Determination Of Plasma Catecholamines Research Articles

Phaeochromocytoma: a ten-year survey.

We retrospectively evaluated our experience with phaeochromocytoma from January 1986 to December 1995. There were 18 patients with surgically-proven phaeochromocytoma: three males, 15 females, aged 12-81 years (mean 42 years) at diagnosis. Sixteen were hypertensive; only 6/18 presented with two or more of the classical triad of headaches, palpitations and diaphoresis. One patient presented with hypertensive crisis. Duration of symptoms prior to diagnosis was 2 weeks to 6 years, mean 16.4 months. Sixteen patients had adrenal tumours and two had extra-adrenal tumours or paragangliomas. One had bilateral adrenal tumours and two had a combination of both adrenal and extra-adrenal tumours. There were four familial cases: two had multiple endocrine neoplasia type IIA (MEN-IIA), one had neurofibromatosis type I (NF-I) and one von Hippel-Lindau (VHL) disease. One patient had Cushing's syndrome arising from ectopic production of adrenocorticotropic hormone (ACTH) by the phaeochromocytoma. Disease was recurrent in three patients. Pre-operative diagnosis was confirmed mainly by elevated urine vanillylmandelic acid (VMA) and/or catecholamine levels. Twelve patients had plasma catecholamine determinations: noradrenaline was elevated in all, adrenaline in six and dopamine in two. Pre-operative localization was by CT scan or MR imaging in all patients. At follow-up of 1-10 years (median 4.8 years), 15 patients were cured surgically while two were asymptomatic despite recurrence of disease. One patient with recurrent paragangliomas died post-operatively.

Cortisol Response to Exercise and Post-Exercise Suppression of Blood Lymphocyte Subset Counts

This study examined a temporal relationship between exercise-induced changes in blood cortisol levels and circulating leukocyte and lymphocyte subset counts during and after exercise. Twenty-one young male, sedentary subjects [mean age, 20.8 +/- 2.4 (SD) yr; mean VO2max, 48.0 +/- 7.9 (SD) ml/kg/min] underwent a cycle ergometer exercise for 60 min at 60% VO2max. Peripheral blood samples, collected every 30 min during exercise and at 30, 60 min, 2.5 and 6 h of recovery, were used for the determination of serum cortisol and plasma catecholamines; lymphocyte subsets were analyzed by flow-cytometry. Based on the analysis of serum cortisol levels in response to exercise, the subjects can be identified as two groups: cortisol-responder (n = 13) and non-responder (n = 8) groups. Other than the cortisol response, the two groups showed no significant differences in terms of age, physical build, aerobic fitness, maximal heart rate, and pre-exercise blood leukocyte and lymphocyte subset counts. The two groups also did not differ significantly in their relative work rate and catecholamine response to the exercise. Both cortisol responder and non-responder groups displayed a granulocytosis, lymphocytosis and monocytosis during exercise, and a further granulocytosis after exercise. Changes in lymphocyte count and distribution during recovery, however, differed significantly between the two groups. In the circulation of the cortisol non-responder group, total lymphocyte counts returned to the baseline level shortly after exercise, whereas a significant lymphopenia occurred at 2.5 h of recovery in the cortisol responder group: the CD4+ cells showed the greatest decrease in cell count, followed by the CD8+ cells. In both groups, the CD16+ cell-counts tended to decline below the pre-exercise values at 30 and 60 min of recovery and returned to the baseline values by 2.5 h of recovery. The CD19+ cell-count was not suppressed in both groups after exercise. These results suggest that exercise-induced secretion of blood cortisol may contribute to post-exercise suppression of the helper- and cytotoxic-T cell counts, but does not seem to be involved in post-exercise changes in the NK-cell and B-cell counts as well as in post-exercise granulocytosis.

Thin‐layer Chromatographic Determination of Catecholamines in Rat Plasma

Thin‐layer Chromatographic Determination of Catecholamines in Rat Plasma

Thin-layer chromatographic determination of catecholamines in rat plasma.

A TLC method for the quantitative determination of epinephrine, norepinephrine and dopamine in rat plasma is described. After deprotenization, catecholamines were adsorbed on acid-alumina and acetylated. The acetyl derivatives were extracted using a C18 minicolumn, resolved on HPTLC plates and quantitated by fluorescence densitometry at 415 nm, using isoprenaline as internal standard.

Determination of Catecholamines in Human Plasma by HPLC with Electrochemical Detection

An assay procedure is described to quantitate low picogram concentrations of catecholamines in human plasma using reversed phase ion-pair HPLC with electrochemical detection. Optimization of chromatographic conditions allows use of samples as small as 0.25 mL. The overall recovery of 78% offers high precision and accuracy at low concentrations. The lower limit of detection is 0.87 pg/mL for epinephrine, 3.5 pg/mL for norepinephrine and 8.3 pg/mL for dopamine.

Haemodynamic and plasma catecholamine responses during total intravenous anaesthesia for laryngomicroscopy

We compared the haemodynamic responses to endolaryngeal procedures during anaesthesia with propofol or thiopentone. Two minutes after administration of glycopyrronium 4 micrograms.kg-1 and alfentanil 17.5 micrograms.kg-1 anaesthesia was induced with either propofol 2.0 mg.kg-1 (n = 8) or thiopentone 5.0 mg.kg-1.min-1, respectively. Muscle relaxation was induced and maintained with suxamethonium. Intratracheal jet-ventilation (rate: 20 breath.min-1) was with 100% oxygen. Blood samples for later determination of plasma catecholamines were drawn and haemodynamic responses were recorded at tracheal intubation, after insertion of the operating laryngoscope, during the endolaryngeal procedure and after extubation. With both anaesthetic agents the only statistically significant haemodynamic response to intubation was a rise of heart rate. With propofol, plasma adrenaline concentrations decreased significantly after induction and remained below baseline values throughout the procedure. After insertion of the operating laryngoscope the haemodynamic response was more pronounced with thiopentone than with propofol. Propofol blocks the catecholamine and haemodynamic responses to endolaryngeal procedures more effectively than thiopentone.

Socially defeated male rats display a blunted adrenocortical response to a low dose of 8-OH-DPAT

The study examined in male Wistar rats the influence of social defeat on the neuroendocrine stress response system using injection of the 5-HT 1A receptor agonist, 8-hydroxy-2-(di- n-propylamino)tetralin (8-OH-DPAT), as the pharmacological challenge. Social defeat was defined by the submissive postures displayed by the Wistar rats which were threatened and attacked by Tryon Maze Dull S3 rats for 10 min. 18–20 h after social defeat, the defeated rats were injected intravenously (i.v.) with a low and high dose of 8-OH-DPAT in their home cages. Blood samples were withdrawn from the freely moving cannulated rats for determination of plasma corticosterone and catecholamines. The corticosterone response to the low dose of 8-OH-DPAT (0.05 mg/kg, i.v.) was significantly diminished in the defeated rats as compared to the controls, but this dose failed to affect catecholamine concentrations. The high dose of 8-OH-DPAT (0.15 mg/kg, i.v.) significantly elevated corticosterone and adrenaline levels in defeated and control rats to the same extent, whereas no effect on noradrenaline was found. The present data thus indicate that social defeat blunts 5-HT 1A receptor-mediated adrenocortical activation probably via a decrease in the sensitivity of a population of postsynaptic 5-HT receptors.

Chemiluminescence determination of catecholamines in human blood plasma and urine using 1,2-diphenylethylenediamine as pre-column derivatization reagent in liquid chromatography

A chemiluminescence detection of the fluorescent derivatives of catecholamines (norepinephrine, epinephrine and dopamine) and isoproterenol as an internal standard is described for the highly sensitive liquid Chromatographic determination of these compounds. The amines were converted by reaction with 1,2-diphenylethylenediamine into the corresponding fluorescent derivatives, which were separated on a reversed-phase column (TSK gel ODS-120T) with isocratic elution. The derivatives in the column eluate were detected by the post-column chemiluminescence reaction system using bis[4-nitro-2-(3,6,9-trioxade-cyloxycarbonyl)phenyl] oxalate and hydrogen peroxide. The method allowed the determination of catecholamines in 50 μl of human blood plasma and 10 μl of 20 times diluted urine. The detection limits for the amines were 150–450 amol per 100-μl injection volume at a signal-to-noise ratio of 3.

Determination of catecholamines in urine and plasma by on-line sample pretreatment using an internal surface boronic acid gel

An automated method of analysis of catecholamines using a new packing material, internal surface boronic acid gel, was developed. The new support is designed with a carboxymethylcellulose-bonded external surface in order to be non-adsorptive to proteins and with a phenylboronic acid-bonded internal surface to retain only catecholamines. This packing support displayed an affinity for basic or neutral catecholic compounds with no protein adsorption and enabled on-line sample pretreatment of catecholamines in urine and deproteinized plasma. The catecholamines were selectively adsorbed on the new material and separated on a reversed-phase or a cation-exchange column. These compounds were then detected electrochemically. The limits of quantitation were 1.5–3.0 ng/ml in urine and 10–15 pg/ml in plasma, at a signal-to-noise ratio of 5.

Sympathetic nervous system and behavioral responses to stress following exercise training

This study tests the hypothesis that a short-term (16 weeks) exercise program modifies sympathetic nervous system (SNS) and selected behavioral responses to acute psychological stress. Twenty-four previously sedentary middle-aged men with maximal aerobic capacity ( V ̇ max O 2 ) values < 40 ml·kg −1·min −1 were assigned to experimental ( n = 12) and control ( n = 12) groups. All subjects performed a modified Stroop test (18 min) at pre- and postexercise training during which intravenous blood samples were drawn at three time intervals for plasma catecholamine (CA) determination. Motor performance was continuously recorded for assessment of premotor (PMT) and motor (MOT) components of reaction time. A set of anagrams were administered immediately following the modified Stroop to determine the level of cognitive fatigue induced. At both pre- and postexercise intervention, the total group ( n = 24) manifested significant ( p ≤ 0.05) elevations in state anxiety, heart rate, and plasma norepinephrine. No significant changes occurred over time on PMT or MOT. There were significantly ( p ≤ 0.01) lengthened anagram performance scores poststress compared to nonstress values. The experimental group exercise trained 3 days/week for 16 weeks, resulting in a 20% increase in V̇O 2max. However, there were no group differences on the CA or behavioral responses to the modified Stroop at pre- or postintervention. These findings do not support the hypothesis that short-term aerobic training significantly alters SNS activity or behavioral measures of central processing in middle-aged men exposed to an acute psychological challenge.

Elevated Plasma Levels of Neuropeptide Y Upon Electrical Stimulation of the Sympathetic Chain in Humans

Neuropeptide Y (NPY) a potent vasoconstrictor peptide, is co-stored with the classic neurotransmitter noradrenaline (NA) in certain peripheral sympathetic neurons and has been suggested to be a co-transmitter in vascular control. Surgical interruption of the sympathetic nerve supply of the upper extremity was performed to treat palmar hyperhidrosis in five patients. Intraoperative electrical stimulation (10 Hz; 0.5 ms; 0.5-3.0 mA) of the right and left sympathetic chains for 1 min was employed to determine the correct level for surgical excision. Blood pressure and heart rate were recorded continuously. Blood was sampled from the antecubital vein on the side subjected to stimulation for the determination of NPY-like immunoreactivity (LI) and plasma catecholamines. Blood samples were collected before and during stimulation, as well as 30 s and 2, 5, and 10 min after stimulation. A maximal blood pressure response was observed during the stimulation, but the magnitude varied markedly and was independent of the side on which the sympathetic chain was stimulated. During 3 of the 10 stimulations, the mean arterial blood pressure (MABP) increased 5-10 mm Hg, while in the other 7 an increase of 30-75 mm Hg was seen. No significant changes in heart rate or plasma adrenaline were found. The peak increase in NPY-LI plasma levels was noted 2 or 5 min after stimulation, while the corresponding peak for NA occurred during or 30 s after the stimulation. The maximal changes in plasma NPY-LI and NA were significantly correlated with the changes in blood pressure (NPY-LI, r = 0.80, p <0.01; NA, r = 0.84, p <0.01) as well as with each other (r = 0.95; p <0.001). It is concluded that, after electrical stimulation of the sympathetic chain in humans, plasma levels of both NPY-LI and NA rise, indicating release of these substances from sympathetic neurons. It is therefore possible that the vasoconstrictor peptide NPY is involved, together with NA, in the blood pressure response elicited by the stimulation.

Pheochromocytoma Associated with Prior Carotid Body Tumors (Chemodectomas)

Chemodectomas (carotid body tumors) were surgically removed on two occasions, first 10 years and then 3 months prior to detection with I-131 MIBG of an adrenal pheochromocytoma in a 32-year-old man with a family history of chemodectoma. Recent reports suggest patients with multiple and/or familial instances of chemodectoma frequently have associated catecholamine-secreting tumors detectable with I-131 or I-123 MIBG. This case documents the above association and suggests that any patient with proven carotid body tumor(s) be screened for catecholamine-secreting tumors via urinary/plasma catecholamine determinations.

Plasma catecholamine responses during a personalized physical stress as a dynamic characterization of essential hypertension

High performance liquid chromatography (HPLC) with electrochemical detection proves to be a reliable method for determination of plasma catecholamines (CA) to assess the possible role of the sympathetic nervous system (SNS) in essential hypertension (EH). The present investigation in a group of 15 normotensive (N) and 13 stable EH patients, homogeneous for age and duration of hypertension, was carried out without treatment in the supine position, up-right position and during a personalized bicycle exercise. Mean blood pressure, mean heart rate, plasma renin activity and plasma aldosterone were also evaluated at the various exertion phases. Norepinephrine (NE) and epinephrine (E) showed a progressive increase in N and in EH patients, reaching the highest values at maximum effort. However, EH patients showed higher E plasma levels than N before maximum effort. Dopamine (DA) reached the highest values in N at maximum effort and in EH patients at recovery time. These findings allow us to foresee the possibility of a better characterization of the SNS role in EH.

Automated Highly Sensitive Determination of Catecholamines in Plasma and Urine by High Performance Liquid Chromatography

Automated Highly Sensitive Determination of Catecholamines in Plasma and Urine by High Performance Liquid Chromatography

Cardiovascular and sympathoadrenal responses to mental stress: a study of sensory intake and rejection reactions

Cardiovascular, sympathoadrenal and subjective responses to mental stress induced by two mental challenges eliciting sensory intake (word identification test = WIT) and sensory rejection (colour word conflict test = CWT) reactions were studied in 10 healthy males. Pressor responses to these stressors have been proposed to differ haemodynamically. Sympathoadrenal activity was assessed by arterial and femoral venous plasma catecholamine determinations and direct recordings of muscle sympathetic activity in the right peroneal nerve (MSA). Basal measurements differed little from those made during an active relaxation procedure, with the exception of MSA, which decreased. Both stress tasks elicited increases in heart rate, cardiac output, calf blood flow and brachial and pulmonary arterial blood pressures. WIT and CWT elicited qualitatively similar responses, but the amplitudes of the circulatory responses were lower with WIT, which also was rated as a weaker stressor. MSA increased during CWT, while marginal increases were seen during WIT. Arterial adrenaline showed a transient increase by 0.14 nmol l-1 during WIT. During CWT arterial adrenaline increased significantly by 50%. Increases in arterial adrenaline and subjective stress ratings were related to increases in cardiac output and reductions of systemic vascular resistance. Arterial and femoral venous noradrenaline increased during CWT, while changes during WIT were small. MSA and noradrenaline responses did not correlate to local vascular responses in the calf. Differences in the responses to mental challenges evoking sensory intake or rejection seem to be of a quantitative rather than a qualitative character.

Determination of plasma catecholamines via condensation with diphenylethylenediamine: Simplification of the procedure

Determination of plasma catecholamines via condensation with diphenylethylenediamine: Simplification of the procedure

1,2-Diarylethylenediamines as pre-column fluorescence derivatization reagents in high-performance liquid chromatographic determination of catecholamines in urine and plasma.

Meso- and dl-1,2-diarylethylenediamines (14 species) were evaluated for pre-column fluorescence derivatization reagents in the high-performance liquid chromatographic determination of catecholamines (norepinephrine, epinephrine and dopamine) in human urine and plasma. Of the compounds, meso-1,2-bis(4-methoxyphenyl)ethylenediamine was most preferable for all the catecholamines in terms of sensitivity and selectivity. The detection limit for each catecholamine is approximately 0.5 fmol in a 50-microliters injection volume.

A general method for the quantitative determination of catecholamines in body fluids using off-line sample pretreatment and HPLC-ED analysis

Reversed phase HPLC with electrochemical detection (HPLC-ED) was used for quantitative determination of adrenaline, noradrenaline, and dopamine in several complex biological matrices, including plasma, uremic plasma, and urine. Three different methods of sample preparation for use in this clinical chemistry were tested. These were adsorption of catecholamines on alumina, organic solvent extraction after complex formation with diphenylborate, and adsorption of catecholamines on a cation exchange gel followed by organic solvent extraction of the elute. The selectivity and precision of the three methods were evaluated. The organic solvent extraction proved to be more precise and selective than adsorption on alumina (adrenaline: cv=3.80% vs. 7.58%; noradrenaline: cv=1.70% vs. 4.26%); it also proved suitable for use in the routine quantitative determination of catecholamines in plasma from patients with normal renal function (creatinine <1.2 mg/dl). However when working with uremic plasma or urine, a more selective sample preparation was required. In this case the adsorption of catecholamines on a cation exchange gel followed by organic solvent extraction of the elute was sufficiently selective and precise and thus allowed a reliable quantitative determination of adrenaline and noradrenaline from rather complex biological matrices (adrenaline: cv=6.2%; noradrenaline: cv=2.8%). Use of this specific method showed that basal plasma catecholamine levels in dialysis patients are comparable to those found in patients with normal renal function (adrenaline: 47.7±22.2 pg/ml; noradrenaline: 310.3±121.4 pg/ml).

Left Ventricular Response to Exercise and Autonomic Control Mechanisms in End-Stage Renal Disease

Left ventricular (LV) function during rest and during exercise was evaluated in patients with end-stage renal disease (ESRD) in whom other causes of LV dysfunction were eliminated through rigid selection criteria. Autonomic function was also assessed in these patients with Valsalva's maneuver and plasma catecholamine determinations. Echocardiography and radionuclide ventriculography in the group with ESRD revealed no abnormalities of LV wall motion or ejection fraction. During graded exercise, patients with ESRD achieved 85% of age-predicted heart rate, and no differences in exercise tolerance or LV function were observed. Valsalva's response was abnormal in patients with ESRD, and post exercise the norepinephrine level was markedly increased (12.5 +/- 1.43 vs 8.28 +/- 0.82 nmol/L). Our results fail to indicate an independent adverse effect of ESRD on LV function.

Determination of catecholamines in human plasma by high-performance liquid chromatography: comparison between a new method with fluorescence detection and an established method with electrochemical detection

We report a sensitive fluorimetric method, in which catecholamines are concentrated from plasma by liquid-liquid extraction and derivatized with the selective fluorescent agent 1,2-diphenylethylenediamine prior to chromatography. Optimal conditions for extraction, derivatization and chromatography were investigated. With α-methylnorepinephrine as internal standard, the chromatographic separations are complete within 6 min. Limits of detection are 0.3 pg for norepinephrine and epinephrine and 0.5 pg for dopamine. Coefficients of variation are low (3–7%). Comparison of plasma catecholamine values determined with this method and with an established method with electrochemical detection ( n=135) shows good correlation ( r=0.94–1.00), and regression lines are close to lines of identity.