Changes In Catecholamine Levels Research Articles

Study on Catecholamine Sensors Based on Noble Metal Nanoparticles Modified Ti3C2 Mxene

Catecholamines are neurotransmitters in the peripheral and central nervous systems, which maintain the normal physiological state of the human body. Studies have shown that the occurrence of many diseases are often accompanied by changes in catecholamine levels. Clinically, the detection of catecholamine levels in human plasma or urine can assist in the diagnosis of endocrine-related diseases and neurological diseases. However, catecholamines are easily oxidized, and the content in human body is very low. So the rapid detection of catecholamines is very important for the prevention and diagnosis of related diseases. In this paper, the electrochemical response characteristics of Ti3C2Tx MXene and noble metal nanoparticles modified Ti3C2Tx to dopamine (one type of catecholamine) were explored. The results shown that Ti3C2Tx would undergo irreversible oxidation at the anode potential and the single Ti3C2Tx modified electrode was not suitable for the detection of dopamine. So we further explored the modification of Pt and Au nanoparticles on the Ti3C2Tx/GCE electrode, and the experimental results shown that Au/Ti3C2Tx/GCE had higher sensitivity for measuring dopamine, while Pt/Ti3C2Tx/GCE had a larger linear range. Both electrodes had good stability and repeatability and could be used for the detection of catecholamines.

Perioperative Management of a Patient with a Nonsurgical Pheochromocytoma: Anesthetic Implications (Case Report)

Patients with nonsurgical malignant pheochromocytoma are at risk for major hemodynamic instability during periods of stress, including the perioperative period. Unpredictable changes in catecholamine levels are observed in these patients who are candidates for surgery other than adrenal tumor resection, which may lead to hemodynamic instability. For this reason, adequate preoperative preparation of patients with pheochromocytoma is considered as the mainstay of anesthetic management. This case report describes the perioperative management of a patient with a malignant pheochromocytoma who was to undergo a hemiarthroplasty following a left femoral neck fracture.

Streptozotocin-induced diabetes in rats modifies the role D2 , D3 and D4 dopamine receptors play in cardiac sympathetic inhibition.

Diabetes mellitus is associated with abnormalities in peripheral/central catecholaminergic systems, including changes in catecholamine levels and receptor expression. Since quinpirole-induced cardiac sympathetic inhibition is greater in diabetic than in normoglycemic rats, this study pharmacologically investigated the dopamine D2 -like receptor subtypes that mediate cardiac sympathetic inhibition in diabetic (streptozotocin [STZ]-pretreated) pithed rats. Fifty male Wistar rats were pretreated with STZ, pithed and conditioned for spinal stimulation (C7 -T1 ) of the tachycardic sympathetic tone. The resulting increases in heart rate were evaluated following i.v. blocking doses of antagonists at D2 , D3 and D4 receptors during a continuous i.v. infusion of quinpirole (an agonist at D2 -like receptors) or saline (vehicle). With this experimental approach, the cardiac sympathetic inhibition produced by quinpirole in diabetic rats was:(i) unchanged after administration of vehicles and; (ii) abolished by the antagonists L-741,626 (D2 ), SB-277011-A (D3 ) or L-745,870 (D4 ). These findings in diabetic pithed rats imply that: (i) the cardiac sympathetic inhibition by quinpirole involves activation of D2/3/4 dopamine receptors; and (ii) there is a differential stimulation of these receptors compared to normoglycemic rats. These D2/3/4 receptor subtypes could be a novel drug target for the therapy of typical cardiac complications of diabetes.

A simultaneous extraction/derivatization strategy coupled with liquid chromatography–tandem mass spectrometry for the determination of free catecholamines in biological fluids

The current study presents a convenient, rapid and effective simultaneous extraction/derivatization (SEDP) strategy for effective pretreatment of catecholamines (CAs). Commercial zirconium oxide (ZrO2) nanoparticles were employed for the selective capturing of cis-diol containing CAs to remove the biological interferences and phenyl isothiocyanate (PITC) was used for derivatization to improve the ionization and to improve the chromatographic separation. The extraction and derivatization procedures were integrated into one step to simplify the sample pretreatment. Excessive derivatization reagents were removed as well, reducing the degree of contaminations in mass spectrometry. The factors affecting the SEDP process were optimized and the results showed that the detection sensitivity and chromatographic separation of CAs greatly improved compared with underivatized CAs, during LC-MS/MS analysis. Combined with ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), quantifying the concentration of norepinephrine (NE), epinephrine (E) and dopamine (DA) in biological fluids was validated in ranges of 1-200.0 ng/mL with a satisfactory correlation coefficient (R2 > 0.997). The obtained recoveries were in the range of 91.0-109.5% with RSDs less than 9.4%. Finally, significant changes in CAs levels in urine samples of healthy people and pheochromocytoma patients were detected. The developed method offers comparative advantages in terms of sensitivity, specificity and selectivity.

UHPLC-HRMS determination of adrenaline and dopamine dansyl derivatives in human saliva

In the last decade, the quantification of catecholamines in human biological fluids has been of great interest. Changes in catecholamine levels, such as adrenaline and dopamine, in the body lead to neurological disorders as well as several diseases, namely Alzheimer’s and Parkinson’s diseases, neuroendocrine catecholamine - producing tumors - pheochromocytoma, paraganglioma, carcinoid tumors and neuroblastoma. Moreover, different drug combinations can lead to the distortions in the human biological passport, containing the information not only about the erythropoiesis and steroid profile, but also about catecholamine levels, which are difficult to quantify in terms of sample preparation and analysis. A method has been proposed for the determination of adrenaline and dopamine dansyl derivatives in human saliva, including the derivatization and determination of analytes by ultra-high-performance liquid chromatography (UHPLC) with high resolution mass spectrometric detection. The derivatization procedure allowed obtaining less polar catecholamine derivatives, which is especially important for their quantification by reversed-phase ultra-high-performance liquid chromatography since it ensures their better retention on the sorbent. The sensitivity of these substances quantification by the proposed method was estimated; the highest sensitivity was achieved using the mobile phase consisting of the 0.1% formic acid aqueous solution and acetonitrile. The lower limit of quantification was 5 ng/mL for dansyldrenaline and 10 ng/mL for dansyldopamine respectively. The proposed technique was tested on real saliva samples obtained from volunteers to quantify catecholamine dansyl derivatives by reversed-phase high-performance liquid chromatography with high-resolution mass spectrometric detection. High sensitivity of the technique allows using it for adrenaline and dopamine determination in clinical diagnosis.

Analysis of catecholamines levels in pregnant women with threatened preterm labour

Objective. Analysis of changes in catecholamines levels and their influence on gestation course with further prognostication and treatment of preterm labour.Material and methods. Changes of catecholamines levels in 200 pregnant women with preterm labour during 22-36 weeks of gestation were analyzed. The first (І) main clinical group involved 70 pregnant women with previous pregnancy loss without signs of threatened preterm labour during examination. The second (ІІ) main group included 80 pregnant with previous miscarriages with available signs of threatened preterm labour. The comparison group comprised 30 primigravidae at the same periods of gestation with threatened preterm labour without pregnancy loss or abortions in anamnesis. The control group involved 20 primigravidae with non-complicated gestation period. The age of pregnant ranged from 19 to 42 years (25,9 ± 6,7) and did not deviated considerably in the studied groups. The condition of sympathoadrenal system was estimated due to levels of adrenaline and noradrenaline excretion throughout 24 hours (Y. Sh. Matlina et al., 1969). The studied data were recorded in a questionnaire and were further accurately analyzed, taking into consideration obstetric and gynaecological history, gestation course before hospitalization, medical, biological, social and economic issues. Results. The condition of sympathoadrenal system was evaluated according to levels of adrenaline and noradrenaline excretion throughout 24 hours. The received data were recorded and carefully studied due to our modified questionnaire including obstetric and gynaecological history, gestation course before hospitalization, medical, biological, social and economic aspects. The obtained outcomes proved that reduced level of adrenaline excretion in comparison with the control adrenaline excretion level and increased level of noradrenaline excretion in pregnant with threatened preterm labour indicated insufficient adaptive response in prevalent majority of women with late miscarriage or premature delivery in anamnesis. It was determined that the activity of mediatory link of sympathoadrenal system exceeded the activity of its hormonal (adrenal) link. Since noradrenaline triggers noticeable contractile action of myometrium, defined changes may cause uterine contractile function and develop threatened miscarriage. Thus, identified considerable increase of indicators influenced adaptive responses in studied women that manifested disadaptation process. Conclusion. The performed study proved that changes in adrenaline and adrenaline levels indicated insufficient adaptive reaction in most pregnant with late miscarriages or preterm labour. Therefore, we suggest applying the elaborated algorithm of examination and risk prognostication for miscarriages in similar cases. It may ensure reducing perinatal losses and improving reproductive health of women.

Short-term exposure to repeated chasing stress does not induce habituation in Senegalese sole, Solea senegalensis

Animals can habituate to certain repeated stressors and reduce the physiological response that such stressor evoked initially. Studies related to stress habituation in fish are scarce and the available data differ depending on the species and on the type, duration and severity of the stressor. The main objective of this study was to investigate the stress response of juvenile Senegalese sole (Solea senegalensis) submitted to repeated chasing stress for 3days previous to the experiment in order to evaluate the occurrence of habituation to those stress conditions in this fish species. Thus, five different experimental groups were evaluated: not stressed fish (control, C), fish stressed only on the experimental day (ST/naïve), and fish stressed on the experimental day and on the 3 previous days: during the day (ST/Dt), at night (ST/Nt) or both (ST/Dt+Nt). Parameters related to primary and secondary responses to chasing were evaluated in plasma, liver and brain. Chasing in ST/naïve group induced incremented values of plasma cortisol, glucose and lactate but no changes in catecholamine levels compared to controls. In trained fish, higher cortisol but decreased glucose, lactate and catecholamine levels were observed after stress compared to controls and to ST/naïve groups. In the liver, stress did not induce any changes with respect to controls whereas ST/Dt and ST/Dt+Nt showed lower values of glucose and glycogen than stressed naïve fish. In the brain, ST/naïve group presented no significant changes in serotonergic activity. However, incremented serotonergic activity was detected in fish previously trained. Furthermore, dopaminergic activity decreased in diurnal trained and nocturnal trained groups with respect to ST/naïve fish. Crh expression in hypothalamus was higher in ST/naïve fish but not in fish submitted to repeated stress compared to controls. In summary, it seems that there was no habituation to the repeated acute stress protocol in Solea senegalensis in terms of serotonergic activity and cortisol release during the physiological stress response. However, the decreased levels of plasma catecholamines and energy metabolites, and of the hypothalamic crh mRNA abundance and dopaminergic activity, indicate a modulation of the stress response in trained fish. Altogether, the results suggest that either the chasing stressor was too strong or the training period too short for the animals to habituate, indicating that repeated chasing within short periods should be avoided when manipulating fish in order to keep proper welfare conditions in this species.

409: Impact of maternal anxiety on serum catecholamine levels and their role in fetal baseline heart rates during scheduled induction of labor, a prospective study

To determine whether there is a relationship between maternal anxiety, maternal serum catecholamine levels, and changes in the fetal baseline heart rates in women undergoing induction of labor. A prospective study was conducted at the University of Kansas Medical Center where we enrolled term pregnant women undergoing induction of labor. Exclusion criteria included diagnosis of preeclampsia, multiple gestations, and known fetal anomalies. After obtaining written informed consent, nursing staff obtained a maternal blood sample when placing the IV. Subjects were provided with a State-Trait Anxiety Inventory self-questionnaire to assess anxiety levels. Additional blood samples were collected from the IV hourly over the course of 3h. Fetal heart rate baselines were recorded every 30 minutes. Maternal serum catecholamines (epinephrine (E) and norepinephrine (NE)) were measured at each time point according to manufacturer protocol. The change in fetal heart rate was plotted against the change in catecholamine levels over time. Forty-three women were enrolled; 39 had enough samples to analyze. The mean fetal heart rate over the 3h declined incrementally from 138.1±8 to 135.6±7 beats per minute (bpm). The mean maternal serum NE decreased from 5.46±3.6 pmol/L to 4.65±2.3 pmol/L over the first 2h but increased to 5.27±3.4 pmol/L at hour 3. Maternal serum E was undetectable and excluded from analysis. The State-Trait Anxiety Inventory questionnaire showed a mean state anxiety score of 34.5±10 and mean trait anxiety score of 29.9±6, consistent with mild anxiety. Serum catecholamine levels do not appear to have a significant impact on baseline fetal heart rate in women experiencing mild levels of anxiety during an induction of labor. None of these women were in active labor during the study period. Future study will examine similar variables in women admitted in early active labor.

Is spaceflight-induced immune dysfunction linked to systemic changes in metabolism?

The Space Shuttle Atlantis launched on its final mission (STS-135) on July 8, 2011. After just under 13 days, the shuttle landed safely at Kennedy Space Center (KSC) for the last time. Female C57BL/6J mice flew as part of the Commercial Biomedical Testing Module-3 (CBTM-3) payload. Ground controls were maintained at the KSC facility. Subsets of these mice were made available to investigators as part of NASA’s Bio-specimen Sharing Program (BSP). Our group characterized cell phenotype distributions and phagocytic function in the spleen, catecholamine and corticosterone levels in the adrenal glands, and transcriptomics/metabolomics in the liver. Despite decreases in most splenic leukocyte subsets, there were increases in reactive oxygen species (ROS)-related activity. Although there were increases noted in corticosterone levels in both the adrenals and liver, there were no significant changes in catecholamine levels. Furthermore, functional analysis of gene expression and metabolomic profiles suggest that the functional changes are not due to oxidative or psychological stress. Despite changes in gene expression patterns indicative of increases in phagocytic activity (e.g. endocytosis and formation of peroxisomes), there was no corresponding increase in genes related to ROS metabolism. In contrast, there were increases in expression profiles related to fatty acid oxidation with decreases in glycolysis-related profiles. Given the clear link between immune function and metabolism in many ground-based diseases, we propose a similar link may be involved in spaceflight-induced decrements in immune and metabolic function.

Real-time monitoring of electrically evoked catecholamine signals in the songbird striatum using in vivo fast-scan cyclic voltammetry

Fast-scan cyclic voltammetry is a powerful technique for monitoring rapid changes in extracellular neurotransmitter levels in the brain. In vivo fast-scan cyclic voltammetry has been used extensively in mammalian models to characterize dopamine signals in both anesthetized and awake preparations, but has yet to be applied to a non-mammalian vertebrate. The goal of this study was to establish in vivo fast-scan cyclic voltammetry in a songbird, the European starling, to facilitate real-time measurements of extracellular catecholamine levels in the avian striatum. In urethane-anesthetized starlings, changes in catecholamine levels were evoked by electrical stimulation of the ventral tegmental area and measured at carbon–fiber microelectrodes positioned in the medial and lateral striata. Catecholamines were elicited by different stimulations, including trains related to phasic dopamine signaling in the rat, and were analyzed to quantify presynaptic mechanisms governing exocytotic release and neuronal uptake. Evoked extracellular catecholamine dynamics, maximal amplitude of the evoked catecholamine signal, and parameters for catecholamine release and uptake did not differ between striatal regions and were similar to those determined for dopamine in the rat dorsomedial striatum under similar conditions. Chemical identification of measured catecholamine by its voltammogram was consistent with the presence of both dopamine and norepinephrine in striatal tissue content. However, the high ratio of dopamine to norepinephrine in tissue content and the greater sensitivity of the carbon–fiber microelectrode to dopamine compared to norepinephrine favored the measurement of dopamine. Thus, converging evidence suggests that dopamine was the predominate analyte of the electrically evoked catecholamine signal measured in the striatum by fast-scan cyclic voltammetry. Overall, comparisons between the characteristics of these evoked signals suggested a similar presynaptic regulation of dopamine in the starling and rat striatum. Fast-scan cyclic voltammetry thus has the potential to be an invaluable tool for investigating the neural underpinnings of behavior in birds.

Plasma catecholamine levels before and after paroxetine treatment in patients with panic disorder

Catecholamines such as norepinephrine, epinephrine, and dopamine are closely related to the autonomic nervous system, suggesting that panic disorder may involve elevated catecholamine levels. This study investigated basal and posttreatment catecholamine levels in patients with panic disorder. A total of 29 patients with panic disorder and 23 healthy controls participated in the study. Panic disorder patients received paroxetine treatment for 12 weeks after clinical tests and examination had been conducted. We investigated the difference in basal levels of catecholamine and measured the changes in catecholamine levels before and after drug treatment in panic disorder patients. The basal plasma epinephrine (48.87±6.18pg/ml) and dopamine (34.87±3.57pg/ml) levels of panic disorder patients were significantly higher than those (34.79±4.72pg/ml and 20.40±3.53pg/ml) of the control group. However, basal plasma norepinephrine levels did not show statistically significant differences between patients and controls. After drug therapy, plasma catecholamine levels were nonsignificantly decreased and norepinephrine levels showed a tendency toward a decrease that did not reach significance. In conclusion, this study suggests the possibility of a baseline increase of plasma catecholamine levels and activation of sympathetic nervous systems in patients with panic disorder which may normalize after treatment with paroxetine.

28. The effects of the spaceflight environment on stress pathways

In previous experiments, we have shown that spaceflight can alter leukocyte and lymphocyte population distributions and mitogen-induced cytokine expression. We hypothesize that these changes are a result of flight-induced physiological and psychological stress. On July 8, 2011, age- and weight-matched, female C57BL/6J mice were placed into Animal Enclosure Modules (AEMs) and flown on the Space Shuttle Atlantis (STS-135) for 13 days ( N = 6–7). Ground controls were housed at the Space Life Science Laboratory (SLSL) at Kennedy Space Center (KSC). Ground AEM control mice were placed into the same hardware used in flight and environmental parameters such as temperature and CO2 levels were matched as closely as possible based on 48 h delayed telemetry data ( N = 12–13). Vivarium control mice were housed in regular shoebox cages ( N = 4). Mice were euthanized and dissected within 3–5 h of landing. Adrenals were removed, snap frozen in liquid N2, and shipped on ice back to Loma Linda University via overnight courier for analysis. Although corticosterone levels were slightly elevated in spaceflight mice, with a corresponding decrease in phosphorylated adrenocorticotropic hormone (ACTH) levels, these changes were not enough to reach significance. Similarly, there were no significant changes in catecholamine levels. This suggests that there is no significant impact of spaceflight on stress pathways. However, closer examination of the data indicates that the circadian rhythm may have masked the overall effect of spaceflight.

Cloning and expression analysis of tyrosine hydroxylase and changes in catecholamine levels in brain during ontogeny and after sex steroid analogues exposure in the catfish, Clarias batrachus

Tyrosine hydroxylase (Th) is the rate-limiting enzyme for catecholamine (CA) biosynthesis and is considered to be a marker for CA-ergic neurons, which regulate the levels of gonadotropin-releasing hormone in brain and gonadotropins in the pituitary. In the present study, we cloned full-length cDNA of Th from the catfish brain and evaluated its expression pattern in the male and female brain during early development and after sex-steroid analogues treatment using quantitative real-time PCR. We measured the CA levels to compare our results on Th. Cloned Th from catfish brain is 1.591kb, which encodes a putative protein of 458 amino acid residues and showed high homology with other teleosts. The tissue distribution of Th revealed ubiquitous expression in all the tissues analyzed with maximum expression in male and female brain. Copy number analysis showed two-fold more transcript abundance in the female brain when compared with the male brain. A differential expression pattern of Th was observed in which the mRNA levels were significantly higher in females compared with males, during early brain development. CAs, l-3,4-dihydroxyphenylalanine, dopamine, and norepinephrine levels measured using high-performance liquid chromatography with electrochemical detection in the developing male and female brain confirmed the prominence of the CA-ergic system in the female brain. Sex-steroid analogue treatment using methyltestosterone and ethinylestradiol confirmed our findings of the differential expression of Th related to CA levels.

Music: a better alternative than pain?

Over 7 million people suffer from chronic pain in the UK1 and GPs will encounter the difficulties of relieving their symptoms on a daily basis. Music, as well as being known to have emotional, mental, and spiritual benefits since Biblical times, has been investigated for its possible analgesic properties. A large number of studies have provided considerable evidence that music can decrease pain levels. Pain relief may occur by the release of endorphins or changes in catecholamine levels or, as patients are distracted by memories away from their pain.2,3 A Cochrane review4 recognised that there is great diversity in music and pain studies and experimentally-induced pain cannot fully mimic the experience of chronic pain.5 Not only do complex psychological and social factors influence a person’s pain, but studies are …

Catecholamine levels in groundwater and stream amphipods and their response to temperature stress

Temperature stress in invertebrates is known to be reflected by changes in catecholamine levels. However, the mechanisms of stress response are not fully understood. Groundwater and surface water amphipods are expected to be differently adapted to temperature elevations due to the different temperature regimes in their habitats and consequently, show a different stress response. No data have been published so far regarding the effects of stress on catecholamine patterns in groundwater invertebrates and accordingly, comparisons with surface water fauna are also missing. In this study, we compared the average catecholamine levels in two taxonomically related amphipod species: Niphargus inopinatus, living in groundwater with constant water temperatures throughout the year, and Gammarus pulex, a surface water stream amphipod frequently exposed to diurnal and seasonal temperature fluctuations. Furthermore, we tracked the immediate changes in whole-animal catecholamine levels in response to heat stress in both species. Pronounced differences in the catecholamine levels of the two species became apparent, with the average dopamine (DA) level of N. inopinatus being almost 1000times higher than that in G. pulex. The noradrenaline (NA) concentrations in N. inopinatus were on average two orders of magnitude higher than in G. pulex, and for adrenaline (A), the difference constituted one order of magnitude. When exposed to short-term heat stress, both species showed a response in terms of catecholamine levels, but the observed patterns were different. In N. inopinatus, temperature stress was reflected by the appearance of adrenaline, while in G. pulex a significant increase in noradrenaline levels occurred in the treatment with the highest temperature elevation.

Streptozotocin Causes Pancreatic Beta Cell Failure via Early and Sustained Biochemical and Cellular Alterations

The morphological and biochemical changes that occur in the early phase of streptozotocin (STZ)-induced beta cell failure have not been characterized. The pancreas and plasma of rats treated with STZ were processed for morphological and biochemical parameters 1-24 h and 4 weeks after STZ treatment. Marked reduction in body weight was observed as early as 3 h post STZ treatment and hyperglycemia coupled with hypoinsulinaemia appeared in rats 1 h after treatment with STZ. Hyperglycemia, hyperglucagonemia and hypoinsulinemia became permanent 24 h after STZ treatment. The number of insulin-positive cells decreased significantly (p<0.05) at 24 h after STZ treatment with a concomitant increase in the number of glucagon-immunoreactive cells. Electron microscopy showed coalescing of beta cell granules 18 h after STZ treatment. A near to complete degranulation of beta cells settled at 21 h after STZ administration. The pancreatic tissue and plasma levels of adrenaline and noradrenaline increased significantly (p<0.004: pancreatic tissue; p<0.04: plasma) 3 h after STZ treatment and remained high after a reduction at 6 h post STZ treatment. The pancreatic tissue and plasma levels of 5-HIAA decreased significantly (p<0.002 pancreatic tissue; p<0.04: plasma) 1 h after STZ treatment and remained low after a reduction at 6-9 h post STZ treatment. STZ elicited significant dose-dependent increases in insulin secretion from the isolated pancreas. The early changes in catecholamine level may be used in screening and follow-up studies on diabetes mellitus.

The Importance of Vanillylmandelic Acid Determination in Opiate Users

The Importance of Vanillylmandelic Acid Determination in Opiate UsersAlthough knowledge about the etiology of heroin dependence is rather poor, it is known that the influence of opiates on the opioid, adrenergic and indirectly of GABA on the dopaminergic receptors leads to changes of catecholamine levels in brain structures, which are supposed to be essential in explaining the etiology of the opioid dependence. It is well-known that by analyzing catecholamine, we get vanillylmandelic acid (VMA), which is found in the urine as a final product. Thus, by an indirect determination of VMA it is also possible to define the catecholamine concentration in the brain, which is the aim of this study. This prospective study included 51 dependent heroin users divided into 3 groups, depending on the length of the medical treatment with a conventional detox method (without treatment, second day of the treatment, and after the 10th day of treatment) as well as a control group consisting of 20 healthy subjects. We used the Pissano method chromatographic-spectrophotometric determination - for estimating the level of vanillylmandelic acid, and a scale for defining the severity of symptoms of the withdrawal syndrome (WS). The results showed that the highest average values of the urinary level of VMA were found in the subjects in withdrawal crisis with a high WS scale score in comparison with the other examined groups (statistically significant) as a result of the high adrenergic level. The average score on the scale of depression was high in the subjects in withdrawal crisis where we also found low values of the VMA urinary level. Being aware of the neurobiology of heroin dependence is of great importance for finding new pharmacological treatments for heroin addiction.

Concentrations of Catecholamines in the Median Eminence of Sheep after Superovulation

The effect of hormonal superovulation preparations of FSH (450 IU) or PMSG (1500 IU), on concentration of catecholamines (dopamine, norepinephrine and epinephrine) was studied in the oestrus period using radioenzymatic methods in the median eminence of the sheep. The administration of FSH caused a significant increase in the concentrations of norepinephrine (NE) and epinephrine (EPI) in the median eminence (ME) of sheep (p &lt; 0.01 and p &lt; 0.05, respectively). The comparison of the effect of hormonal preparations on the changes in catecholamine levels showed that the effect of FSH was observed mostly in eminentia mediana of sheep. We propose that the given changes in concentrations of catecholamines in the median eminence of sheep after administration of PMSG or FSH are related to steroids after hormonal stimulation.

Effects of controlled hypoglycaemia on cardiac repolarisation in patients with type 1 diabetes

Nocturnal hypoglycaemia may contribute to sudden death in diabetic patients. However, it is not well known why hypoglycaemia makes these patients prone to death. We assessed the effects of controlled hypoglycaemia on cardiac repolarisation using novel electrocardiographic descriptors of T-wave and QRS complex morphology in 16 type 1 diabetic patients and eight healthy counterparts. Several electrocardiographic variables characterising repolarisation were analysed from digitised 12-lead electrocardiograms during a euglycaemic and a hypoglycaemic clamp. Hypoglycaemia did not result in significant changes either in the QT interval corrected for heart rate by the nomogram method or in QT dispersion. However, the morphology of the T-wave changed significantly during hypoglycaemia. The T-wave amplitude and area in precordial leads decreased significantly in both groups (p<0.05 to p<0.001). The spatial QRS-T angle (total cosine R to T) (p<0.05) and the height and the width of the T-wave loop (p<0.05 and p<0.01, respectively) were also reduced in the diabetic patients. The changes in the repolarisation parameters did not exhibit any significant association with changes in catecholamine levels or in heart rate variability in either group. Hypoglycaemia results in distinct alterations in cardiac repolarisation, which may increase the vulnerability to arrhythmic events.

Protective Effects of Selenium and Zinc on Changes in Catecholamine Levels of Brain Regions in Lead Intoxified Rat

Lead is a common environmental toxic element for almost all biological systems. The nervous system is the primary target for the lead exposure. In the past few years, increasing considerations have been given to investigate the interaction occurring between toxic metals and some essential metals including Se and Zn with Pb. It has been shown that some trace elements could reverse the toxicity of lead on tissue functions. In this study the protective effects of Zn and Se on lead toxicity were investigated. Results of short time study showed that, intrapritoneal administration of Pb (13.5 mg kg(-1)) daily for 2 weeks reduced the catecholamine levels of cortex by 25, mid-Brain by 21 and cerebellum by 25.6%, respectively. Administration of the same amount of lead in combination with either Zn (0.5 mg kg(-1)) or Se (0.4 mg kg(-1)) reduced catecholamine levels of cortex by 8.3 and 18.3, mid-brain by 6, 10.9 and cerebellum 23, 6% respectively. Daily administration of lead alone (4 mg kg(-1)) for 60 days reduced catecholamine level of cortex by 27.4 and mid-Brain by 47.8 and cerebellum by 39%, respectively. When the same amount of lead in combination with Zinc (0.5 mg kg(-1)) and/or Se (0.4 mg kg(-1)) was administration daily for 60 days, results showed that catecholamine level of cortex was reduced by 9, 20 and mid-brain by 22.6, 29 and cerebellum 25, 16%, respectively. It is concluded that lead reduced catecholamine levels in different brain regions and Zn or Se might be able to reverse this reduction and protect brain function to some extent from lead toxicity.