Changes In Catecholamine Levels Research Articles

Self-administration of morphine by rats causes monoamine release in the anterior cingulate cortex

Monoamine content in the microdialysate from the anterior cingulate cortex was measured in rats after injections and self-administration of morphine. Forced intraperitoneal injection of morphine did not lead to appreciable changes in the monoamine levels in the dialysate. Self-administration significantly increased monoamine levels in the extracellular space of the anterior cingulate cortex. Changes in catecholamine levels in the extracellular space of the anterior cingulate cortex correlated with the intensity of self-administration. The more morphine the animals injected to themselves, the greater was the increment in dopamine and norepinephrine levels. It seems that the increase of serotonin content in the anterior cingulate cortex did not depend on blood morphine concentration, but just reflected the fact of narcotic self-administration. The release of serotonin from nerve endings in the anterior cingulate cortex gradually increased at the beginning of the session, after which serotonin concentration started to decrease. The results indicate that monoamines are released from nerve endings in the anterior cingulate cortex only in response to self-administration of morphine. Catecholamines were released after each self-administration of the narcotic, while serotonin release seemed to be associated with the general status of the animal realizing this behavior.

Short‐term fasting‐induced autonomic activation and changes in catecholamine levels are not mediated by changes in leptin levels in healthy humans

In animal models, the adipocyte-secreted hormone leptin increases energy expenditure by increasing sympathetic outflow but its role in humans remains to be elucidated. We evaluated whether inducing hypoleptinaemia (with and without administration of leptin at replacement doses) for 3 days would influence catecholamine levels and sympathetic and parasympathetic activity in healthy humans. We studied six normal-weight subjects in the General Clinical Research Center (GCRC) under three conditions: baseline fed state (control study) and two 72-h fasting studies (to decrease leptin levels), with administration of either placebo or replacement-dose recombinant methionyl human leptin (r-metHuLeptin) in a randomized, double-blind fashion. In each condition, 24-h urinary catecholamine levels, heart rate and heart rate variability (HRV), a standard tool for assessing cardiac autonomic modulation, were measured. Study parameters remained stable during the control condition and the baseline assessment of all three studies. In response to 72-h fasting, which decreased serum leptin levels by 80%, 24-h urinary norepinephrine and dopamine levels and heart rate increased while cardiac vagal modulation decreased (all P < 0.05). Replacement-dose r-metHuLeptin to keep leptin levels within the physiological range during fasting did not alter fasting-associated changes in heart rate, catecholamine levels or cardiac vagal tone. The findings of this controlled, interventional study indicate that changes in heart rate, catecholamine levels and cardiac vagal modulation associated with 72-h fasting are independent of regulation by leptin. Thus, changes in leptin levels within the physiological range do not seem to play a role in regulating autonomic function during short-term starvation in healthy humans.

The effects of age and streptozotocin diabetes on the sympathetic innervation in the rat penis

The objective was to describe the changes in catecholamine levels, noradrenaline (NA) release and the ultrastructural and immunohistochemical changes in the sympathetic nerves in the penis of STZ-diabetic rats. Amines were measured using HPLC. Nerves were studied using immunocytochemistry for tyrosine hydroxylase, and electron microscopy. Diabetic animals were compared with age-matched controls. The concentration of penile NA increases at least 2.5-fold after about 10 weeks of hyperglycaemia, is maintained for over 40 weeks. The rate of release of NA in the diabetics also increases approximately by fourfold. Immunohistochemical staining for tyrosine hydroxylase showed either no change or an increase in the levels of the enzyme around the central arteries and the outer coverings of the corpus cavernosum. Cavernosal nerves show increased intensity of staining for tyrosine hydroxylase, and the presence of dilated nerve fibres and engorged endings. The axons of the dorsal nerve of the diabetic penis have a smaller cross-sectional area that is most marked in unmyelinated axons. In the diabetic penis, the nerve endings appear to contain significantly more NA than the controls, and the turnover of noradrenaline is increased substantially. There is immunocytochemical evidence of an increase in staining for tyrosine hydroxylase, suggesting an increase in synthetic activity. These results are discussed in relation to the existing literature on the role of amines in normal and disordered erectile function. In particular, the increased concentration and turnover of NA in the diabetic rat contrasts with the fall in NA in cavernosal blood described during normal erection in humans.

Novel stressors affected catecholamine stores in socially isolated normotensive and spontaneously hypertensive rats

Catecholamines in some central (hypothalamus and hippocampus) and peripheral tissues (adrenal glands and heart auricles) of long-term socially isolated normotensive and spontaneously hypertensive rats exposed to novel immobilization stress were determined by a simultaneous single isotope radioenzymatic assay. Long-term isolation (21 days) produced depletion of hypothalamic norepinephrine (NE) stores and hippocampal dopamine (DA) stores in both normotensive and spontaneously hypertensive rats. Acute immobilization stress (2 h) significantly decreased NE and DA stores in hypothalamus and hippocampus of naive normotensive and spontaneously hypertensive rats controls. However, novel immobilization stress applied to normotensive rats previously subjected to long-term isolation produced no changes in catecholamine levels in hypothalamus, while resulting in somewhat higher depletion of NE stores in hypothalamus of spontaneously hypertensive rats treated in the same way. Novel immobilization stress decreased NE and DA stores in hippocampus of normotensive but was without effect on NE and DA stores of spontaneously hypertensive rats. Social isolation did not affect catecholamine stores in peripheral tissues but novel immobilization stress produced a significant decrease in catecholamine content. The results suggest that some central and peripherals tissues of spontaneously hypertensive rats and normotensive rats differ with regard to catecholamine content and that there are certain differences in their responsiveness to stress.

Differential Effects of Stress on Gene Transcription Factors in Catecholaminergic Systems

Long-term changes in catecholamine levels and expression of their biosynthetic enzymes are associated with several stress-related disorders such as elevated plasma norepinephrine in posttraumatic stress disorder and increased postmortem tyrosine hydroxylase in the locus coeruleus with major depression. Stress elevates tyrosine hydroxylase gene expression in the CNS and periphery. Increased transcriptional initiation was involved in this induction in the rat adrenal medulla and locus coeruleus in response to single as well as repeated immobilization stress (IMO). We examined the stress-triggered induction or phosphorylation of several transcription factors, which were previously shown to be able to modulate tyrosine hydroxylase transcription. A single episode of IMO triggered elevations of c-fos in both the adrenal medulla and locus coeruleus. With repeated daily IMO, Fra-2 was a major AP-1 factor induced in the adrenal medulla, but not in the locus coeruleus. Egr1 levels were markedly elevated in the adrenal medulla with both single and repeated IMO stress, but not in the locus coeruleus. In the locus coeruleus, increased phosphorylation of CREB was observed after both single and repeated IMO. Results implicate differential transcription pathways in mediating elevation of gene expression of tyrosine hydroxylase, and other target genes, in these locations.

Präoperative Katecholamin-Effekte auf Blutfette und Magnesiumwerte können ein Leberversagen nach Leberresektionen vorhersagen

BACKGROUND: Our previous investigations demonstrated that there is an enormous increase in free catecholamines during prolonged intraoperative occlusion of blood flow to the liver (Pringle maneuver), with tachycardias indicating impending postoperative liver failure. As stress-induced changes in catecholamine levels also have clear metabolic consequences, we investigated changes in catecholamines and their metabolites before, during, and after surgery, looking for simple risk parameters that could serve as early onset predictors of postoperative liver failure. METHODS: We examined 26 patients with primary and secondary liver tumors. Their average age was 54 years (range, 27–79). Twenty-one patients had segmental liver resections, 3 had hemihepatectomies, and 2 hydatid cysts were treated by pericystectomy. Blood samples were taken 2 days before and during all phases of surgery and the following parameters were determined: free plasma epinephrine, total serum calcium and magnesium, serum triglycerides, and serum cholesterol. Catecholamine plasma values were determined by high-performance liquid chromatography. The patients were subdivided into 2 groups: one including those with postoperative liver failure; and the other, those without liver failure. Statistical analysis was performed with Clinical Stress Assessment Software. RESULTS: In patients with liver failure (LF), perioperative catecholamine increase was about threefold higher when compared to the increase observed in non-liver failure patients (nLF). However, there were no preoperative differences in catecholamine levels among the groups. Unlike the results for the catecholamines, there were significant preoperative differences in cholesterol, triglycerides, and total magnesium values, which were all lower in the LF group. Perioperative fall in cholesterol correlated significantly with decreased calcium levels, an electrolyte well known to be discharged from the blood stream into tissues with increasing catecholamine effect. Such an increase could also be shown by perioperative positive correlations between glutamic oxalacetic transaminase and epinephrine. CONCLUSIONS: Estimation of the risk of postoperative liver failure is of great importance for the surgeon and the patient. Disproportionately large increases in catecholamines in the LF group point towards a relative increase in surgical stress in persons who already are metabolically maladapted. Such metabolic exhaustion is well documented by preoperative "pseudonormal", i.e., relatively low cholesterol and triglyceride levels, that are usually not to be expected in middle-aged patients. Along with low magnesium concentrations, such parameters can be used as preoperative predictors for postoperative liver failure.

Effect of cardiac resynchronization therapy on plasma catecholamines in patients with and without beta-blocker therapy

Purpose: Cardiac resynchronization therapy (CRT) has been shown to improve clinical status and left ventricular function in patients with congestive heart failure and intraventricular conduction delay regardless of beta-blocker therapy. We hypothesized that CRT would reduce sympathetic activation as reflected by plasma catecholamine levels. We also hypothesized that the use of beta-blockers would obscure these beneficial findings based upon beta-blocker modulation of sympathetic function. Methods: This study is a retrospective analysis of the Multicenter InSync Randomized Clinical Evaluation (MIRACLE) trial. Major inclusion criteria were heart failure (NYHA class III or IV), left ventricular ejection fraction ≤35%, left ventricular end diastolic dimension ≥55 mm, and QRS duration ≥130 ms. Blood samples were collected before implantation of the cardiac resynchronization device and six months after randomization to the control or CRT group. Plasma levels of norepinephrine (NE), epinephrine (EPI), and dopamine (DOPA) were measured by radioimmunoassay. Changes in catecholamine levels from baseline to 6 months were then compared between control and CRT group with the Mann-Whitney U-test. These analyses were also done in subgroups of patients with and without beta-blocker therapy. A p<0.05 was considered significant. Results: 225 and 228 patients were randomized to the control and CRT group, respectively. 159 and 168 paired catecholamines levels for control and CRT groups, respectively, were available for analysis. If beta-blockers were not considered, CRT did not change NE, EPI, and DOPA compared to placebo. Similarly, in patients on beta blockers, there were no significant changes. In contrast, in patients without beta-blockers, CRT reduced EPI (median change (control vs CRT): +2 vs 0 pg/mL; p=0.019) and CRT tended to decrease NE levels (median change (control vs CRT): +1 vs −61.5 pg/mL; p=0.057) compared to placebo. Conclusion: In this clinical trial, CRT resulted in a significant reduction in EPI levels and tended to decrease NE levels compared to placebo in patients without beta-blocker therapy. However, this effect was not seen in patients on beta-blockers. We conclude that CRT reduces sympathetic activation, but that this effect is obscured by the use of beta-blockers.

An experimental analysis of the catecholamines in hyperglycemia and acidosis induced rat brain.

Hyperglycemia and acidosis are the hallmark of diabetes. Since these factors play an important role in the diabetic complications, we have studied the brain catecholamine levels in hyperglycemic and acidotic conditions per se. Experimentally induced hyperglycemia and acidosis are accompanied by significant alterations in the catecholamine levels in discrete areas of the brain. We and others have shown that chronic or acute diabetes in animals as well as in human results in altered neurotransmitter levels. In the present study, hyperglycemia maintained by daily external administration of glucose for thirty days showed increased level of dopamine in striatum and hippocampus, elevation of norepinephrine in hippocampus, and increased level of epinephrine in hypothalamus, midbrain and pons medulla. The ammonium chloride induced acidosis demonstrated significant elevation of dopamine in midbrain and significant increase of norepinephrine in hypothalamus and midbrain, and increased level of epinephrine in hypothalamus, pons medulla and cerebral cortex. On the other hand, sodium acetoacetate induced acidosis did not show any significant change in the level of catecholamines in any of the areas studied. In conclusion, the changes in catecholamine levels observed in experimentally induced hyperglycemic as well as in acidotic conditions are closely related to the changes observed in spontaneous or alloxan or streptozotocin diabetic animals, thereby suggesting that these conditions may be responsible for the changes observed in diabetic animals.

Changes in catecholamine levels in short day-induced cotyledons of Pharbitis nil.

We investigated the effects of catecholamine on flower-induction in P. nil (cv. Violet). GC-SIM analysis identified dopamine for the first time in P. nil seedlings. Dopamine levels in the cotyledons did not show a significant change during the inducing dark treatment. The dopamine content of cotyledons exposed to various durations of darkness were 0.1-0.2 nmol/g fresh weight. The same content was found when cotyledons were exposed to continuous light.

Usefulness of the supine-rest maneuver before neurohormonal sampling

In congestive heart failure (CHF), several endocrine systems are progressively activated in an attempt to maintain a working hemodynamic. 1 Francis G.S Benedict C Johnstone D.E Kirlin P.C Nicklas J Liang C.S Kubo S.H Rudin-Toretsky E Yusuf S the SOLVD InvestigatorsComparison of neuroendocrine activation in patients with left ventricular dysfunction with and without congestive heart failure. Circulation. 1990; 82: 1724-1729 Crossref PubMed Scopus (1276) Google Scholar Measurements of various neurohormones, such as atrial natriuretic factor (ANF), the N-terminal part of its precursor (N-proANF), or the brain natriuretic peptide (BNP), as well as measurements of vasoactive paracrine peptides, such as endothelin-1 (ET-1), are increasingly advocated to evaluate the disease severity or to predict the adverse clinical outcomes. 2 McDonagh T.A Robb S.D Murdoch D.R Morton J.J Ford I Morrison C.E Tunstall-Pedoe H McMurray J.J.V Biochemical detection of left ventricular systolic dysfunction. Lancet. 1998; 351: 9-13 Abstract Full Text Full Text PDF PubMed Scopus (908) Google Scholar , 3 Selvais P.L Donckier J.E Robert A Laloux O Van Linden F Ahn S Ketelslegers J.M Rousseau M.F Cardiac natriuretic peptides for diagnosis and risk stratification in heart failure influences of left ventricular dysfunction and coronary artery disease on cardiac hormonal activation. Eur J Clin Invest. 1998; 28: 636-642 Crossref PubMed Scopus (84) Google Scholar By analogy with norepinephrine assays, it is common practice to use the so-called “30-minute supine rest” maneuver before sampling of these neurohormones. This procedure is supposed to blunt any stress-related changes in catecholamine levels. 4 Benedict C.R Shelton B Johnstone D.E Francis G Greenberg B Konstam M Probstfield J.L Yusuf S the SOLVD InvestigatorsPrognostic significance of plasma norepinephrine in patients with asymptomatic left ventricular dysfunction. Circulation. 1996; 94: 690-697 Crossref PubMed Scopus (288) Google Scholar This time-consuming procedure is certainly a major restriction when considering the implementation of neurohormone measurement as a standard tool in the evaluation or follow-up of large numbers of patients with CHF. Furthermore, it is also often believed that the plasma levels of natriuretic peptides will increase in the supine position and that the plasma levels of ET-1 will decrease. However, this is only an indirect inference from the observed decrease of natriuretic peptide plasma levels and of the increase in ET-1 plasma levels when assuming the upright position. 5 Nicholls D.P Riley M Elborn J.S Stanford C.F Shax C McKillop J.M Buchanan K.D Regulatory peptides in the plasma of patients with chronic cardiac failure at rest and during exercise. Eur Heart J. 1992; 13: 1399-1404 PubMed Google Scholar , 6 Solomon L.R Atherton J.C Bobinski H Green R Effect of posture on plasma immunoreactive atrial natriuretic peptide concentration in man. Clin Sci. 1986; 71: 299-305 Crossref PubMed Scopus (55) Google Scholar , 7 Westendorp R.G.J Roos A.N Riley L.C.M Walma S Frölich M Meinders A.E Chronic stimulation of atrial natriuretic peptide attenuates the secretory response to postural changes. Am J Med Sci. 1993; 306: 371-375 Crossref PubMed Scopus (5) Google Scholar , 8 La Villa G Vena S Conti A Fronzaroli C Brat A Lazzeri C Tosti Guerra C Madiai S Marra N Frachi F Plasma levels of brain natriuretic peptide in healthy subjects and patients with essential hypertension:response to posture. Clin Sci. 1993; 85: 411-416 PubMed Google Scholar , 9 Kaufman H Oribe E Oliver J.A Plasma endothelin during upright tilt relevance for orthostatic hypotension?. Lancet. 1991; 338: 1542-1545 Abstract PubMed Scopus (139) Google Scholar Surprisingly, there is no systematic and comparative study of the effects of this maneuver on the plasma levels of natriuretic or vasoactive peptides. The aim of the present study was to evaluate the real relevance of the supine-rest position in a healthy and cardiac population.

Measurement of intracavernosal catecholamine during a prostaglandin E1 test.

Background : Erectile dysfunction (ED) can be a cause of male infertility among young men. The prostaglandin E1 (PGE1) intracavernous injection test, an erectile function test, is known as an objective method of examining the penile vasculature system. However, some ED patients fail to sufficiently maintain an erection because of the stress load upon them during the test. Thus, we measured changes in catecholamine levels by stress loading when we performed dynamic infusion cavernosometry (DIC). Methods : Among the 221 ED patients undergoing a PGE1 test, 10 were selected as the subjects for the present study. These 10 patients were 25-56years of age, with a mean of 32.8years, whose maximal penile rigidity was normal, but in whom penile erection could not be maintained sufficiently in the PGE1 test. Stress loading via vibratory sensory measurement during the PGE1 test suppressed penile rigidity strongly. Catecholamine levels were measured by using blood samples obtained from the corpus cavernosum and the cubital vein when erection was suppressed by stress loading, pain caused by needle insertion, and also when erection recovered from the suppression. Dynamic infusion cavernosometry was performed after each blood sampling time, to check corporeal veno-occlusive function and cavernosal arterial flow. Results : Penile norepinephrine levels were 0.20±0.06ng/mL during a suppressed erection and 0.15±0.03ng/mL during an erection, showing a significantly higher level (Student's t-test, P=0.0309) during suppressed erection. The results of the DIC measurement indicated a normal corporeal veno-occlusive function and cavernosal artery in all cases. Conclusion : The results of the present study revealed that corporeal veno-occlusive function and cavernosal arterial flow are normal in men who have normal maximum penile rigidity, but cannot sufficiently maintain the erection in the PGE1 test, suggesting the involvement of stress-induced penile norepinephrine in the suppression of erection maintenance. (Reprod Med Biol 2002; 1: 11-15).

Long-term effects of St. John’s wort and hypericin on monoamine levels in rat hypothalamus and hippocampus

Hypericum perforatum L. (St. John’s wort) is one of the leading psychotherapeutic phytomedicines and, because of this, great effort has been devoted to clarifying its mechanism of action. Chronic effects of St. John’s wort and hypericin, one of its major active compounds, on regional brain amine metabolism have not been reported yet. We used a high-performance liquid chromatography system to examine the effects of short-term (2 weeks) and long-term (8 weeks) administration of imipramine, Hypericum extract or hypericin on regional levels of serotonin (5-HT), norepinephrine, dopamine and their metabolites in the rat brain. We focused our interest on the hypothalamus and hippocampus, as these brain regions are thought to be involved in antidepressant drug action. Imipramine (15 mg/kg, p.o.), Hypericum extract (500 mg/kg, p.o.), and hypericin (0.2 mg/kg, p.o.) given daily for 8 weeks significantly increased 5-HT levels in the hypothalamus ( P<0.05). The 5-HT turnover was significantly lowered in both brain regions after 8 weeks of daily treatment with the Hypericum extract (both P<0.05). Consistent changes in catecholamine levels were only detected in hypothalamic tissues after long-term treatment. Comparable to imipramine, Hypericum extract as well as hypericin significantly decreased 3,4-dihydroxyphenylacetic acid and homovanillic acid levels in the hypothalamus ( P<0.01). Our data clearly show that long-term, but not short-term administration of St. John’s wort and its active constituent hypericin modify levels of neurotransmitters in brain regions involved in the pathophysiology of depression.

Monoamine Oxidase in Neuropsychiatry and Behavior

Monoamine oxidase (MAO) catalyzes the oxidative deamination of a number of biogenic amines, including the key neurotransmitters serotonin (5-HT), norepinephrine (NE), and dopamine (DA) and the neuromodulator phenylethylamine (PEA). Two forms of MAO, designated “MAO A” and “MAO B,” have been identified on the basis of biochemical properties and, subsequently, by cloning the relevant genes. Of the two, MAO A exhibits a higher affinity for 5-HT and NE and for the inhibitor clorgyline (Johnston 1968), whereas MAO B has a higher affinity for PEA, benzylamine, and the inhibitor deprenyl (Knoll and Magyar 1972).

The study of maternal and fetal plasma catecholamines levels during pregnancy and delivery.

To study maternal and fetal plasma levels of catecholamines (CA) during pregnancy and delivery, especially changes in CA levels during fetal distress and conditions of different modes of delivery. Maternal and fetal plasma NE, E and DA levels were determined by high performance liquid chromatography (HPLC) for 16 non-pregnant women, 19 cases of early pregnancy, 17 cases of mid pregnancy, late pregnancy, spontaneous vaginal delivery and 53 cases of cesarean section. Plasma NE and DA levels decreased gradually with the advance of gestational weeks, and levels of plasma NE were significantly lower than those of non-pregnant women (P < 0.05). The levels of plasma CA in patients who had elective cesarean section were significantly lower than those who had vaginal delivery and emergency cesarean section (P < 0.01). However, CA levels of the cord artery in the vaginal delivery group were significantly higher than those in the cesarean section group (P < 0.01). Vaginal delivery is better than cesarean section for the newborn. If cesarean section is necessary, it is best for the newborn after onset of labor.

Catechol-O-methyltransferase-deficient mice exhibit sexually dimorphic changes in catecholamine levels and behavior.

Catechol-O-methyltransferase (COMT) is one of the major mammalian enzymes involved in the metabolic degradation of catecholamines and is considered a candidate for several psychiatric disorders and symptoms, including the psychopathology associated with the 22q11 microdeletion syndrome. By means of homologous recombination in embryonic stem cells, a strain of mice in which the gene encoding the COMT enzyme has been disrupted was produced. The basal concentrations of brain catecholamines were measured in the striatum, frontal cortex, and hypothalamus of adult male and female mutants. Locomotor activity, anxiety-like behaviors, sensorimotor gating, and aggressive behavior also were analyzed. Mutant mice demonstrated sexually dimorphic and region-specific changes of dopamine levels, notably in the frontal cortex. In addition, homozygous COMT-deficient female (but not male) mice displayed impairment in emotional reactivity in the dark/light exploratory model of anxiety. Furthermore, heterozygous COMT-deficient male mice exhibited increased aggressive behavior. Our results provide conclusive evidence for an important sex- and region-specific contribution of COMT in the maintenance of steady-state levels of catecholamines in the brain and suggest a role for COMT in some aspects of emotional and social behavior in mice.

Changes in catecholamine levels and turnover rates in hypothalamic, vocal control, and auditory nuclei in male zebra finches during development

The catecholamines norepinephrine (NE) and dopamine (DA) have been implicated in the sexual differentiation of brain and behavior and in species-specific learning in several species. To determine if these neurotransmitters might be involved in sexual differentiation of the vocal control system and song learning in male zebra finches, NE and DA levels and turnover rates were quantified in 10 behaviorally relevant brain nuclei [6 vocal control (VCN), 2 auditory (AN), and 2 hypothalamic (HN)] at four critical points during sexual differentiation of the VCN and the period of song learning, 25, 35, 55, and 90 days of age. Some birds were pretreated with α-methyl-para-tyrosine (αMPT) to allow estimation of NE and DA turnover rates. NE and DA levels in microdissected nuclei were quantified using high-performance liquid chromatography with electrochemical detection. αMPT treatment suppressed catecholamine synthesis just as effectively in juveniles as it does in adults and proved an effective method for estimating NE and DA turnover rates. Patterns of NE and DA function in most VCN and AN over development were quite different from those in HN in which NE and DA function changed gradually and showed no striking peaks. NE turnover rates changed significantly over development in all six VCN [nucleus interfacialis (Nlf), high vocal center (HVC), nucleus robustus of the archistriatum (RA), dorsomedial portion of the intercollicular nucleus (DM), Area X of the parolfactory lobe, and lateral portion of the magnocellular nucleus of the anterior neostriatum (IMAN)]; one AN [nucleus mesencephalicus lateralis pars dorsalis (MLd)], and one HN [preopticus anterior (POA)]. NE levels changed significantly in two VCN (Nlf and Area X). In Nlf, RA, Area X, IMAN, and MLd, NE levels and/or turnover rates showed a striking peak at day 25, which was not seen in HN. Both DA levels and turnover rates changed profoundly over development in 5 of 6 VCN (Nlf, RA, DM, Area X, and IMAN) and both AN (MLd and Field L). These nuclei showed striking peaks in DA levels and turnover rates, primarily on day 35 and/or 55, which then declined profoundly by day 90. This contrasted with the minimal change in DA turnover rates seen in one HN (POA) and the sixth VCN, HVC. In several VCN and AN, NE and DA levels and turnover rates during development reached levels never seen in adult males. Previous research has shown that catecholamine function is heightened in VCN during development compared to surrounding tissues. Our data demonstrate that NE and DA function during development shows pronounced peaks in most VCN not seen in HN. This is interesting because both VCN and HN are hormone sensitive, and both show hormone-modulated NE and DA function in adult males. The timing of these peaks suggests that increased catecholaminergic function may be involved in sexual differentiation of the VCN and song learning in finches. © 1998 John Wiley & Sons, Inc. J Neurobiol 34: 329–346, 1998

Changes in catecholamine levels and turnover rates in hypothalamic, vocal control, and auditory nuclei in male zebra finches during development

The catecholamines norepinephrine (NE) and dopamine (DA) have been implicated in the sexual differentiation of brain and behavior and in species-specific learning in several species. To determine if these neurotransmitters might be involved in sexual differentiation of the vocal control system and song learning in male zebra finches, NE and DA levels and turnover rates were quantified in 10 behaviorally relevant brain nuclei [6 vocal control (VCN), 2 auditory (AN), and 2 hypothalamic (HN)] at four critical points during sexual differentiation of the VCN and the period of song learning, 25, 35, 55, and 90 days of age. Some birds were pretreated with alpha-methyl-para-tyrosine (alphaMPT) to allow estimation of NE and DA turnover rates. NE and DA levels in microdissected nuclei were quantified using high-performance liquid chromatography with electrochemical detection. AlphaMPT treatment suppressed catecholamine synthesis just as effectively in juveniles as it does in adults and proved an effective method for estimating NE and DA turnover rates. Patterns of NE and DA function in most VCN and AN over development were quite different from those in HN in which NE and DA function changed gradually and showed no striking peaks. NE turnover rates changed significantly over development in all six VCN [nucleus interfacialis (Nlf), high vocal center (HVC), nucleus robustus of the archistriatum (RA), dorsomedial portion of the intercollicular nucleus (DM), Area X of the parolfactory lobe, and lateral portion of the magnocellular nucleus of the anterior neostriatum (IMAN)]; one AN [nucleus mesencephalicus lateralis pars dorsalis (MLd)], and one HN [preopticus anterior (POA)]. NE levels changed significantly in two VCN (Nlf and Area X). In Nlf, RA, Area X, IMAN, and MLd, NE levels and/or turnover rates showed a striking peak at day 25, which was not seen in HN. Both DA levels and turnover rates changed profoundly over development in 5 of 6 VCN (Nlf, RA, DM, Area X, and IMAN) and both AN (MLd and Field L). These nuclei showed striking peaks in DA levels and turnover rates, primarily on day 35 and/or 55, which then declined profoundly by day 90. This contrasted with the minimal change in DA turnover rates seen in one HN (POA) and the sixth VCN, HVC. In several VCN and AN, NE and DA levels and turnover rates during development reached levels never seen in adult males. Previous research has shown that catecholamine function is heightened in VCN during development compared to surrounding tissues. Our data demonstrate that NE and DA function during development shows pronounced peaks in most VCN not seen in HN. This is interesting because both VCN and HN are hormone sensitive, and both show hormone-modulated NE and DA function in adult males. The timing of these peaks suggests that increased catecholaminergic function may be involved in sexual differentiation of the VCN and song learning in finches.

Attenuation of the catecholamine responses by electroacupuncture on Jen–Chung point during postoperative recovery period in humans

In this study, Jen–Chung (J–C) point was stimulated by electroacupuncture (EA) in 10 patients, and by placebo treatment in 10 controls, immediately after termination of inhalation for 15 min. During the postoperative recovery period, plasma catecholamine (CA) levels were assessed before (0) and 15 and 30 min after treatment. The time from cessation of inhalation to the first eye opening and to extubation did not differ between groups. The plasma catecholamine levels increased by 30% from 0 to 15 min in the control group but decreased by 6% in the EA group. The levels at 30 min were approximately the same as at time 0. The change in catecholamine levels from 0 to 15 min was significantly lower ( P<0.02) in the EA groups than the control group.

Changes in catecholamine levels in the gut and frass of the corn earworm, Helicoverpa zea induced by dietary l-azetidine-2-carboxylic acid

Several studies have shown that a plant-derived lower homologue of proline, l-azetidine-2-carboxylic acid (AZC), fed to larvae of the corn earworm, Helicoverpa zea, induces toxicity leading to an array of developmental defects including incomplete pupal cuticular sclerotization or tanning. Destabilized cuticular tanning has recently been shown to be correlated with a deficiency in a hemolymph catecholamine, N-β-alanyldopamine (NBAD) (Okot-Kotber and Adeyeye, 1995). Analysis of gut and frass catecholamine contents has revealed that an AZC-supplemented diet induces a two-fold increase in the excretion of dopamine (DA) and β-alanine. Also, more 3,4-dihydroxyphenylalanine (DOPA) was excreted in this group than in the controls, although overall, less DOPA was detected than DA in both cases. Four catechols of unknown structure, designated FC1, FC2, FC3 and FC4 according to their relative chromatographic retention times, were found in frass extracts with relatively higher levels in the AZC-treated larvae than in the controls. Three of these, FC1, FC2 and FC3 were also found in the diet, but FC4 was detected only in frass. Gut tissue catecholamines were much higher (by approximately 100-fold) than found in the frass. Approximately two-fold higher DOPA and seven-fold higher DA concentrations were detected in the guts of pupae with incomplete tanning, that had developed from AZC-treated larvae, compared to the controls. It appears, therefore, that the deficiency in NBAD observed in the hemolymph of AZC-fed larvae is largely caused by a slower rate of acylation of DA into NBAD, which results in the accumulation of DA in the gut. The data suggests that there is a defective β-alanyldopamine synthetase in the AZC-treated insects rather than an increased catabolism of NBAD.

The effect of enteric bacterial toxins on the catecholamine levels of the rabbit

The rabbit catecholamine responses to bacterial toxins commonly found in Sudden Infant Death Syndrome (SIDS) victims were studied as part of a proposed animal model for SIDS. Six bacterial toxins commonly isolated from SIDS baby feces and a comparison endotoxin were injected intravenously (i.v.) and intraluminarily (i.l.) to determine their effects on catecholamine levels. I.v. injected toxins clearly altered catecholamine levels causing sharp rises in adrenaline and noradrenaline levels and at critical toxin concentrations sudden death ensued. Clostridium perfringens enterotoxin and alpha-toxin, Clostridium difficile enterotoxin (A) and cytotoxin (B), Escherichia coli STa toxin and staphylococcal enterotoxin B caused rises in catecholamine levels similar to that caused by E. coli endotoxin. Control rabbits showed very little or no obvious change in catecholamine levels. Clostridium difficile enterotoxin (A) and cytotoxin (B) injected i.v. exhibited synergy. Toxins injected into the duodenum, jejunum, ileum, cecum and large intestine caused behavioural changes ranging from reduced appetite and diarrhea to, in rare cases, death. Changes in the catecholamine levels of these animals however were not significantly different from those of the control animals. The results are discussed in relation to the possible effect of certain conditions (physiological, viral infections and environmental) which increase toxin permeability and allow absorption of these toxins, possibly resulting in sudden infant death.