Synthesis of ultrasmall cerium oxide nanoparticles in deep eutectic solvent and their application in an electrochemical sensor to detect dopamine in biological fluid.

A solvothermal synthesis of ultrasmall cerium oxide nanoparticles (USCeOxNPs) with an average size of 0.73 ± 0.07 nm using deep eutectic solvent (DES) as a stabilizing medium at a temperature of 90 ºC is reported. Transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) were used to morphologically characterize the USCeOxNPs. These revealed approximately spherical shapes with emission lines characteristic of cerium. Selected area electron diffraction (SAED) was used to determine the crystalline structure of the cerium oxide nanoparticles (CeO2NPs), revealing the presence of crystalline cubic structures. The USCeOxNPs-DES/CB film was characterized by scanning electron microscopy (SEM), which demonstrated the spherical characteristic of CB with layers slightly covered by DES residues. DES was characterized by Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR), indicating its formation through hydrogen bonds between the precursors. An electrochemical sensor for dopamine (DA) determination in biological fluids was developed using the USCeOxNPs together with carbon black (CB). An enhanced current response was observed on DA voltammetric determination, and this can be attributed to the USCeOxNPs. This sensor displayed linear responses for DA in the range 5.0 × 10-7 mol L-1 to 3.2 × 10-4 mol L-1, with a limit of detection of 80 nmol L-1. Besides detectability, excellent performances were verified for repeatability and anti-interference. The sensor based on USCeOxNPs synthesized in DES in a simpler and environmentally friendly way was successfully applied to determine DA in biological matrix.

A LC-MS/MS method for the simultaneous determination of 6-cyanodopamine, 6-nitrodopamine, 6-nitrodopa, 6-nitroadrenaline and 6-bromodopamine in human plasma and its clinical application in patients with chronic kidney disease.

The aim of this study was to develop a high-performance liquid chromatography-tandem mass spectrometry method for the determination of 6-cyanodopamine, 6-nitrodopamine, 6-nitrodopa, 6-nitroadrenaline and 6-bromodopamine in human plasma samples. Strata-X 33 µm solid-phase extraction cartridges were used for the extraction of the catecholamines from human plasma samples. The catecholamines were separated in a 150 × 3 mm Shim-pack GIST C18-AQ column with 3 µm particle size, placed in an oven at 40°C and perfused with 82% mobile phase A (acetonitrile-H2O; 90:10, v/v) + 0.4% acetic acid and 18% mobile phase B (deionized H2O) + 0.2% formic acid at a flow rate of 340 µl/min in isocratic mode. The injected volume was 4 µl and the run lasted 4 min. The method was linear from 0.1 to 20 ng/ml and the lower limit of quantification was 0.1 ng/ml for all analytes. The method was applied to evaluate the plasma levels of catecholamines in plasma of patients with chronic kidney disease and allowed the detection for the first time of circulating levels of the novel catecholamines 6-bromodopamine and 6-cyanodopamine.

Non-enzymatic biosensor based on F,S-doped carbon dots/copper nanoarchitecture applied in the simultaneous electrochemical determination of NADH, dopamine, and uric acid in plasma.

This work presents the synthesis and characterization of an innovative F,S-doped carbon dots/CuONPs hybrid nanostructure obtained by a direct mixture between F,S-doped carbon dots obtained electrochemically and copper nitrate alcoholic solution. The hybrid nanostructures synthesized were characterized by absorption spectroscopy in the Ultraviolet region (UV-vis), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and different electrochemical techniques. The fluoride and sulfur-doped carbon dots/CuONPs nanostructures were used to prepare a non-enzymatic biosensor on a printed carbon electrode, exhibiting excellent electrocatalytic activity for the simultaneous determination of NADH, dopamine, and uric acid in the presence of ascorbic acid with a detection limit of 20, 80, and 400 nmol L-1, respectively. The non-enzymatic biosensors were also used to determine NADH, dopamine, and uric acid in plasma, and they did not suffer significant interference from each other.

Design of novel, simple, and inexpensive 3D printing-based miniaturized electrochemical platform containing embedded disposable detector for analytical applications.

This paper describes the development of a novel, simple, and inexpensive electrochemical device containing an integrated and disposable three-electrode system for detection. The base of this platform consists on a PDMS structure containing microchannels which were prototyped using 3D-printed molds. Pencil graphite leads were inserted into these microchannels and utilized as working, counter and reference electrodes in a novel design. Morphological analysis and electrochemical experiments with benchmark redox probes were carried out in order to evaluate the performance and characterize the miniaturized device proposed. Even using inexpensive materials and a simple fabrication protocol, the electrochemical platform developed provided good repeatability and reproducibility over a low cost (ca. $2 per device), acceptable lifetime (ca. 250 voltammetric runs) and extremely reduced consumption of samples and reagents (order of µL). As proof of concept, the analytical feasibility of the platform was investigated through the simultaneous determination of dopamine (DOPA) and acetaminophen (AC). The two analytes showed linear dependence on the concentration range from 1 to 15 µM and the LODs achieved were 0.21 µM for DOPA and 0.29 µM for AC. Moreover, the platform was successfully applied on the determination of DOPA and AC in spiked blood serum and urine samples. The results obtained with the device described here were better than some reports in literature that use more costly electrodic materials and complex modification steps for the detection of the same analytes.

Exercise activates vagal induction of dopamine and attenuates systemic inflammation.

Physical exercise is one of the most important factors improving quality of life, but it is not feasible for patients with morbidity or limited mobility. Most previous studies focused on high-intensity or long-term exercise that causes metabolic stress or physiological adaption, respectively. Here, we studied how moderate-intensity swimming affects systemic inflammation in 6-8 week old C57BL/6J male mice during endotoxemia. One-hour swimming prevented hypokalemia, hypocalcemia, attenuated serum levels of inflammatory cytokines, increased anti-inflammatory cytokines but affected neither IL6 nor glycemia before or after the endotoxic challenge. Exercise attenuated serum TNF levels by inhibiting its production in the spleen through a mechanism mediated by the subdiaphragmatic vagus nerve but independent of the splenic nerve. Exercise increased serum levels of dopamine, and adrenalectomy prevented the potential of exercise to induce dopamine and to attenuate serum TNF levels. Dopaminergic agonist type-1, fenoldopam, inhibited TNF production in splenocytes. Conversely, dopaminergic antagonist type-1, butaclamol, attenuated exercise control of serum TNF levels. These results suggest that vagal induction of dopamine may contribute to the anti-inflammatory potential of physical exercise.

Effects of Glutamine and Alanine Supplementation on Central Fatigue Markers in Rats Submitted to Resistance Training.

Recent evidence suggests that increased brain serotonin synthesis impairs performance in high-intensity intermittent exercise and specific amino acids may modulate this condition, delaying fatigue. This study investigated the effects of glutamine and alanine supplementation on central fatigue markers in rats submitted to resistance training (RT). Wistar rats were distributed in: sedentary (SED), trained (CON), trained and supplemented with alanine (ALA), glutamine and alanine in their free form (G + A), or as dipeptide (DIP). Trained groups underwent a ladder-climbing exercise for eight weeks, with progressive loads. In the last 21 days, supplementations were offered in water with a 4% concentration. Albeit without statistically significance difference, RT decreased liver glycogen, and enhanced the concentrations of plasma glucose, free fatty acids (FFA), hypothalamic serotonin, and ammonia in muscle and the liver. Amino acids affected fatigue parameters depending on the supplementation form. G + A prevented the muscle ammonia increase by RT, whereas ALA and DIP augmented ammonia and glycogen concentrations in muscle. DIP also increased liver ammonia. ALA and G + A reduced plasma FFA, whereas DIP increased this parameter, free tryptophan/total tryptophan ratio, hypothalamic serotonin, and the serotonin/dopamine ratio. The supplementations did not affect physical performance. In conclusion, glutamine and alanine may improve or impair central fatigue markers depending on their supplementation form.

Simultaneous determination of levodopa, carbidopa, entacapone, tolcapone, 3-O-methyldopa and dopamine in human plasma by an HPLC-MS/MS method.

BACKGROUND: In this study, we developed and validated a HPLC-MS/MS method capable of simultaneously determining levodopa, carbidopa, entacapone, tolcapone, 3-O-methyldopa and dopamine in human plasma. RESULTS & METHODOLOGY: Chromatographic separation was achieved using a C8 column with a mobile phase consisting of a gradient of water and acetonitrile:methanol (90:10 v/v), both containing 0.1% formic acid. The developed method was selective, sensitive (LD<7.0 ng ml(-1)), linear (r>0.99), precise (RSD<11.3%), accurate (RE<11.8%) and free of residual and matrix effects. The developed method was successfully applied in plasma patients with Parkinson's disease using Stalevo®. CONCLUSION: The new method can be used for the clinical monitoring of these substances and applied to adjustments in drug dosages.

Melatonin and dopamine as biomarkers to optimize treatment in phenylketonuria: effects of tryptophan and tyrosine supplementation.

OBJECTIVE: To determine whether additional supplementation of tryptophan (Trp) and tyrosine (Tyr) improve serotonin and dopamine metabolism in individuals with phenylketonuria treated with large neutral amino acid (LNAA) tablets. STUDY DESIGN: Ten adult individuals with phenylketonuria participated in a randomized, double-blind, placebo-controlled cross-over study consisting of three 3-week phases: washout, treatment with LNAA tablets plus supplementation with either Trp and Tyr tablets or placebo, and LNAA tablets plus the alternate supplementation. An overnight protocol to measure blood melatonin, a serotonin metabolite in the pinealocytes, and urine 6-sulfatoxymelatonin and dopamine in first-void urine specimens was conducted after each phase. RESULTS: Serum melatonin and urine 6-sulfatoxymelatonin and dopamine levels were increased in the LNAA phase (LNAA plus placebo) compared with the washout phase. Serum melatonin and urine 6-sulfatoxymelatonin were not increased in the active phase (LNAA plus Trp + Tyr) compared with the LNAA phase, although plasma Trp:LNAA was increased compared with the LNAA phase. Among 7 subjects with a plasma Trp/LNAA >0.03, a negative correlation between urine 6-sulfatoxymelatonin and plasma phenylalanine levels was observed (r = -0.072). Urine dopamine levels and plasma Tyr:LNAA were increased in the active phase compared with the LNAA phase. CONCLUSION: Melatonin levels were not increased with the higher dose of Trp supplementation, but dopamine levels were increased with the higher dose of Tyr supplementation. Serotonin synthesis appears to be suppressed by high phenylalanine levels at the Trp hydroxylase level.

Effect of intravenous lidocaine associated with amitriptyline on pain relief and plasma serotonin, norepinephrine, and dopamine concentrations in fibromyalgia.

OBJECTIVE: The objective of this study was to evaluate the effect of intravenous lidocaine combined with amitriptyline on pain relief and plasma serotonin, norepinephrine, and dopamine levels. METHODS: A prospective, randomized, double-blind comparative study was conducted in 30 patients. All patients received 25 mg amitriptyline; monotherapy group (n=15) received 125 mL saline, and combined therapy group (n=15) received 240 mg lidocaine in 125 mL saline once a week for 4 weeks. Serotonin, norepinephrine, and dopamine were measured in plasma at time zero (T0) and after 4 weeks (T4). Pain intensity was rated on a numerical scale at the beginning of the study and weekly for 4 weeks. RESULTS: All patients were females and the mean age was 44.7±10.5 years for monotherapy group and 40.9±11.6 years for combined therapy group. No difference in pain intensity at baseline was observed between groups, with a decrease after treatment in monotherapy group (T0: 7.0±1.2 and T4: 4.0±2.1) and in combined therapy group (T0: 7.6±0.8 and T4: 4.1±2.3). Plasma serotonin and norepinephrine levels were similar in the 2 groups at T0 and T4. An increase in dopamine levels was observed in monotherapy group from the beginning to the end of treatment. CONCLUSIONS: Combined administration of 240 mg intravenous lidocaine (once a week) and 25 mg amitriptyline for 4 weeks did not modify pain intensity or plasma serotonin, norepinephrine, or dopamine concentrations in fibromyalgia patients.

Oxidative stress, progressive damage in the substantia nigra and plasma dopamine oxidation, in rats chronically exposed to ozone.

The purpose of our work was to determine the effects of oxidative stress on the neurodegeneration process in the substantia nigra, and to evaluate dopamine-oxidation metabolites in the plasma using a cyclic voltammetry (CV) technique. We have also studied the correlation between the increases in oxidized dopamine-species levels with the severity of lipid-peroxidation in the plasma. Sixty-four male Wistar rats were divided into four experimental groups and received air (Group I, control) or ozone (0.25 ppm) daily by inhalation for 4h for 15 (Group II), 30 (Group III), and 60 (Group IV) days. The brains were processed for immunohistochemical location of dopamine and p53 in the substantia nigra. Plasma collected from these animals was assayed for oxidized dopamine products using CV and lipid-peroxidation levels were measured. Our results indicate that chronic exposure to low O(3) doses causes that the number of dopaminergic neurons decreased, and p53-immunoreactive cells increases until 30 days; which was a function of the time of exposure to ozone. Oxidative stress produces a significant increase in the levels of the dopamine quinones (DAQs) that correlated well (r=0.962) with lipid peroxides in the plasma during the study period. These results suggest that DAQ could be a reliable, peripheral oxidative indicator of nigral dopaminergic damage in the brain.

Effects of amantadine on circulating neurotransmitters in healthy subjects.

Considering that glutamatergic axons innervate the C1(Ad) medullary nuclei, which are responsible for the excitation of the peripheral adrenal glands, we decided to investigate catecholamines (noradrenaline, adrenaline and dopamine) plus indolamines (plasma serotonin and platelet serotonin) at the blood level, before and after a small oral dose of amantadine, a selective NMDA antagonist. We found that the drug provoked a selective enhancement of noradrenaline plus a minimization of adrenaline, dopamine, plasma serotonin and platelet serotonin circulating levels. Significant enhancement of diastolic blood pressure plus reduction of systolic blood pressure and heart rate paralleled the circulating parameter changes. The above findings allow us to postulate that the drug was able to enhance the peripheral neural sympathetic activity. Minimization of both adrenal sympathetic and parasympathetic activities was also registered after the amantadine challenge. The above findings supported the postulation that this drug should be a powerful therapeutic tool for treating diseases affected by adrenal sympathetic hyperactivity.

Effect of sildenafil (Viagra®) on the genital reflexes of paradoxical sleep-deprived male rats

Since there is evidence that paradoxical sleep deprivation (PSD) elicits penile erection (PE) and ejaculation (EJ), and that the erectile response of rats is mediated by nitric oxide, the present study sought to extend the latter finding by assessing the effects of sildenafil on the genital reflexes of male Wistar rats subjected to PSD. We also determined the influence of sildenafil on hormone concentrations. In the first experiment, sildenafil at doses ranging from 0.08 to 0.32 mg/kg was administered intraperitoneally to rats that had been deprived of sleep for 4 days and to home cage controls (N = 8-10/group). The frequency of PE and EJ was measured for 60 min. PSD alone induced PE in 50 percent of the animals; however, a single injection of sildenafil did not significantly increase the percentage of rats displaying PE compared to PSD-saline or to home cage groups. PSD alone also induced spontaneous EJ, but this response was not potentiated by sildenafil in the dose range tested. Testosterone concentrations were significantly lower in PSD rats (137 ± 22 ng/dL) than in controls (365 ± 38 ng/dL), whereas progesterone (0.9 ± 0.1 vs 5.4 ± 1 ng/mL) and plasma dopamine (103.4 ± 30 vs 262.6 ± 77 pg/mL) increased. These changes did not occur after sildenafil treatment. The data show that although sildenafil did not alter the frequency of genital reflexes, it antagonized hormonal (testosterone and progesterone) and plasma dopamine changes induced by PSD. The stimulation of the genital reflexes by sildenafil did not result in potentiating effects in PSD rats.

Effect of sildenafil (Viagra) on the genital reflexes of paradoxical sleep-deprived male rats.

Since there is evidence that paradoxical sleep deprivation (PSD) elicits penile erection (PE) and ejaculation (EJ), and that the erectile response of rats is mediated by nitric oxide, the present study sought to extend the latter finding by assessing the effects of sildenafil on the genital reflexes of male Wistar rats subjected to PSD. We also determined the influence of sildenafil on hormone concentrations. In the first experiment, sildenafil at doses ranging from 0.08 to 0.32 mg/kg was administered intraperitoneally to rats that had been deprived of sleep for 4 days and to home cage controls (N = 8-10/group). The frequency of PE and EJ was measured for 60 min. PSD alone induced PE in 50% of the animals; however, a single injection of sildenafil did not significantly increase the percentage of rats displaying PE compared to PSD-saline or to home cage groups. PSD alone also induced spontaneous EJ, but this response was not potentiated by sildenafil in the dose range tested. Testosterone concentrations were significantly lower in PSD rats (137 +/- 22 ng/dL) than in controls (365 +/- 38 ng/dL), whereas progesterone (0.9 +/- 0.1 vs 5.4 +/- 1 ng/mL) and plasma dopamine (103.4 +/- 30 vs 262.6 +/- 77 pg/mL) increased. These changes did not occur after sildenafil treatment. The data show that although sildenafil did not alter the frequency of genital reflexes, it antagonized hormonal (testosterone and progesterone) and plasma dopamine changes induced by PSD. The stimulation of the genital reflexes by sildenafil did not result in potentiating effects in PSD rats.

Reduced maximal oxygen consumption and overproduction of proinflammatory cytokines in athletes.

OBJECTIVE: It was the aim of this study to evaluate whether chronic pain in athletes is related to performance, measured by the maximum oxygen consumption and production of hormones and cytokines. METHODS: Fifty-five athletes with a mean age of 31.9 +/- 4.2 years engaged in regular competition and showing no symptoms of acute inflammation, particularly fever, were studied. They were divided into 2 subgroups according to the occurrence of pain. Plasma concentrations of adrenaline, noradrenaline, cortisol, prolactin, growth hormone and dopamine were measured by radioimmunoassay, and the production of the cytokines interleukin (IL)-1, IL-2, IL-4, IL-6, tumor necrosis factor-alpha, interferon-alpha and prostaglandin E(2) by whole-blood culture. Maximal oxygen consumption was determined during an incremental treadmill test. RESULTS: There was no change in the concentration of stress hormones, but the athletes with chronic pain showed a reduction in maximum oxygen consumption (22%) and total consumption at the anaerobic threshold (25%), as well as increased cytokine production. Increases of 2.7-, 8.1-, 1.7- and 3.7-fold were observed for IL-1, IL-2, tumor necrosis factor-alpha and interferon-alpha, respectively. CONCLUSIONS: Our data show that athletes with chronic pain have enhanced production of proinflammatory cytokines and lipid mediators and reduced performance in the ergospirometric test.

Plasma catecholamines and blood volume in native Andeans during hypoxia and normoxia.

Plasma catechols and blood volume were measured in 20 male, native high-altitude residents of Cerro de Pasco, Peru (4338 m), while hypoxic and subsequently while normoxic at sea level. Ten subjects were healthy controls,with hematocrits lower than 61%, and ten had chronic mountain sickness (CMS), a syndrome of maladaptation to altitude, characterized by polycythemia (hematocrit > 61%), profound hypoxemia, and neurologic symptoms. The main aim of the study was to evaluate the chronic effects of hypoxia on plasma catechols and on blood volume, by studying these parameters during hypoxia at high altitude (HA) and shortly after exposure to normoxia at sea level (SL). Subjects were first studied at HA in their habitual hypoxic environment, and measurements were repeated within 4 hours of arrival at SL (Lima, Peru, 150 m). All subjects had higher plasma norepinephrine (NE), dopamine (DA), and dihydroxyphenylglycol (DHPG) levels in HA (NE in controls and CMS: 414+/-47 and 514+/-35 pg/mL; DA: 9+/-1 and 13+/-1 pg/mL, DHPG: 817+/-48 and 972+/-77 pg/mL) than at SL (NE: 164+/-9 and 243+/-28 pg/mL; DA: 4+/-0.5 and 5+/-1 pg/mL DHPG: 502+/-23 and 649+/-39 pg/mL). Group differences were statistically significant only for NE in the CMS group. Plasma volume was higher in HA in both groups (p<0.05); red cell volume was higher in HA only in the CMS group. The results indicate sympathetic nervous stimulation by chronic ambient hypoxia at altitude in Andean natives, independent of maladaptation to their native environment.

Altered dopamine levels induced by the parasite Profilicollis antarcticus on its intermediate host, the crab Hemigrapsus crenulatus.

A serotonergic pathway is apparently involved in parasite-host interactions. Previous studies conducted in our laboratory showed increased rates in oxygen consumption and alterations in body posture in the crab Hemigrapsus crenulatus parasitized by the acanthocephalan, Profilicollis antarcticus. Such changes may be related to the functions described for biogenic amines in crustaceans. During the infective stage the acanthocephalans live freely in the hemocelomic cavity, suggesting that the possible alteration induced by biogenic amines may be related to their neurohormonal function in crustaceans. To test whether the presence of P. antarcticus produced neurohormonal changes in its intermediate host, H. crenulatus, we analyzed serotonin and dopamine levels in the host using HPLC with electrochemical detection. Two groups of 11 female crabs were studied; one group was artificially inoculated with two cystacanths while the other was used as the control. Our results show a dramatic increase in hemolymph dopamine, but not serotonin in H. crenulatus parasitized by the acanthocephalan P. antarcticus. Our results, along with those reported by Maynard (1996), suggest a parasite-specific strategy involved in the behavior alteration caused by the acanthocephalans on their intermediate host. The use of a biogenic amine as a mechanism of interaction by the parasites gives them an endless number of alternative potential actions on their intermediate hosts.

[Therapy with dehidroepiandrosterone improves symptoms in perimenopausal women]. / El tratamiento con dehidroepiandrosterona mejora los síntomas en las mujeres perimenopáusicas.

BACKGROUND: Depressive symptoms that occur with the onset of menopause are accompanied by changes in circulating neurotransmitters levels; these biochemical variations are considered to cause psychoemotional symptoms. OBJECTIVE: To assess the effect of DHEAsupplementation and its efficacy for relieving symptoms of emotional and psychological distress, as well as the action on circulating neurotransmitters in perimenopausal women. PATIENTS AND METHODS: An open, comparative, clinical study included twenty perimenopausal women who received oral DHEA doses and ten women acted as comparison group. SETTING: the Endocrine Research Unit, Instituto Mexicano del Seguro Social, Mexico City. Interventions and main outcome measures consisted of oral DHEA doses of 50 mg/day for six months. Green scale for climacteric women and Quality of Life Menopause Scale (QUALMS) were used to measure emotional and psychological symptoms and well-being. Serum levels of DHEA-S, dopamine, serotonin, and beta-endorphin were quantified by specific assays at baseline and at the end of the treatment. RESULTS: Alleviation of psychoemotional symptoms was observed in all but 4 treated women. Baseline levels of serum DHEA-S, serotonin and beta-endorphin increased significantly (p < 0.001) from 2.1 +/- 0.5 to 8.3 +/- 2.1 micromol/L, 215.3 +/- 86.4 to 310.4 + 150.1 ng/mL, and from 9.8 +/- 2.1 to 16.2 +/- 7.1 pmol/L respectively (means +/- SE) after treatment. In contrast, dopamine levels were unchanged. CONCLUSIONS: DHEA relieved emotional and psychological symptoms, and elevated both serotonin and beta-endorphin levels in perimenopausal women.

Altered dopamine levels induced by the parasite Profilicollis antarcticus on its intermediate host, the crab Hemigrapsus crenulatus

A serotonergic pathway is apparently involved in parasite-host interactions. Previous studies conducted in our laboratory showed increased rates in oxygen consumption and alterations in body posture in the crab Hemigrapsus crenulatus parasitized by the acanthocephalan, Profilicollis antarcticus. Such changes may be related to the functions described for biogenic amines in crustaceans. During the infective stage the acanthocephalans live freely in the hemocelomic cavity, suggesting that the possible alteration induced by biogenic amines may be related to their neurohormonal function in crustaceans. To test whether the presence of P. antarcticus produced neurohormonal changes in its intermediate host, H. crenulatus, we analyzed serotonin and dopamine levels in the host using HPLC with electrochemical detection. Two groups of 11 female crabs were studied; one group was artificially inoculated with two cystacanths while the other was used as the control. Our results show a dramatic increase in hemolymph dopamine, but not serotonin in H. crenulatus parasitized by the acanthocephalan P. antarcticus. Our results, along with those reported by Maynard (1996), suggest a parasite-specific strategy involved in the behavior alteration caused by the acanthocephalans on their intermediate host. The use of a biogenic amine as a mechanism of interaction by the parasites gives them an endless number of alternative potential actions on their intermediate hosts.

Circulating neurotransmitters during the different wake-sleep stages in normal subjects.

We investigated the changes of circulating neurotransmitters during the wake-sleep cycle in order to find possible correlations with the activity of central neurocircuitry functioning. Noradrenaline (NA), adrenaline (Ad), dopamine (DA), platelet serotonin (p-5HT), plasma serotonin (f-5HT) and plasma tryptophan (TRP) were assessed during the morning (supine resting + 1-min orthostasis + 5-min exercise) and at night (supine resting + slow wave sleep (SWS) + REM sleep). Only NA increased in the plasma during short-lasting (1-min) orthostasis morning waking period. Both NA and Ad rose during moderate exercise. The nocturnal results demonstrated that whereas Ad dropped during the supine resting, NA did not fall until SWS period. Although DA did not show significant changes during the nocturnal test, the NA/DA ratio showed significant reduction. The analysis of correlations supports the postulation that this finding reflects the DA modulatory role on neural sympathetic activity. Both f-5HT and p-5HT values were lower during sleep cycle than wake periods. However, they showed progressive rises during sleep stages. Conversely, the f-5HT/p-5HT ratio showed significantly greater values during the SWS period than during supine resting and REM periods. These findings are consistent with the postulation that f-5HT/p-5HT ratio is positively associated with parasympathetic activity during the sleep-cycle. We concluded that the profile of sleep-cycle circulating neurotransmitters differs from that obtained during waking periods. According to the above, we attempted to correlate the profile of circulating neurotransmitters with the very well-known central neurocircuitry functioning during wake-sleep cycle, in experimental mammals.

Serotonin, serotonin 5-HT(1A) receptors and dopamine in blood peripheral lymphocytes of major depression patients.

There are increasing evidences of cell markers present in the immune and the nervous systems. These include neurotransmitter receptors and transporters. Serotonin receptor subtypes are related to depression and also have been shown to be present in certain cells of the immune system. In the present report, we determined the presence of 5-HT(1A) receptors by the binding of the selective agonist 8-hydroxy-2-(di-n-propyl-amino)tetralin in lymphocytes of peripheral blood isolated by Ficoll/Hypaque gradients from controls and depressed patients. The capacity of these receptors was around 24 fmol/10(6) cells in both groups of subjects, without significant difference among them. The affinity was in the nM range and either differ between controls and patients. Serotonin, 5-hydroxyindoleacetic acid, dopamine and 3,4-dihydroxyphenylacetic acid were determined by HPLC with electrochemical detector. There were no significant differences between controls and major depression patients in the values obtained for rich and poor platelet plasma or in the isolated cells. However, there was a reduction in serotonin turnover rate indicated by an increase in the ratio serotonin/5-hydroxyindoleacetic acid, but not in that of dopamine, in lymphocytes of major depression patients. Thus, there is a serotonergic dysfunction in immune circulating cells of major depression patients, without changes in the number of 5-HT(1A) receptors, although the coupling of these receptors to transduction mechanisms could be affected and may be related to the alteration of 5-HT turnover rate.