Urinary Norepinephrine Excretion Research Articles

A case of ischemic colitis associated with pheochromocytoma

A 40-year old woman was admitted because of abdominal pain and diarrhea. She sometimes experienced paroxysmal hypertension, sweating, headache, and palpitation. Sigmoidoscopic findings showed well-demarcated diffuse mucosal edema, hyperemia, and easy touch bleeding from distal descending colon up to the splenic flexure area. Barium x-ray showed loss of haustral marking, thumb printing appearance, and diffuse luminal stenosis in the transverse, descending, and sigmoid colon. On the abdominal computed tomogram, a 3.8-cm sized well-enhanced right adrenal mass was incidentally found. Twenty-four hour urinary excretion of vanillyl mandelic acid, norepinephrine, and normetanephrine were increased. Iodine 131 metaiodobenzylguanidine scan showed hot uptake on the right adrenal gland compatible with pheochromocytoma. Exploratory laparotomy was done under the impression of ischemic colitis associated with pheochromocytoma. Adrenalectomy and resection of the stenotic left colon were performed. After surgery, pain subsided, blood pressure fell gradually, blood sugar and catecholmaine level became

Urinary excretion of catecholamines in hospitalized and non-hospitalized healthy children and adolescents

Non-conjugated catecholamines were measured in morning urine samples from 111 healthy, non-hospitalized subjects aged 8-18 y and in 16 hospitalized, healthy subjects aged 12-16 y. The catecholamines were extracted by cation exchange columns and alumina adsorption and quantitated with HPLC with electrochemical detection. The concentration of catecholamines was related both to the urinary creatinine concentration and to the collecting period and body surface area. Linear regression analysis was used to estimate continuous age-related reference centiles based upon the measurements from the 111 non-hospitalized subjects. The upper limits for the adrenaline/creatinine and noradrenaline/creatinine ratios were lower than in previous studies. The excretion of adrenaline and noradrenaline per hour and m2 body surface area was higher in the 16 hospitalized than in the 74 age-matched non-hospitalized subjects. The excretion of the catecholamines expressed per hour and m2 body surface area and expressed relative to creatinine excretion, decreased with increasing age, and the excretion of adrenaline and noradrenaline per hour and m2 body surface area was higher in boys than in girls. In conclusion, standardization of urine sampling leads to more narrow ranges for urinary adrenaline and noradrenaline excretion in healthy children and adolescents.

Bulbospinal serotonergic activity during changes in thyroid status.

A three-part study explored the basis for an interaction between changes in thyroid status and bulbospinal serotonin (5HT) metabolism. In experiment 1, three well-characterized models of primary hypothyroidism were all accompanied by significant increases in 5HT metabolism. In experiment 2, circulating thyroid hormone levels were experimentally varied from very low methimazole (Meth) treatment to very high (T3 implants: 2.5, 5.0, or 7.5 mg triiodothyronine). As in experiment 1, Meth led to elevated 5HT. Hyperthyroidism was accompanied by significant reductions in 5HT, while urinary norepinephrine excretion paralleled 5HT. In experiment 3, rats were subjected to Meth either 2 weeks before or after induction of diabetes with streptozotocin (Stz). Meth prevented Stz-associated reductions in 5HT and attenuated development of hyperphagia. Meth could not reverse established Stz-associated reduction in 5HT or hyperphagia, although both were slightly attenuated. Thus, although the first two experiments argue for a simple inverse relationship between circulating thyroid hormone levels and 5HT in the brain, experiment 3 demonstrated that Stz-associated decrements in 5HT could not be reversed by subsequent lowering of circulating thyroid hormone. Nor did accompanying measurements indicate that glycemic status or circulating levels of leptin were important predictors of 5HT. Thus the interaction between thyroid hormones and 5HT is both more subtle and more complex than previously thought.

Hormonal, immunological, and hematological responses to intensified training in elite swimmers.

The purpose of this study was to compare the responses of selected hormonal, immunological, and hematological variables in athletes showing symptoms of overreaching with these variables in well-trained athletes during intensified training. Training volume was progressively increased over 4 wk in 24 elite swimmers (8 male, 16 female); symptoms of overreaching were identified in eight swimmers based on decrements in swim performance, persistent high ratings of fatigue, and comments in log books indicating poor adaptation to the increased training. Urinary excretion of norepinephrine was significantly lower (P < 0.05, post hoc analysis) in overreached (OR) compared with well-trained (WT) swimmers throughout the 4 wk. There were no significant differences between OR and WT swimmers for other variables including: concentrations of plasma norepinephrine, cortisol, and testosterone, and the testosterone/cortisol ratio; peripheral blood leukocyte and differential counts, neutrophil/lymphocyte ratio, and CD4/CD8 cell ratio; serum ferritin and blood hemoglobin concentrations, erythrocyte number, hematocrit, and mean red cell volume (MCV). MCV increased significantly over the 4 wk in both groups, suggesting increased red blood cell turnover. These data show that, of the 16 hormonal, immunological, and hematological variables measured, urinary norepinephrine excretion appears to be the only one to distinguish OR from WT swimmers during short-term intensified training. Low urinary norepinephrine excretion was observed 2 to 4 wk before the appearance of symptoms of overreaching, suggesting the possibility that neuroendocrine changes may precede, and possibly contribute to, development of the overreaching/overtraining syndromes.

A prospective study of psychosocial stress and fertility in women.

The objective of this study was to compare average stress levels during the month of conception to those of previous infertile months. We postulated that stress level during the actual month of conception would be lower than that during previous non-conception cycles. Thirteen normal women from the general community, who were attempting pregnancy, kept daily records of coital activity and basal body temperature, and twice a month completed self-administered questionnaires and provided a 12 h overnight urine sample. On average, women reported significantly more favourable mood states on standard psychometric tests, during the month of conception than during the previous non-conception cycles. In addition, they felt significantly less 'hassled' during the month of conception. However, mean urinary hormone excretion of adrenaline, noradrenaline and cortisol did not significantly differ between conception and non-conception cycles and there was little relationship between the psychological measures of mood state and excretion of adrenaline and cortisol. There was no evidence of increased coital frequency during the month of conception when mood states were improved, suggesting that stress effects on libido were unlikely to account for the findings. The results support the conclusion that psychosocial stress influences fertility in females but as yet mechanisms remain unclear.

Hypertension and Abnormalities of Carbohydrate Metabolism Possible Role of the Sympathetic Nervous System

To investigate the relationships between the sympathetic nervous system (SNS) and parameters of glucose metabolism in arterial hypertension, daily urinary excretion of catecholamines and plasma glucose, insulin, and C-peptide response to an oral glucose load (OGL) have been evaluated in 77 untreated patients with mild-to-moderate essential hypertension and in 31 normotensive controls. Urinary excretion of norepinephrine (UNE) was positively correlated with body mass index and with plasma glucose levels both at fast and after OGL. No correlations were found between urinary excretion of catecholamines and plasma insulin and C-peptide levels both at fast and in response to OGL. Because the frequency distribution of UNE was bimodal, hypertensive subjects were separated into two subgroups using an arbitrary cutoff, and the parameters of glucose metabolism were compared. Subjects with UNE > 205 μg/day had greater levels of fasting glucose and greater glycemic response to OGL than subjects with UNE < 205 μg/day, whereas no significant differences between the groups were found in fasting and stimulated plasma insulin and C-peptide. Thus, activation of SNS is related to glucose tolerance but not hyperinsulinemia and insulin hypersecretion in essential hypertension. Plasma glucose levels, independent of insulin, may contribute to the relationship between SNS activity and blood pressure in essential hypertension.

Effects of norepinephrine infusion and exercise on blood pressure in rats.

Two experiments were conducted to test the hypotheses that norepinephrine (NE) infusion would increase blood pressure and wheel running activity level, and, secondly, that voluntary exercise would lower NE-induced increases in blood pressure. NE-bitartrate was infused into male Sprague-Dawley rats using an implanted osmotic pump (3.75 micrograms/kg/min in 0.9% saline). Control rats received the vehicle solution. Systolic blood pressure was measured by the tail-cuff method. Voluntary wheel running activity expressed as wheel revolutions per 24 hr was measured on the 5th, 9th, and 13th day. Blood pressure on the 13th day and wheel running activity on the 9th day were significantly higher in NE-infused rats. The NE content of heart tissue was not altered, but urinary excretion of NE and epinephrine was increased in the NE-infused animals. Food intake, body weight gain, and kidney weight per 100 g body wt were not changed but heart weight per 100 g body wt was increased by NE infusion. Urinary total calcium excretion was higher in the NE-infused rats. Spontaneous voluntary exercise in running wheels attenuated increases of blood pressure in NE-infused rats. The results of the present study suggest that rats receiving exogenous NE exhibit increased blood pressure and voluntary wheel running activity. Voluntary wheel running exercise also reduces blood pressure in NE-infused rats.

Antihypertensive and vasculo- and renoprotective effects of pioglitazone in genetically obese diabetic rats.

Although an improvement of insulin sensitivity has been shown to be a new therapeutic approach for treating diabetes mellitus, details of effects of this treatment on the cardiovascular system and possible renal complications remain unknown. In the present study, we investigated the effects of a thiazolidine derivative, pioglitazone, and examined the insulin-sensitizing action on blood pressure, nephropathy, and vascular changes in genetically obese diabetic Wistar fatty (WF) rats. Pioglitazone (3 mg.kg-1.day-1) was orally administered for 13 wk starting at the age of 5 wk, and the results were compared with those of vehicle-treated WF rats. At the age of 18 wk, vehicle-treated WF rats were associated with mild hypertension, nephropathy with proteinuria histological glomerular injury, and renal arteriolosclerosis in addition to hyperglycemia, hyperinsulinemia, and hyperlipidemia. Treatment with pioglitazone significantly improved glucose and lipid metabolism. In addition, it lowered blood pressure, decreased proteinuria, and prevented glomerular injury, renal arteriolosclerosis, and aortic medial wall thickening, whereas body weight, food intake, sodium balance, and urinary norepinephrine excretion were significantly increased. These results suggest that the insulin-sensitizing agent pioglitazone is effective in correcting not only glucose and lipid metabolism but also cardiovascular and renal complications in non-insulin-dependent diabetes mellitus.

A Preliminary Study of the Effects of Venlafaxine on 24‐Hour Urinary Catecholamine Excretion Profile

Objective: To investigate the effects of venlafaxine on the 24‐hour urinary catecholamine excretion profile in patients treated with this drug for depression.Method: Patients to be treated with venlafaxine for the management of a depressive illness were requested to provide a 24‐hour urine sample immediately before the commencement of therapy. The urinary concentrations of adrenaline and noradrenaline were determined, and the 24‐hour urinary catecholamine excretion profile was calculated. This procedure was repeated after treatment with venlafaxine for 14 days.Results: Eight patients were enrolled in the study, but three patients did not complete the protocol because of adverse drug reactions. The effects of venlafaxine treatment on the profile of urinary catecholamine excretion were assessable in five patients. The mean 24‐hour excretion of noradrenaline appeared to be decreased after venlafaxine treatment, but this decrease failed to attain statistical significance. The 24‐hour urinary excretion of adrenaline was unchanged after venlafaxine, but the ratio of noradrenaline:adrenaline urinary excretion decreased significantly after treatment.Conclusions: This small prospective study demonstrates an altered profile of urinary catecholamine excretion in patients treated with venlafaxine for depression for two weeks. Further research is needed to determine whether there is a correlation between the effects of venlafaxine on urinary noradrenaline excretion and the therapeutic and/or adverse effects of this antidepressant.Aust J Hosp Pharm 1997; 27: 232–3.

Does orthostatic testing have any role in the evaluation of the young subject with mild hypertension?: an insight from the HARVEST study.

The aim of the study was to assess the clinical significance of the blood pressure (BP) reaction to standing in 1029 stage I hypertensives. Office BP was measured six times in the supine position and six times after 2 min of standing. All subjects underwent 24-h ambulatory BP monitoring, and measurements of 24-h urinary epinephrine and norepinephrine excretion. Echocardiography was performed in 636 patients. With use of mixture analysis we could single out a population with abnormal diastolic BP response to standing (hyperreactors, n = 95). These subjects had a diastolic BP increase from lying to standing of >11 mm Hg. The other subjects were defined as normoreactors (n = 934). Office systolic BP was similar in the two groups. Diastolic BP was lower (91 +/- 6 mm Hg v 95 +/- 5 mm Hg, P < .0001) and heart rate was higher in the hyperreactors (77 +/- 10 beats/min v 75 +/- 9 beats/min, P = .004). After adjusting for age, gender, and smoking habits the statistical significance did not change. Adjusted 24-h systolic BP (P = .02) and diastolic BP (P = .02) were higher in the hyperreactors than in the normoreactors. Hyperreactors were characterized by higher cardiac index (3.2 +/- 0.8 L/min/m2 v 3.0 +/- 0.7 L/min/m2, P = .008 for adjusted values), lower total peripheral resistance (1420 +/- 330 dyne/sec/cm(-5) v 1600 +/- 380 dyne/sec/cm(-5), P = .003), and higher urinary norepinephrine output (114.9 +/- 80.3 microg/24 h v 90.6 +/- 78.5 microg/24 h, P = .03). Dimensional echocardiographic data and albumin excretion rate did not differ between the two groups. In conclusion, mixture analysis allowed us to identify a population of young mild hypertensives with exaggerated BP response to standing. Hyperreactors were characterized by higher whole-day BP and by a hyperkinetic hemodynamic pattern as a result of increased sympathetic tone.

ST-segment changes and catecholamine-related myocardial enzyme release during alcohol withdrawal.

ST-segment changes and biochemical signs of myocardial injury, and their relation to sympatho-adrenergic activation and cardiac function, were studied in a case series of 19 alcohol-dependent (DSM-III-R) men undergoing in-hospital treatment for alcohol withdrawal. No patient had any clinically apparent heart disease. Analyses of ST-segment depressions > or = 0.1 mV from 24 h ambulatory electrocardiographic recordings revealed horizontal or downsloping ST-segment depressions in seven of the patients. The serum concentration of creatine kinase (CKMB) the day after admission correlated with the urinary excretion of adrenaline (r = 0.74, P < 0.001) and noradrenaline (r = 0.71, P < 0.001). In the two patients with the highest adrenaline excretion and the highest serum concentrations of CKMB and cardiac troponin T, horizontal ST-segment depressions were detected as well. The left ventricular ejection fraction was > or = 0.65 (range 0.65-0.79) in all of the 17 alcoholic men who were examined by echocardiography. Our study shows that alcohol withdrawal is frequently associated with ST-segment abnormalities in men without impairment of heart function and that sympatho-adrenergic activation during withdrawal seems to influence the release of myocardial enzymes. Alcohol withdrawal should thus be considered a condition in which acute cardiac complications may be expected in susceptible individuals.

The Effects of a 4-Day March on the Lower Extremities and Hormonal Balance

The functional strength, flexibility, and ranges of motion of the lower extremities, as well as hormonal balance, estimated by urinary excretion of adrenaline and noradrenaline and serum determinations of testosterone and cortisol, were studied with six physically active army officers participating in a 4-day march totaling 185 km. Catecholamine excretion rates showed cumulatively increased sympathoadrenal stress, and the effects on serum testosterone and cortisol concentrations were minor. Also, leg measurements showed no signs of edema, decreases in flexibility, or decreases in functional strength. Most pain (75%) experienced by the subjects was located in the feet and caused by abrasions and blisters. Only a small portion of perceived pains (25%) was associated with muscle soreness. Serum creatine kinase activity was slightly (ca. 400-650%) increased during the marching days. Thus, soldiers who are in good physical condition and are accustomed to marching are able to walk four marathons on successive days, while carrying 10-kg backpacks, without any major adverse effects on the musculature of their lower extremities.

Urinary excretion of adrenaline and noradrenaline during hypoglycaemic clamp in diabetic and non-diabetic adolescents

The urinary excretion of non-conjugated adrenaline and noradrenaline during hypoglycaemic clamp was investigated in 16 diabetic and 15 non-diabetic adolescents. In the diabetic adolescents, the mean excretion of adrenaline was approximately nine times higher in clamp urine than in morning urine (p < 0.0001). In the non-diabetic adolescents, the mean excretion of adrenaline was 20-30 times higher in clamp urine than in morning urine (p < 0.0001). Plasma catecholamines were measured, and the area under the plasma concentration- time curve (AUC) and renal clearance of catecholamines were calculated. There was a linear correlation between the AUC and the urinary excretion of adrenaline (r=0.57, p= 0.001) and noradrenaline (r=0.49. p= 0.006) during the hypoglycaemic clamp. The renal clearance of adrenaline and noradrenaline did not differ between the diabetic and non-diabetic subjects. In the diabetic group, there was a positive correlation between HbA, and the adrenaline excretion in clamp urine (r =0.60, p = 0.015). The eight diabetic subjects with HbAjc < 10% had lower adrenaline excretion in clamp urine than the subjects with HbAjc > 10% and the non-diabetic subjects (all p values < 0.05). We conclude that there is a marked increase in urinary adrenaline excretion during hypoglycaemia in diabetic and non-diabetic adolescents. The increase in adrenaline excretion during hypoglycaemia was attenuated in the better-controlled diabetic adolescents in our study.

An increase in noradrenaline excretion during prolonged mental task load.

To investigate the effects of prolonged mental work, urinary excretion of catecholamines and cortisol was measured in 18 human subjects from 9:30 to 17:00. On the "task day,' the subjects performed mental tasks during the morning (10:20-11:45) and afternoon sessions (13:00-17:00), otherwise taking chair rest. On the "control day,' the subjects took chair rest in the afternoon after performing mental tasks in the morning. In the morning session, urinary excretion of adrenaline during mental work increased greatly compared to that before the mental work. Mental work in the afternoon session also caused a marked increase in adrenaline excretion compared to the rest level in the afternoon on the control day. Cortisol levels in the first hour of the afternoon mental work were significantly higher than those during the corresponding time on the control day. Urinary excretion of noradrenaline during mental work in the morning session only increased slightly compared to that before the mental work. In the afternoon session, however, noradrenaline excretion during mental work on the task day was markedly elevated compared to that during the rest condition at the corresponding time on the control day. These findings suggest that prolonged exposure to mental work, but not short-term mental work, produces a marked increase in noradrenaline excretion in human subjects.

Expression of constitutive Nitric Oxide Synthase messenger RNA in the Rat Brain

Endogenous nitric oxide (NO), identified as one of the endothelium-derived relaxing factors, exists not only in the vascular endothelium, but also in other organs and tissues including the brain. Although the physiological roles of NO are not clearly defined yet, NO may be involved in the pressor mechanisms of salt loaded hypertension. To study the role of brain NO in the cardiovascular regulation of salt loaded hypertension, we measured semiquantitatively the constitutive NO synthase (cNOS) messenger RNA in salt-restricted or salt-loaded rats, and DOCA-salt hypertensive rats by using a reverse transcription-polymerase chain reaction. Relative expression levels of cNOS messenger RNA in the hypothalamus of the DOCA-salt hypertensive rats were significantly reduced as compared to those in the control rats, whereas urinary excretions of arginine vasopressin and norepinephrine were significantly increased in DOCA-salt hypertension. cNOS messenger RNA in the hypothalamus of salt-restricted rats showed a tendency to increase as compared to those in the high salt loaded rats. These results suggest that NO synthesized by cNOS in the hypothalamus may attenuate both the vasopressin releases and sympathetic nervous activities, which result in the inhibition of the pressor mechanisms of salt loaded hypertension.

Insulin resistance, hyperglycemia, glucosuria, and galactosuria in intensively milk-fed calves: dependency on age and effects of high lactose intake.

Calves intensively fed milk replacers frequently develop postprandial insulin resistance, characterized by excessively elevated plasma insulin concentrations, hyperglycemia, and glucosuria. To test the hypothesis that insulin secretion and insulin-dependent dependent glucose metabolism are modified by age and carbohydrate intake, 20 male calves (Simmental x Red Holstein) were fed a milk replacer containing 290 and 423 g lactose/kg DM from 60-70 to 190-200 kg BW. Responses of insulin and glucose to milk replacer intake and orally administered glucose and pre- and postprandial glucose responses to i.v. infused glucose and i.v. injected insulin were tested at 75-105 and 160-200 kg BW. Urine was collected during 24h to determine glucose, galactose, dopamine, noradrenaline, and creatinine excretion. Insulin resistance, hyperinsulinemia, hyperglycemia, glucosuria, and galactosuria developed with increasing age and occurred primarily postprandially. High lactose intake enhanced postprandial hyperglycemia but did not significantly increase glucosuria, galactosuria, and hyperinsulinemia. Based on urinary excretion of dopamine and noradrenaline there was a marked age-dependent increase in the activity of the sympathetic nervous system, which was not modified by lactose intake. high feeding intensity and lactose intake, excessive hyperinsulinemia per se and enhanced activity of the sympathetic nervous system possibly contributed to the development of insulin resistance. Glucose-dependent insulinotropic polypeptide, growth hormone and cortisol concentrations, and iron intake were low and comparable in both groups and therefore were etiologically not involved in the development of insulin resistance. Increasing circulating concentrations of insulin-like growth factor I during growth may have in part allowed high growth rates in the presence of insulin resistance.

Effect of CL316,243, a highly specific β 3-adrenoceptor agonist, on sympathetic nervous system activity in mice

To examine whether long-term administration of a β 3-adrenoceptor agonist influences sympathetic nervous system (SNS) activity, norepinephrine (NE) turnover, a reliable indicator of SNS activity, in the interscapular brown adipose tissue (IBAT), the heart, and the spleen, as well as urinary excretion of NE, were measured using mice treated with CL316,243 (CL), a highly specific β 3-adrenoceptor agonist, at a dose that stimulated thermogenesis and reduced body weight. CL significantly decreased NE turnover in the IBAT, heart, and spleen and decreased urinary excretion of NE without affecting food intake over 1 to 4 weeks of treatment. These findings show that long-term administration of the β 3-adrenoceptor agonist decreases SNS activity and urinary excretion of NE.

Effects of insufficient sleep on blood pressure monitored by a new multibiomedical recorder.

Blood pressure varies in relation to factors such as physical activity, body position, ambient temperature, and autonomic nervous system activity. Therefore, we have developed a portable multibiomedical (PMB) recorder that monitors five parameters: indirect blood pressure, physical activity, body position, ambient temperature, and RR interval of the electrocardiogram. In the present study, we applied the PMB recorder over a 24-hour period to study the effect of insufficient sleep on blood pressure in subjects doing extensive overtime work. The parameters listed above were measured by the PMB recorder throughout a normal workday (mean period of sleep, 8 hours) and throughout a day with insufficient sleep (mean period of sleep, 3.6 hours) in 18 male technical workers aged 23 to 48 years old. Blood pressure (mean systolic/diastolic pressure +/- SD) significantly increased the day after a sleep-insufficient night (129 +/- 8/79 +/- 6 mm Hg) compared with the day after a normal night (123 +/- 8/76 +/- 7 mm Hg, P<.05). However, ambient temperature, mean number of steps per minute, and percentage of time spent in a standing position showed no significant difference between these days. Spectral analysis of RR intervals showed that the ratio of the low-frequency component on the RR power spectrum (0.05 to 0.15 Hz) to the high-frequency component (0.15 to 0.40 Hz) was higher on the sleep-insufficient day (2.17 +/- 0.37 versus 1.81 +/- 0.37), as was the urinary excretion of norepinephrine (P<.05). Heart rate was significantly higher on the sleep-insufficient day (81 +/- ll versus 76 +/- 8 beats per minute), after the data of two subjects with abnormal levels of physical activity were excluded (P<.Ol). These data suggest that lack of sleep may increase sympathetic nervous system activity on the following day, leading to increased blood pressure. The PMB recorder was useful for precisely evaluating the relationship between blood pressure and environmental factors.

Comparison of renal function under deliberate hypotension during epidural plus light-enflurane anesthesia and during enflurane anesthesia.

We compared the effects of deliberate hypotension induced with trimethaphan on renal function and renal tubular damage under combined epidural and light-enflurane anesthesia (epidural group) and enflurane anesthesia alone (enflurane group). The mean arterial blood pressure was maintained at 50-55 mm Hg for 2.5 h in both groups using continuous infusion of trimethaphan. The urine volume and free water clearance were significantly greater in the epidural group than in the enflurane group [1.8±1.8 (SD)vs 0.4±0.3 ml·kg-1·h-1 and 0.81±1.30vs -0.15±0.22 ml·min-1, respectively] (P<0.05). The creatinine clearance and fractional sodium excretion rate did not differ significantly between the two groups. Urinary excretion of norepinephrine was significantly less in the epidural group than in the enflurane group (P<0.05); however, epinephrine excretion did not differ. Urinary excretion ofN-acetyl-β-D-glucosaminidase was significantly less in the epidural group than in the enflurane, group (4.2±2.5vs 12.2±4.6 U·g-1 CR) (P<0.01). The plasma antidiuretic hormone concentration was significantly lower in the epidural group compared to the enflurene group (13±23vs 57±42 pg·ml-1) (P<0.05). No significant difference in plasma atrial natriuretic peptide concentration was found between the groups. We conclude that renal function during trimethaphan-induced hypotension is better maintained under epidural plus light-enflurane anesthesia than under enflurane anesthesia alone.

Circadian blood pressure in patients in a persistent vegetative state.

We examined circadian variations in blood pressure, pulse rate, and other physiological variables, including hormone levels, in 16 patients in a persistent vegetative state (mean age -/+ SE; 66.1 -+/ 3.9 yr). Cerebrovascular accident was responsible for brain damage in 12 (75%) of the 16 patients. Blood pressure was measured for 24 h with an ambulatory blood pressure monitoring device. We monitored the temperature of the urinary bladder and measured urinary excretion of epinephrine, norepinephrine, 17-hydroxycorticosteroids, water, and sodium. When data were analyzed by analysis of variance, significant circadian changes were observed in body temperature and urinary excretion of hormones and sodium, but not in blood pressure or pulse rate. Individual analysis of rhythmicity using the cosinor method detected small but significant circadian variations in blood pressure and pulse rate in five of six patients who showed a simple organized response to noxious external stimuli. The disappearance of variation in blood pressure in patients in a vegetative state appeared to be related, in part, to the lack of response to external stimuli. Our findings suggest that the circadian variation in blood pressure may largely depend on external environmental factors.