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Effects of paced coital stimulation on termination of estrus and brain indoleamine levels in female rats.

Serotonin (5-HT) and 5-hydroxy-indoleacetic acid (5-HIAA) levels were measured in brain regions of ovariectomized, steroid-primed rats at the end of behavioral estrus. At the onset of behavioral estrus three groups of rats received coital stimulation which included (1) mounts without penile intromission only, (2) temporally-controlled (paced) mounts with intromission, and (3) non-paced mounts with intromission. Within 12 hr after the initial treatment, sexual receptivity was significantly lower in females given paced intromissions than in the other two groups. Brain stem 5-HT and 5-HIAA concentrations were significantly higher in females which received intromissions, regardless of whether or not they were paced than in females given mounts only. Hypothalamic and cortical concentrations of 5-HT and 5-HIAA were equivalent in the two groups. These results suggest that the termination of behavioral estrus is not associated with increased metabolic activity in central serotonergic neurons.

Animals↗

A sensitive and rapid fluorimetric assay for monoamine oxidase utilizing high pressure liquid chromatography.

A rapid and sensitive assay for the measurement of monoamine oxidase (MAO) activity was developed. This method utilizes high pressure liquid chromatography with fluorescence excitation at 280 nm and detection of 330 nm at pH 5.0 of indoleacetic acid and 5-hydroxyindoleacetic acid, the deaminated products of two substrates for MAO, tryptamine, and serotonin, respectively. The assay allows for the complete separation of metabolites from either of the two substrates. The method has been used to determine MAO activity in the frontal cortex and caudate nucleus of rat brain using tryptamine and serotonin as substrates. The ease and rapidity of this assay make it sutable for use where routine enzyme determinations are required.

Animals↗

Serotonin and schizophrenia: correlations between serotonergic activity and schizophrenic motor behavior.

Increased serotonergic activity in animals has been associated with a variety of stereotyped motor behaviors. In addition, serotonin facilitates brainstem, reticular, and spinal motor neuronal activity implicated in the expression of these behaviors. This report presents positive correlations between both peripheral (platelet serotonin levels) and central (cerebrospinal concentrations of 5-hydroxy-indoleacetic acid) measures of serotonin metabolism and the symptom of peculiar or unusual mannerisms and posturing in schizophrenic patients. The findings are discussed in light of the animal behavioral correlates of increased serotonergic activity and the stereotyped affectomotor behavior seen in some schizophrenic patients.

Adult↗

Urinary indoleamines in Tourette syndrome patients with obsessive-compulsive characteristics.

Tourette syndrome patients with high levels of obsessive-compulsive symptoms were compared with patients without these symptoms on urinary measures of serotonin and its major metabolite, 5-hydroxyindoleacetic acid (5HIAA). Both groups were compared with normal controls, and it was hypothesized that patients with obsessive-compulsive symptoms would have lower levels of serotonin. Both groups of Tourette syndrome patients had lower levels than controls, but there was no difference between them. Obsessive symptoms were related to higher levels of 5HIAA and to a higher turnover of serotonin.

Adolescent↗

Urinary amines in adults with Tourette's syndrome.

Urinary amines and their metabolites were examined in 32 adults who met DSM-III-R diagnostic criteria for Tourette's Syndrome. These patients were compared with a control group that was of similar age and sexual representation. Analyses revealed significantly lower levels of 3-methoxy-4-hydroxyphenylglycol and serotonin as well as the metabolites of several "trace" amines including indoleacetic acid and m- and p-hydroxyphenylacetic acid. These findings persisted when Tourette's Syndrome patients taking medications were eliminated from the analyses. These data are consistent with reports of neurotransmitter abnormalities in children with Tourette's Syndrome. The differences in several trace amine metabolites suggest that the pathophysiology in this disorder is complex and involves a number of neurotransmitter and neuromodulator systems.

Adolescent↗

Effects of advancing age on hypothalamic neurotransmitter content and on basal and norepinephrine-stimulated LHRH release.

In order to elucidate possible mechanism(s) responsible for the age-related decline in LH secretion, basal and norepinephrine (NE)-stimulated LHRH release was measured from median eminence (ME) fragments of 4-, 11-, 18- and 27-month-old male F344 rats. Serum LH levels declined significantly between 11 and 18 months and were still lower at 27 months of age, while testosterone levels declined continuously between 4 and 27 months. Hypothalamic NE and dopamine (DA) content also declined significantly with age, while serotonin and 5-hydroxy-indoleacetic acid content increased with age. Despite the decline in serum LH levels with age, in vitro basal LHRH release increased gradually with age as did NE-stimulated LHRH release. These data suggest that the age-related reduction in LH secretion by the male rat is due to a reduction in hypothalamic NE metabolism and not to an inability of the LHRH neuron to respond to NE stimulation.

Aging↗

Effect of dietary T-2 toxin on biogenic monoamines in discrete areas of the rat brain.

Acute T-2 toxin treatments alter biogenic monoamine concentrations in the brain; however, these perturbations have not been well documented or demonstrated in feeding trials. In this study, the effect of dietary T-2 toxin on regional brain concentrations of biogenic monoamines and their metabolites was investigated in male rats fed a semi-synthetic diet containing 0, 2.5 or 10 ppm T-2 toxin for either 7 or 14 days. Reduction in feed consumption, feed efficiency and weight gain was observed in rats fed either 2.5 or 10 ppm T-2 toxin. This effect was transient in animals fed the 10 ppm T-2 toxin diet, with feed consumption, feed efficiency and weight gain improving significantly during wk 2. T-2 toxin affected brain biogenic monoamine concentrations. In the nucleus raphe magnus, serotonin, 5-hydroxy-3-indoleacetic acid and norepinephrine increased in a dose-dependent manner, and dopamine increased transiently. In the substantia nigra of rats fed 10 ppm T-2, epinephrine increased after 7 days and norepinephrine decreased after 14 days, when compared with controls. Dihydroxyphenylacetic acid concentrations in the paraventricular nucleus and medial forebrain bundle were lower in T-2 toxin-treated rats than in control animals. The observed effects of T-2 toxin on brain monoamines and the resulting neurochemical imbalance may account for the physiological manifestation of trichothecene intoxication.

Administration, Oral↗

Fast axonal transport in rat sciatic nerve. Inhibition by pineal indoles.

The effect of pineal indoles on fast axoplasmic transport of proteins in the sciatic nerve was examined in rats injected with [3H]leucine in the sixth lumbar dorsal root ganglion. Melatonin (350-1100 nmol) applied locally in the sciatic nerve impaired significantly axonal transport. At a 350-nmol dose all other indoles tested (i.e., 5-hydroxyindoleacetic acid, 5-methoxyindoleacetic acid, serotonin, N-acetylserotonin, tryptamine, 5-methoxytryptamine) were less potent than melatonin to impair fast axonal flow. Vinblastine injected either into the ganglion or in the sciatic nerve markedly inhibited axonal transport.

5-Methoxytryptamine↗

Serotonergic involvement in the cardiovascular stimulation by thyrotropin-releasing hormone (TRH) in anesthetized rats.

The cardiovascular effects of intracerebroventricularly administered thyrotropin-releasing hormone (TRH) were studied in anesthetized rats in the presence of serotonin (5-HT) depletion induced by pretreatments with p-chloroamphetamine (PCA) or p-chlorophenylalanine (PCPA). After PCA the reduction of the whole brain 5-HT and 5-HIAA (5-hydroxy-indoleacetic acid) was 53% and 32% of control, respectively. PCPA reduced the brain 5-HT and 5-HIAA levels even to a greater extent, corresponding levels were 9% and 17% of control. TRH 1-100 nmol/kg increased dose dependently blood pressure and heart rate. PCPA pretreatment significantly attenuated the pressor effect and the tachycardia induced by TRH, whereas PCA did not modify the effects of TRH, which may be related to its weaker capacity to deplete 5-HT in TRH sensitive brain areas. These results suggest the involvement of the central serotonergic system in the TRH-induced cardiovascular stimulation.

Animals↗

Naltrexone administration during the preweanling period affects striatal and hypothalamic serotonergic systems, but not midbrain serotonergic or striatal dopaminergic systems in the adult rat.

We have recently reported that daily administration from birth of the opioid antagonist naltrexone (1 mg/kg, s.c.) affected dopaminergic and serotonergic systems in the striatum, hypothalamus and midbrain in rats of 7, 14 and 22 days of age. Previously, we have also reported that the same dose of naltrexone administered from birth until day 21 caused diverse behavioural alterations in adulthood. In the present work, using the same naltrexone administration schedule, we demonstrate that the intermittent blockade of opioid receptors during preweanling period induces significant decreases in striatal 5-hydroxytryptamine (5-HT) and 5-hydroxy-3-indoleacetic acid (5-HIAA) concentrations, and a significant reduction of hypothalamic 5-HT levels in the adult rat. However, no effects were found on midbrain serotonergic or striatal dopaminergic systems. These results are discussed in terms of possible different sensitivities of the diverse monoaminergic systems to the naltrexone treatment. Possible correlations with the behavioural data reported previously are also suggested.

3,4-Dihydroxyphenylacetic Acid↗

Changes in the serotonergic system during the sleep-wake cycle: simultaneous polygraphic and voltammetric recordings in hypothalamus using a telemetry system.

Changes in the serotonergic system in the posterior hypothalamus of freely moving rats were related to sleep and wakefulness using in vivo voltammetry (with carbon fiber microelectrodes) and polygraphic recordings. By using an optoelectronic telemetry system for the voltammetric signals, electrical cross-talk between the two settings was avoided and simultaneous neurochemical and electro-physiological recordings could be made so that a detailed time course of events could be obtained. Extracellular levels of the serotonin metabolite, 5-hydroxy-indoleacetic acid, measured every 2 min, increased with wakefulness and decreased with sleep: levels were significantly lower during desynchronized sleep than slow wave sleep. In vivo voltammetry associated with the optoelectronic telemetry system appears to be a useful tool for studying the relationship between neurochemical changes and electrophysiological events.

Animals↗

Human tryptamine metabolism decreases during night sleep.

Fourteen healthy male volunteers took part in a study which aimed to determine whether utilization of tryptamine changes in relation to sleep and wakefulness. For this purpose urine samples were collected every 4 hr and urinary tryptamine and indoleacetic acid (IAA) were determined by fluorometric and spectrophotometric methods. Urinary concentration of IAA progressively increased during the day and fell during the night when subjects were asleep but not when subjects were awake. This evidence indicates that behavioral state rather than circadian variation determines the level of urinary IAA. Tryptamine (T) concentration also progressively increased during the day and continued to increase during the night. The mean log10 (IAA/T) ratio indicates that tryptamine metabolism decreases during the night when subjects are asleep. Therefore, human sleep may be associated with diminished activity of peripheral tryptamine.

Adult↗

Changed central and peripheral catecholamines and indoleamines in one-way crossed-intestine rats: relationship to changes in feeding behavior and metabolism.

The involvement of central and peripheral catecholamines and serotonin (5-HT) in regulation of feeding and energy metabolism was examined in one-way crossed intestine rats that show large and sustained changes in daily food intake. Five to six weeks after the crossed-intestinal surgery, catecholamines and indoleamines in dissected major brain regions and in the heart, intrascapular brown adipose tissue (IntBAT), pancreas, and serum were determined using HPLC with electrochemical detection. The food-losing rats increased daily food intake from 70.8 to 126.3 g, whereas their partners decreased daily food intake from 67.1 to 38.7 g (p < .001). Compared with the partners and sham-operated controls, the food-gaining rats had increased 5-hydroxy-indoleacetic acid (5-HIAA) throughout the brain [hypothalamus, 442.9 vs. 383.5 (p < .05) and 404.2 ng/g (p < .05), Lateral cortex plus amygdala (LC + A), 236.6 vs. 216.8 (p < .05) and 212.0 ng/g (p < .05), brain stem, 282.9 vs. 238.7 (p < .05) and 245.1 ng/g (p = .05), cerebellum, 56.7 vs. 49.6 (p < .05) and 44.4 ng/g (p < .05)]. Higher 5-HIAA in food-gaining rats that were undereating are consistent with serotonin's role in inhibiting food intake. Peripherally, the rats gaining food showed significantly lower NE, 5-HT, and 5-HIAA in IntBAT compared with their partners (NE, 994.2 vs. 1236 ng/g, 5-HT 338.0 vs. 527 ng/g, and 5-HIAA, 39 vs. 51 ng/g). Because NE and 5-HT have been shown to exert stimulating effects on BAT-mediated thermogenesis, lower levels of NE, 5-HT, and 5-HIAA in IntBAT of food gaining rats are compatible with the lower metabolic rate observed in these animals. The results show that both central and peripheral catecholamines and serotonin are involved in regulation of food intake and energy metabolism.

Analysis of Variance↗

Cloning vectors, derived from a naturally occurring plasmid of Pseudomonas savastanoi, specifically tailored for genetic manipulations in Pseudomonas.

A minimal replicon of 1.8 kb isolated from a 10-kb plasmid of Pseudomonas savastanoi, pPS10, has been used to obtain a collection of small vectors specific for Pseudomonas (P. savastanoi, P. aeruginosa and P.putida). In addition, shuttle vectors that can be established both in Pseudomonas and Escherichia coli have been constructed by adding a pMB9 replicon. The vectors permit cloning of DNA fragments generated by a variety of restriction enzymes using different antibiotic resistance markers for selection and offer the possibility to screen recombinants by insertional inactivation. This cloning system can be used to establish recombinant plasmids in Pseudomonas either at low or high copy number. pPS10 derivatives are compatible with other Pseudomonas vectors derived from broad-host-range replicons of the incompatibility groups P1, P4/Q and W. Introduction and expression of the iaaMH operon in a P. savastanoi mutant deficient in the production of indoleacetic acid has been achieved using one of these vectors.

Cloning, Molecular↗

Comparison of the trichothecenes deoxynivalenol and T-2 toxin for their effects on brain biogenic monoamines in the rat.

Male Sprague-Dawley rats (180 g) were orally dosed with deoxynivalenol (DON) and T-2 toxin at 2.5 mg kg-1 body weight. Brains were collected 24 h postdosing, dissected into five brain regions and analyzed for biogenic monoamines by high performance liquid chromatography with electrochemical detection. DON and T-2 toxin treatment resulted in significantly elevated concentrations of the indoleamines, serotonin (HT) and 5-hydroxy-3-indoleacetic acid (HIAA) in all brain regions examined, whereas norepinephrine (NE) and dopamine (DA) regional concentrations were not significantly altered. These results indicate that DON and T-2 toxin influence brain biogenic monamine metabolism, and suggest that the central nervous system (CNS) actions of these trichothecenes are similar.

Animals↗

Rapid measurement of the monoamine content in small volumes of rat plasma.

A method for the simultaneous measurement of serotonin, catecholamines, and their metabolites, 5-hydroxy-indoleacetic acid, homovanillic acid, and 3, 4-dihydroxyphenylacetic acid, by ultrafiltration and microbore high-performance liquid chromatography with dual electrochemical detection in small plasma volumes was established. Unlike the traditional assays which require at least 1-2 ml of plasma for each measurement, the present method uses only a 20-microliters sample volume. Since blood loss is minimal, repeated blood sampling from a single animal as a rat becomes practicable. The present microassay provides low detection limits (signal-to-noise ratio = 3) for all analytes (0.2-0.5 pg per 5-microliters injection or 50-120 pg/ml plasma). Isocratic separation of these analytes on a microbore column is achieved within 15 min. This rapid and sensitive method can be used as a routine research tool in various physiological or pharmacokinetic studies especially in small animals.

Animals↗

Outcome of cardiac surgery for carcinoid heart disease.

OBJECTIVES: The hypothesis was that cardiac surgery for symptomatic carcinoid heart disease in conjunction with adjunctive therapy could improve the long-term outlook of patients with carcinoid heart disease. BACKGROUND: Patients with carcinoid heart disease have a dismal prognosis; most die of progressive right heart failure within 1 year after onset of symptoms. Improved therapies for the systemic manifestations of the carcinoid syndrome have resulted in symptomatic improvement and prolonged survival in patients without heart disease. METHODS: Twenty-six patients with symptomatic carcinoid heart disease underwent valvular surgery. Preoperative clinical, laboratory, Doppler echocardiographic and hemodynamic factors were evaluated. The survival of the surgical group was compared with that of a control group of 40 medically treated patients. RESULTS: There were nine perioperative deaths (35%), primarily from postoperative bleeding and right ventricular failure. Of the 17 surgical survivors, 8 were alive at a mean of 28 months of follow-up. The postoperative functional class of the eight surviving patients was substantially improved. Late deaths were primarily due to hepatic dysfunction caused by metastatic disease. The only predictor of operative mortality (p = 0.03) was low voltage on preoperative electrocardiography (limb lead voltage < or = 5 mm). Predictors of late survival included a lower preoperative somatostatin requirement and a lower preoperative urinary 5-hydroxy-indoleacetic acid level. There was a trend toward increased survival for the surgical group compared with the control group. CONCLUSIONS: Because new therapies have improved survival in patients with the malignant carcinoid syndrome, cardiac involvement has become a major cause of morbidity and mortality. Valve surgery is the only definitive treatment. Although cardiac surgery carries a high perioperative mortality, marked symptomatic improvement occurs in survivors. Surgical intervention should therefore be considered when cardiac symptoms become severe.

Actuarial Analysis↗

Assay of human blood aldehyde dehydrogenase activity by high-performance liquid chromatography.

A simple and sensitive method for routine analysis of aldehyde dehydrogenase (ALDH, EC 1.2.1.3) activity in human blood has been developed. The assays were performed by incubating diluted whole blood samples in sodium pyrophosphate buffer in the presence of NAD. The aldehyde derived from dopamine, or alternatively the aldehyde from serotonin, was used as the substrate and the acid formed was measured using high-performance liquid chromatography with electrochemical detection. The present method can be performed with a small sample (10-25 microliters) of whole blood and no time-consuming pretreatments of the samples are needed. Six to seven samples can be assayed per hour, and the precision of the method was 2%. For comparison, assays were also performed with two fluorimetric methods, one measuring the formation of indole-3-acetic acid from indole-3-acetaldehyde and the other measuring the rate of acetaldehyde disappearance.

3,4-Dihydroxyphenylacetic Acid↗