeding. Sodium intake remained constant throughout the study. There was no effect of overfeeding on plasma norepinephrine concentrations when subjects were resting supine either before or after a meal. However, plasma norepinephrine concentrations after 10 min of orthostasis were 40% lower (P less than 0.05) at the end of overfeeding. Plasma norepinephrine concentrations during slow walking also tended to be lower during overfeeding, but this effect was not statistically significant. Mean 24-h norepinephrine and epinephrine excretion were not altered. These data do not support the hypothesis that overeating increases sympathetic nervous system activity in man.

Cardiovascular, Humoral, and Renal Effects of Phenoxybenzamine in Hypertension

We examined the effects of alpha adrenergic receptor blockade with phenoxybenzamine on various parameters related to blood pressure regulation in 10 normotensive and 12 essential hypertensive subjects. The responses were observed before and after phenoxybenzamine treatment during standardized maneuvers of volume expansion with saline infusion and volume contraction with a diuretic. Alpha adrenergic blockade produced a significantly greater (P less than 0.02) reduction in blood pressure in the hypertensive group than in the normotensive subjects. The baroreceptor response, evaluated by comparing the change in plasma norepinephrine concentration in relation to the change in blood pressure, was significantly reduced (P less than 0.05) in hypertensives compared to normal subjects. Plasma and urinary norepinephrine concentration, which were similar in the two groups, increased in both during phenoxybenzamine treatment. There was no significant change in the mean levels of plasma renin activity or plasma aldosterone concentration in either group after phenoxybenzamine treatment. However, the relationship between plasma renin activity and plasma aldosterone levels, as judged by linear regression analysis, was significantly altered (P less than 0.05) by phenoxybenzamine therapy in both groups. The latter may reflect an effect of phenoxybenzamine on the metabolism or secretion of aldosterone. These results, utilizing an alpha adrenergic antagonist, confirm the enhanced vascular reactivity and diminished baroreceptor function in essential hypertension; no evidence for an alpha adrenergic effect on plasma renin activity could be demonstrated in normotensive or hypertensive subjects.

The renin-angiotensin-aldosterone system and hypertension in primary hyperparathyroidism

To evaluate the role of the renin-angiotensin-aldosterone system in the hypertension associated with primary hyperparathyroidism, we measured plasma renin activity and aldosterone concentration before and after maneuvers to suppress and stimulate this system in 11 hypertensive patients with primary hyperparathyroidism. We also measured plasma or urinary norepinephrine concentration to examine the role of catecholamines in the hypertension. The results were compared with an age- and race-matched control population. While the mean plasma aldosterone concentrations were normal, the mean plasma renin activity in response to furosemide stimulation was subnormal in subjects with hyperparathyroidism. Plasma or urinary norepinephrine concentrations were within the normal range. Thus a specific abnormality of the renin-angiotensin-aldosterone system or catecholamines could not be identified in these hypertensives with primary hyperparathyroidism.

Sodium-neural interactions in the development of spontaneous hypertension.

The influence of alterations in sodium intake on blood pressure and indices of peripheral sympathetic activity was studied during the development of hypertension in the SHR. Male SHRs were given a diet containing either low (0.05%), normal (0.29%) or high (3.4%) sodium content beginning at 7 weeks of age. Systolic blood pressure was measured weekly by the tail cuff method in conscious animals. Three weeks after initiation of the diets 24 hour urines were collected for analysis of catecholamines. Plasma catecholamines were measured and the blood pressure response to ganglionic blockade (hexamethonium bromide, 30 mgm/kg) determined. High sodium resulted in a marked increase in the severity of hypertension that was associated with an increase in plasma and urinary norepinephrine concentration and an exaggerated depressor response to ganglionic blockade. In addition, a highly significant positive correlation was seen between plasma norepinephrine concentration and systolic blood pressure. The results are compatible with the hypothesis that the increase in blood pressure in the SHR maintained on a high sodium intake is in part due to an increase in peripheral sympathetic activity.

Ultrastructural and biochemical evaluation of adrenal medullary hyperplasia and pheochromocytoma in aged bulls.

Pheochromocytomas and adrenal medullary hyperplasia were investigated ultrastructurally and by assaying catecholamines in tissue and urine. Three of seven bulls had concomitant thyroid C-cell neoplasms and normal parathyroid glands. Pheochromocytomas were either bilateral or unilateral, and were composed of large chromaffin cells predominantly in the storage phase of the secretory cycle. Two pheochromocytomas were composed of cells with ultrastructural characteristics of the epinephrine-secreting type and contained round secretory granules of low electron density. The norepinephrine-secreting type of chromaffin cell predominated in one pheochromocytoma and had storage granules with an electron-dense, eccentric core and a wide submembranous space. Two pheochromocytomas were composed of a mixture of epinephrine- and norepinephrine-secreting cells. Adrenal medullary hyperplasia in four bulls consisted of multinodular or diffuse areas of hyperchromatic chromaffin cells that were non-encapsulated, and compressed adjacent cortical tissue. Tissue and urinary concentrations of norepinephrine were increased in bulls with adrenal medullary hyperplasia or pheochromocytoma, but urinary vanillylmandelic acid and unconjugated epinephrine levels were not different from those of control bulls with a normal adrenal medulla.

Alterations in Motor Activity, Sleep, and Biochemistry in a Cycling Manic-Depressive Patient

Biochemical and electrophysiological factors were studied longitudinally in a rapidly cycling manic-depressive patient. Slow changes in mood, motor activity, sleep, and urinary norepinephrine levels during the course of each depressed and manic episode are reported, as well as rapid alterations in many variables at the time of mood switch. Urinary concentrations of norepinephrine and its metabolite, 3-methoxy-4-hydroxyphenyl glycol (MHPG) were significantly lower in depression than in mania; norepinephrine but not MHPG excretion increased prior to the switch. We postulate that the slow behavioral and biological changes preceding switches in this patient are an important manifestation of the cyclic process in manic-depressive illness.

The effects of morphine and halothane anaesthesia on urine norepinephrine during and after coronary artery surgery.

Urine concentrations and excretion rates of norepinephrine were measured in 28 patients anaesthetized with halothane or morphine before, during and for two hours after aortocoronary artery grafting procedures. All patients were paralyzed with d-tubocurarine, intubated and respiration was controlled. Urine was obtained for 90 minutes before induction, during induction, before, during and after bypass and postoperatively. In patients anaesthetized with halothane, urinary norepinephrine concentrations and excretion rates were not significantly different from preoperative values until the postoperative period. Patients anaesthetized with morphine did not have urine norepinephrine concentrations different from preoperative values until bypass, when they became significantly increased. All subsequent urine norepinephrine concentrations and excretion rates were significantly elevated when compared to preoperative values. These findings do not indicate a mechanism but they do demonstrate that morphine anaesthesia is associated with increased urinary and probably also increased plasma levels of norepinephrine during and after cardiopulmonary bypass in patients undergoing coronary artery operations.

Fluorometric estimation of epinephrine and norepinephrine.

The fluorometric method of Lund for the quantitative detection of B-catechol ethanolamines is examined and modified. Reliable application of this method to the assay of epinephrine and norepinephrine in urine and plasma was achieved only after careful selection of reagents and conditions during the analysis. Though epinephrine was relatively stable in plasma and urine, urinary norepinephrine concentrations increased significantly when the urine was stored for several days. Submitted on October 30, 1957