5-HIAA Concentrations Research Articles

Chemical Composition of Essential Oil from Flower of 'Shanzhizi' (Gardenia jasminoides Ellis) and Involvement of Serotonergic System in Its Anxiolytic Effect.

Gardenia jasminoides Ellis is a famous fragrant flower in China. Previous pharmacological research mainly focuses on its fruit. In this study, the essential oil of the flower of ‘Shanzhizi’, which was a major variety for traditional Chinese medicine use, was extracted by hydro distillation and analyzed by GC-MS. Mouse anxiety models included open field, elevated plus maze (EPM), and light and dark box (LDB), which were used to evaluate its anxiolytic effect via inhalation. The involvement of monoamine system was studied by pretreatment with neurotransmitter receptor antagonists WAY100635, flumazenil and sulpiride. The monoamine neurotransmitters contents in the prefrontal cortex (PFC) and hippocampus after aroma inhalation were also analyzed. The results showed that inhalation of G. jasminoides essential oil could significantly elevated the time and entries into open arms in EPM tests and the time explored in the light chamber in LDB tests with no sedative effect. WAY100635 and sulpiride, but not flumazenil, blocked its anxiolytic effect. Inhalation of G. jasminoides essential oil significantly down-regulated the 5-HIAA/5-HT in the PFC and reduced the 5-HIAA content in hippocampus compared to the control treatment. In conclusion, inhalation of gardenia essential oil showed an anxiolytic effect in mice. Monoamine, especially the serotonergic system, was involved in its anxiolytic effect.

The effects of cycloprolylglycine and its analogues on brain monoaminergic systems in BALB/c mice

Effects of chronic cycloprolylglycine (CPG) and its analogues GZK-001 and GZK-002 treatment at the doses 1 and 2 mg/kg on levels of monoamines and their metabolites in BALB/c mice brain were determined by HPLC. Neurochemical data demonstrated that antidepressant-like effects of the peptides are mediated by an increase in NA and decrease in DA content in frontal cortex. Alterations in striatal monoamine metabolism were observed predominantly after CPG's analogues treatment: the concentration of DA was increased, although its rate of turnover was diminished. In hippocampus more active was CPG: the levels of NE, DA, 5-HT, and its metabolite 5-HIAA were decreased. GZK-001 (1 mg/kg) caused a decrease in the concentration of DA and 5-HIAA. The present results suggest that antidepressant-like effects of CPG and its analogues are associated with DA, NE, and 5-HT systems.

Ethanol exposure during the brain growth spurt affects social behavior and increases susceptibility to acute ethanol effects during adolescence in male mice.

The brain is particularly vulnerable to ethanol effects during its growth spurt. Outcomes of early ethanol exposure such as hyperactivity have been extensively investigated; however, persons with fetal alcohol spectrum disorder frequently have social impairments and are heavy drinkers. Despite that, scant information is available regarding the neurobiological basis of these latter behavioral issues. Here, Swiss mice exposed to ethanol (Etoh, 5g/kg i.p., alternate days) or saline during the brain growth spurt [postnatal day (PN) 2 to 8] were used to assess social behavior after an ethanol challenging during adolescence. At PN39, animals were administered with a single ethanol dose (1g/Kg) or water by gavage and were then evaluated in the three-chamber sociability test. We also evaluated corticosterone serum levels and the frontal cerebral cortex serotoninergic system. Etoh males showed reductions in sociability. Ethanol challenging reverted these alterations in social behavior, reduced corticosterone levels, and increased the 5-HT2 receptor binding of male Etoh mice. No alterations were observed in 5-HT and 5-HIAA contents. These data support the idea that ethanol exposure during the brain growth spurt impacts social abilities during adolescence, alters ethanol reexposure effects, and suggests that stress response and serotoninergic system play roles in this phenomenon.

Factors Predicting 6-Month Smoking Cessation in Korean Adults.

The purpose of this study was to identify factors predicting 6-month smoking cessation in Korean adult smokers. This descriptive correlation study assessed levels of urine cotinine, serum cotinine, serum serotonin, and 5-hydroxyindoleacetic acid; tobacco withdrawal symptoms; and resilience among 164 Korean adult smokers. Serum cotinine levels were negatively related to resilience at six months (r = -.42, p = .019), but were positively related to the amount of smoking (r = .32, p = .008) and with the Week 6 tobacco withdrawal symptoms score (r = .48, p = .001, n = 41). Higher resilience was associated with a higher 5-HIAA concentration. Greater therapy attendance, resilience, and withdrawal symptoms explained 35.3% of the variance in 6-month smoking cessation (Nagelkerke R2 = .35, p < .001, n = 76). Efforts to increase counseling attendance rates and resilience and decrease withdrawal symptoms could be useful ways to improve smoking cessation rates.

NEUROCHEMICAL AND HISTOLOGICAL BRAIN ALTERATIONS AFTER TRAMADOL ADMINISTRATION TO ROTENONE- INDUCED PARKINSON'S DISEASE IN RATS

Objective: Tramadol is favorably used for relief of moderate and severe pain. Over 30% of Parkinson’s disease (PD) patients experience persistent pain that has a negative impact on their quality of life. However, its physiological effect in such disorder has not been studied. The current study aimed at investigating the neurochemical and histopathological changes resulting from tramadol administration to experimental PD- induced by rotenone in rats. Methodology: Forty adult male Sprague-Dawley rats were allocated into 5 equal groups; Group 1(control) received saline p.o and DMSO, s.c., Group 2(Rotenone) received rotenone (1.5 mg/kg, s.c., every other day for 12 days), Group 3 (Tramadol) received tramadol HCl given p.o., daily at doses of 20 mg/kg, Group 4 (Rot-Trama 10) PD-induced with rotenone and treated with tramadol HCl, 10 mg/kg, p.o., daily, Group 5(Rot-Trama 20) PD-induced with rotenone and treated with tramadol HCl, 20 mg/kg, p.o., daily. Results : PD-induced rats exhibited significantly reduced dopamine (DA) content (- 33.0%), increased serotonin ( 5-HT) content (+ 11.5%), but no change in 5-hydroxyindole acetic acid (5-HIAA) compared to vehicle-treated counterparts. Rotenone also inhibited both brain paraoxonase 1 (PON1) and acetylcholinesterase (AChE) activities and increased brain oxidative stress causing reduced glutathione depletion by 32% and increasing thiobarbituric acid reactive substances (TBARS), nitric oxide (NO) by 43% and 81%, respectively. Rotenone caused the appearance of apoptotic neurons with cytoplasmic vacoulations. On the other hand, tramadol -treated control rats showed increased DA (74%), 5-HT (23%), 5-HIAA (50%) contents and decreased serotonin turnover (18.0%) without causing oxidative stress. In rotenone-intoxicated rats, tramadol (10 or 20 mg/kg) increased brain dopamine and at 20 mg/kg increased 5-HT and 5-HIAA. The drug increased PON-1 activity, restored AChE activity and alleviated the changes in lipid peroxidation and reduced glutathione, increased tumour necrosis factor-alpha (TNF-α) without changing the histopathological changes caused by rotenone. Conclusion: These results indicate that short-term use of tramadol in an experimentally-induced PD has dual effects that should be carefully weighed. Tramadol decreased oxidative stress and restored normal DA content and AChE activity that can help in PD. However, the drug resulted in increased proinflammatory cytokine TNF-α and 5-HT level.

Analysis of 5-hydroxytryptamine and its related indoles in cerebrospinal fluid of leukemic children by gas chromatography-mass spectrometry

Abstract Background It is meaningful to quantify some neurotransmitters in cerebrospinal fluid (CSF) for pathology and clinical diagnosis. The objective of this study was to develop a rapid and reliable method for detecting 5-hydroxyindole ethanol (5-HTOL), 5-hydroxyindole acetic acid (5-HIAA), 5-hydroxytryptophan (5-HTP) and 5-hydroxytryptamine (5-HT) in CSF by gas chromatography-mass spectrometry (GC-MS), and explore the clinical significance of the levels of these neurotransmitters in CSF from acute lymphoblastic leukemia (ALL). Methods The levels of 5-HTOL, 5-HIAA, 5-HTP and 5-HT in CSF from children with ALL and a control (CON) group were examined by the proposed GC-MS method. Results The GC-MS method showed good sensitivity and accuracy. 5-HT and 5-HIAA contents in the ALL group were significantly lower than those in the CON group (p &lt; 0.01), while there was no significant difference in 5-HTP and 5-HTOL contents between the two groups (p &gt; 0.05). Conclusions This sensitive and reliable method could be used in studies focusing on clinical pathogenesis of ALL.

Determination of 5-Hydroxyindole-3-Acetic Acid in Wastewater by High Performance Liquid Chromatography Coupled with Tandem Mass Spectrometric Detection

Analysis of biomarkers in wastewater is increasingly seen as an important tool for valuation of health, nutrition and use of various substances by humans. Some biomarkers are used for population estimates, since the actual values of population size in cities can differ significantly from official counts, which inevitably leads to errors in assessing the impact of various factors to people calculated per capita. 5-hydroxyindole-3-acetic acid (5-HIAA) is the main metabolite of serotonin, which is excreted by urine and can be used as a biomarker for population estimates. The determination of this metabolite is more preferred than the detection of serotonin itself in terms of correctness of the results. A technique of extraction and subsequent quantitative determination of 5-HIAA in wastewater by high-performance liquid chromatography in combination with tandem mass spectrometric detection was developed. Poroshell Hilic column was used as a stationary phase which has an alternative selectivity compared to traditional C18 columns. Developed procedure is characterized by low detection limits (0.2 μg/L) and good selectivity. The conditions for liquid–liquid extraction of 5-HIAA from wastewater were selected. This technique provides reliable estimation of the concentration of 5-HIAA in wastewater.

Contrasting neurochemical and behavioral profiles reflects stress coping styles but not stress responsiveness in farmed gilthead seabream (Sparus aurata)

In fish, as well as in other vertebrates, contrasting suites of physiological and behavioral traits, or coping styles, are often shown in response to stressors. However, the magnitude of the response (i.e. stress responsiveness) has been suggested to be independent of stress coping style. One central neurotransmitter that has been associated with both stress responsiveness and differences in stress coping styles is serotonin (5-hydroxytryptamine, 5-HT).In this study, we investigated to what extent stress responsiveness reflects differences in stress coping, and the potential involvement of the 5-HT system in mediating such differences in farmed Gilthead seabream. Initially, fish were classified as proactive or reactive based on their behavioural response to net restraint. Following 1.5 months, fish classified as proactive still showed a higher number of escape attempts and spent longer time escaping than those classified as reactive. These differences were reflected in a generally higher brain stem 5-HT concentration and a lower telencephalic 5-HT activity, i.e. the ratio of 5-hydroxyindoleacetic acid (5-HIAA) to 5-HT, in proactive fish. Independent of stress coping styles, stress responsiveness was reflected in elevated 5-HIAA concentrations and 5-HIAA/5-HT ratios in telencephalon and brain stem together with increased plasma cortisol concentrations at 0.5 and 2 h following the last net restraint. The current results show that 5-HT signaling can reflect different behavioural output to a challenge which are independent of neuroendocrine responses to stress and lend support to the hypothesis that stress coping styles can be independent of stress responsiveness.

Use of selective serotonin reuptake inhibitors is associated with very low plasma-free serotonin concentrations in humans.

Background Selective serotonin reuptake inhibitors (SSRIs) block the serotonin transporter on neurons, but also on platelets, thus decreasing platelet serotonin concentrations in users of SSRIs. Data on plasma-free serotonin concentrations in SSRI users are lacking, while plasma-free serotonin is available for receptor binding and plays a role in several pathophysiological processes. We therefore measured the plasma-free and platelet serotonin concentrations in users of SSRIs and age-matched healthy controls, and we analysed plasma concentrations of the serotonin precursor tryptophan and serotonin metabolite 5-hydroxyindoleamineacetic acid (5-HIAA). Methods For this cross-sectional single-centre case control study, participants were recruited at the departments of Psychiatry and General Medicine. High-performance liquid chromatography combined with tandem mass spectrometry (LC-MS/MS) was used to measure plasma-free and platelet serotonin, plasma tryptophan and 5-HIAA concentrations. Preanalytical conditions were optimized by careful blood collection, rapid sample handling, high-speed centrifugation, drug and diet restrictions and age-matched controls. Results In 64 SSRI users, median concentrations of plasma-free and platelet serotonin were 10-fold and 14-fold lower, respectively, than in 64 matched controls. Patients using higher dose SSRIs or those with higher affinity for the serotonin transporter had lower plasma-free and platelet serotonin concentrations. Compared with controls, SSRI users had similar median plasma tryptophan concentrations but slightly higher plasma 5-HIAA concentrations. Conclusion SSRI users have low platelet serotonin and low plasma-free serotonin. This could not be explained by lower concentrations of its precursor tryptophan, and only partially by increased breakdown to 5-HIAA.

Electroacupuncture improves insomnia by down-regulating peripheral benzodiazepine receptor expression in hippocampus, and up-regulating 5-HT, 5-HIAA, TNF-α and IL-1β contents in hypothalamus in insomnia rats

To observe the therapeutic effect of electroacupuncture (EA) at five Back-Shu points on sleep, hippocampal peripheral benzodiazepine receptor (PBR) expression and hypothalamic 5-hydroxytryptamine (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), tumor necrosis factor alpha (TNF-α) and interleukin (IL)-1β contents in insomnia rats, so as to explore its mechanisms underlying improvement of insomnia. Forty male SD rats were randomly divided into control, model, EA and medication (Diazepam) groups (n=10 rats in each group). The insomnia model was established by intraperitoneal injection (i.p.) of para-Chlorophenylalanine (PCPA, 300 mg/kg) once daily for 2 days. EA (60 Hz, 1 mA) was applied to bilateral five Back-Shu points, i.e., Feishu (BL13), Xinshu (BL15), Ganshu (BL18), Pishu (BL20) and Shenshu (BL23) for 10 min, once daily for 6 days. Rats of the medication group were treated by gavage of Diazepam (0.92 mg/kg) once daily for 6 days. The sleep duration was recorded after i.p. of Pentobarbital Sodium (45 mg/kg). Histopathological changes of the hippocampus were displayed by H.E. staining. The contents of 5-HT, 5-HIAA, TNF-α and IL-1β in the hypothalamus were assessed by using ELISA. The expression levels of PBR mRNA and protein in the hippocampus were detected by quantitative real-time PCR, immunohistochemistry and Western blot, separately. Following modeling, the sleep duration was considerably shortened in rats of the model group relevant to the control group (P<0.05). After the treatment, the sleep duration was significantly increased in both EA and medication groups relevant to the model group (P<0.05). After modeling, the hippocampal neurons were obviously decreased in number, and disordered in the arrangement, the levels of hypothalamic 5-HT, 5-HIAA, TNF-α, and IL-1β were significantly down-regulated (P<0.05), and the expression of PBR mRNA and protein in hippocampus was obviously increased relevant to the control group (P<0.05). Following the treatment, the hippocampal neurons were increased in number and arranged regularly, and the contents of hypothalamic 5-HT, 5-HIAA, TNF-α, and IL-1β were considerably increased (P<0.05), and the expression of PBR mRNA and protein in hippocampus was significantly decreased in both EA and medication groups relevant to the model group (P<0.05). The therapeutic effect of EA was comparable to that of medication in increasing sleep duration, body weight, 5-HT and 5-HIAA contents (P>0.05), and significantly superior to that of the medication in increasing TNF-α and IL-1β levels (P<0.05), and considerably superior to that of medication in down-regulating PBR mRNA and protein expression (P<0.05). EA at five Back-Shu-points of the five Zang-organs can significantly improve the sleep in insomnia rats, which is closely associated with its effects in reducing the expression of PBR in hippocampus and up-regulating the levels of 5-HT, 5-HIAA, TNF-α and IL-1β in hypothalamus.

Decreased serotonin synthesis is involved in seizure-induced respiratory arrest in DBA/1 mice.

A known cause of seizure-induced respiratory arrest is the deficiency in serotonergic neurotransmission. Tryptophan hydroxylase-2 (TPH2) is the rate-limiting enzyme of central serotonin (5-hydroxytryptamine) synthesis which converts l-tryptophan to 5-hydroxytryptophan. A recent study revealed a reduction in TPH2 protein expression in the brainstems of DBA/1 mice that developed recurrent seizure-induced respiratory arrest, whereas the activity of this protein was unexplored. Thus this study aims to investigate the association between intrinsic 5-hydroxytryptamine synthesis in the brainstem and the susceptibility for sudden unexpected death in epilepsy in DBA/1 mice. The effect of LY393558, a potent 5-hydroxytryptamine reuptake inhibitor with 5-HT1B/1D receptor antagonist properties, on seizure-induced respiratory arrest evoked by acoustic stimulation was also examined in DBA/1 mice. ELISA results showed significantly decreased TPH2 activity in the brainstems of untreated DBA/1 mice than that of C57BL/6J mice. Moreover, the concentrations of 5-hydroxytryptamine, 5-hydroxytryptophan and 5-HIAA in the brainstems of DBA/1 mice with or without acoustic stimulation were significantly lower than that of C57BL/6J mice. Acute administration of LY393558 also significantly reduced seizure-induced respiratory arrest in DBA/1 mice. These observations provide novel evidences for the hypothesis that 5-hydroxytryptamine deficiency might be a potential cause of seizure-induced respiratory arrest.

Effect of Ziyin-Jianghuo formula on the neuroendocrine system of menopausal caused by Yin deficiency generating intrinsic heat type of rats

Objective To observe the effect of Ziyin-Jianghuo formula in treatment of Yin deficiency generating intrinsic heat type of the levels of monoamine neurotransmitters and estrogens in rats, and investigate its intervention in the neuroendocrine system. Methods There were 7 groups, which were sham operation group, model control group, estrogen tablet group, Gengnian capsule group, Ziyin-Jianghuo formula low, medium and high dose groups. Castration was performed by castration (extraction of ovaries) plus hot traditional Chinese medicine. The rats in the treatment group were given the above drugs 24 hours after the last administration of the hot Chinese medicine, once a day for 30 consecutive days. The sham operation group and the model control group were given an equal volume of purified water by simultaneous intragastric administration. The serum estradiol (E2), luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin (PRL) levels,uterine coefficient and monoamine neurotransmitters dopamine (DA), norepinephrine (NE), serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA) content in the hypothalamus were detected after 12 hours of the last treatment. Results Compared with the model group, the levels of serum FSH (4.39 ± 0.22 IU/L, 2.89 ± 0.91 IU/L, 2.84 ± 0.98 IU/L vs. 5.51 ± 0.24 IU/L), LH (14.48 ± 0.24 IU/L, 11.46 ± 0.33 IU/L, 5.28 ± 1.31 IU/L vs. 15.02 ± 0.37 IU/L) in the low, middle and high doses of Ziyin-Jianghuo formula significantly decreased (P<0.05), the levels of serum E2 (39.84 ± 6.08 pmol/L, 48.65 ± 6.77 pmol/L, 64.96 ± 7.97 pmol/L vs. 33.16 ± 4.62 pmol/L) significantly increased (P<0.05). The content of DA, 5-HT, 5-HIAA in the hypothalamus and the 5-HT/NE (0.48 ± 0.02, 0.43 ± 0.03, 0.27 ± 0.02 vs. 0.67 ± 0.02), 5-HIAA/5-HT (1.74 ± 0.09, 1.71 ± 0.10, 1.80 ± 0.17 vs. 2.00 ± 0.10) in the low, middle and high doses of Ziyin-Jianghuo formula significantly decreased (P<0.05), the content of NE (663.34 ± 9.81 ng/kg, 695.94 ± 10.54 ng/kg, 790.76 ± 16.35 ng/kg vs. 602.95 ± 13.24 ng/kg) in the hypothalamus in the low, middle and high doses of Ziyin-Jianghuo formula significantly increased (P<0.05). The levels of serum PRL (10.16 ± 1.26 μg/L, 7.22 ± 1.26 μg/L vs. 14.80 ± 1.64 μg/L) in the middle and high doses of Ziyin-Jianghuo formula significantly decreased (P<0.05). Conclusions The Ziyin-Jianghuo formula has a significant positive regulation effect on the neuroendocrine system of menopausal Yin deficiency generating intrinsic heat type of rats, and this process is dose-dependent and can improve a series of symptoms caused by autonomic dysfunction. Key words: Climacteric syndrome; Nourishing yin depressing fire; Yin deficiency generating intrinsic heat type; rats; Neuroendocrine function; Rats

Effect of Flavobacterium psychrophilum on the neuroendocrine response of rainbow trout (Oncorhynchus mykiss) in a time course experiment

The aim of this study was to examine the effects of Flavobacterium psychrophilum, a pathogen that is economically important in the aquaculture sector, on the neuroendocrine response of Oncorhynchus mykiss during a time course experiment with sampling at 0.5, 1, 2, 6, 10, and 30 days post injection (dpi). In the brain, serotonin (5HT) content increased in the infected group at all the measured time points, a similar pattern was observed for 5-hydroxyindole-3-acetic acid (5HIAA). Infected fish presented an increase in brain dopamine levels on day 0.5 and 1 dpi. A non-significant variation in noradrenaline levels was observed on all treatment days. Foregut 5-HT and 5-HIAA content in the infected group presented the highest 5-HT concentrations with 248.6 and 983.5 ng/g tissue at 0.5 dpi respectively. Midgut 5-HT and 5-HIAA levels presented the highest 5-HT concentrations, 486.9 ng/g tissue and 1006.4 ng/g tissue respectively, at the beginning of the experiment (0.5 dpi). 5-HT levels in the hindgut presented the highest concentrations with 233.9 ng/g tissue at 0.5 dpi, while 5-HIAA presented the highest concentrations, 690.5 ng/g tissue, at the same time point. After injection with F. psychrophilum the neuroendocrine response in rainbow trout was tissue dependent. Brain levels of 5HT and 5HIIA indicate that the neuroendocrine response increased together with dopamine following intramuscular infection. These increases are in line with reports from other authors, indicating an early response of catecholamines as neurotransmitters to stressful stimulus. In addition the intestinal response was also increased, implying that there could be a possible relationship between the serotonergic system at the intestinal level and the immune system.

Measurement of urinary 5-HIAA: correlation between spot versus 24-h urine collection.

BackgroundThe 24-h urinary output of 5-hydroxyindoleacetic acid (5-HIAA) is used to monitor disease progression and treatment responses of neuroendocrine neoplasms (NENs). Several conditions are required for 5-HIAA assay, involving urine collection/preservation and food/drug restrictions.AimTo evaluate the correlation between 5-HIAA concentration in a spot urine sample and the output in a 24-h urine collection, and whether spot urine specimens can replace 24-h collection.MethodsPatients with NENs or symptoms suggestive of NENs were asked to provide a separate spot urine at the end of the 24-h urine collection for 5-HIAA assessment. The upper reference limit for 24-h urinary 5-HIAA was 40 µmol/24 h. 5-HIAA measurements in spot urine samples were corrected for variation in urine flow rate by expressing results as a ratio to creatinine concentration.ResultsWe included 136 paired urinary samples for 5-HIAA assessment from 111 patients (100 NENs). The correlation between 5-HIAA values measured in 24-h and spot urines was r = +0.863 (P < 0.001) and r = +0.840 (P < 0.001) including only NEN patients. Using the 24-h urinary 5-HIAA as reference method, the AUC on ROC analysis for spot urinary 5-HIAA was 0.948 (95% CI, 0.914–0.983; P < 0.001), attaining a sensitivity of 83% and specificity of 95% using 5.3 mol/mmol as cut-off for the spot urine. The AUC among NEN patients alone was 0.945 (95% CI, 0.904–0.987; P < 0.001).ConclusionsThe ratio of 5-HIAA to creatinine in a spot urine could replace the measurement of 5-HIAA output in a 24-h urine collection, especially for follow-up of patients with known elevated 5-HIAA levels.

Urine 5-hydroxyindoleacetic acid in Cavalier King Charles spaniels with preclinical myxomatous mitral valve disease

Higher concentrations of circulating serotonin have been reported in Cavalier King Charles spaniels (CKCS) compared to other dog breeds. The CKCS is also a breed highly predisposed to myxomatous mitral valve disease (MMVD). The aim of this study was to determine urine concentrations of 5-hydroxyindoleacetic acid (5-HIAA), the major metabolite and excretion product of serotonin, in a population of CKCS with preclinical MMVD, and to evaluate whether urine 5-HIAA concentrations were associated with MMVD severity, dog characteristics, setting for urine sampling, platelet count, and serotonin concentration in serum and platelet-poor plasma (PPP). The study population consisted of 40 privately-owned CKCS (23 females; 17 males) with and without preclinical MMVD as follows: American College of Veterinary Internal Medicine (ACVIM) group A (n = 11), ACVIM group B1 (n = 21) and ACVIM group B2 (n = 8).Urine 5-HIAA concentrations were not significantly associated with preclinical MMVD disease, platelet count or circulating concentrations of serotonin (in serum and PPP; P > 0.05). Females had higher 5-HIAA concentrations than males in morning urine collected at home (females, 3.1 [2.9–3.7] μmol/mmol creatinine [median and quartiles]; males, 1.7 [1.2–2.2] μmol/mmol creatinine; P = 0.0002) and urine collected at the clinic (females, 3.5 [3.1–3.9] μmol/mmol creatinine; males, 1.6 [1.3–2.1] μmol/mmol creatinine; P < 0.0001). Five-HIAA concentrations in urine collected at home and at the clinic were significantly associated (P = 0.0004; r = 0.73), and higher concentrations were found in urine collected at the clinic (P = 0.013). Urine 5-HIAA concentration was influenced by sex and setting of urine sampling. Urine 5-HIAA concentration was not associated with MMVD severity or circulating concentrations of serotonin in CKCS with preclinical disease.

Citalopram and Tianeptine: Pharmacological Interventions in alcohol withdrawal-induced negative mood states and serotonin insufficiency in Albino Wistar male rats

ABSTRACT The present study aims to investigate the neurochemical and behavioural effects of tianeptine and citalopram to block alcohol withdrawal-induced audiogenic seizures in alcohol withdrawal (AW) rats. Citalopram and tianeptine were administered sub-chronically to block AW-induced audiogenic seizures. Brain regional tryptophan (TRP), 5-hydroxytryptamine (5-HT), 5-hydroxyindoleacetic acid (5-HIAA) concentrations were determined using high-performance liquid chromatography connected to the fluorimetric detector. Citalopram increased brain TRP concentration in all the regions, however, tianeptine increased brain TRP concentration only in amygdala and hippocampus. Increased brain serotonin concentration was seen by citalopram but not by tianeptine in all the regions. Further, tianeptine was shown to increase 5-HT turnover in all the regions, however, citalopram appeared to increase 5-HT turnover only in the hippocampus. It is concluded that the citalopram and tianeptine behave differently on the intrinsic pathway of serotonin metabolism that appeared to be compensated by the release pattern of serotonin. Further, chronic exposure of serotonergic agents causes restoration and structural reforming of serotonin reuptake mechanism that is desensitized following chronic alcohol exposure. Thus the inclusive approach of the serotonergic system plays an undoubted role in the pharmacological management of AW syndrome.

In vivo microdialysis and in vitro HPLC analysis of the impact of paeoniflorin on the monoamine levels and their metabolites in the rodent brain.

Background: Paeoniflorin (PF) possesses several effects such as analgesic, the anti-spasmodic effect on smooth muscle. It protects the cardiovascular system and reveals the neuroprotective effect on cerebral ischemia. Monoamine system has been identified to have complex regulatory effects in pain signaling. There are no reports regarding the impact of PF on monoamine levels in the rodent brain by microdialysis. In this study, the effects of PF on monoamines and their metabolites in the rodent brain using in vivo microdialysis and in vitro high performance liquid chromatography (HPLC) analysis.Methods: Male S.D. rats were anesthetized, fixed onto the stereotaxic instrument to identify the positions of corpus striatum and cerebral cortex. Drilled a hole in the skull of anesthetic rats and proceeded microdialysis, and gave PF (100 μg, i.c.v.). Collected the dialysate and the concentration of monoamines and their metabolites in dialysate and analyzed with HPLC-ECD. Male ICR mice were administered with PF (96 μg, i.c.v.) and with Ringer solution as a control. After 20 mins of administration, the mice were cut off the brain immediately and separated into eight regions according to the method of Glowinski. Added extraction solution to each region, homogenized and extracted for further procedure. The extract was centrifuged, sucked the transparent layer and centrifuged once more. The transparent layer was filtered with a 0.22 μm nylon filter and analyzed with HPLC-ECD (electrochemical detection).Results: PF increased the content of DOPAC and NE in the cortex, and increased the content of NE and decreased the content of 5-HT in the medulla of the homogenized mice brain tissue. By microdialysis, PF increased the content of DOPAC and 5-HIAA in anesthetic rat cortex and expanded the content of DOPAC, HVA, and 5-HIAA in anesthetic rat striatum.Conclusions: It reveals that PF could activate the release of monoamines and increase their metabolites in the rodent brain.

Rumen-Protected 5-Hydroxytryptophan Improves Sheep Melatonin Synthesis in the Pineal Gland and Intestinal Tract.

BackgroundBased on the extensive biological effects of melatonin (MLT), it is beneficial to increase the MLT content in the bodies of animals at a specific physiological stage. This study was conducted to investigate the effect of a diet supplemented with rumen-protected (RP) 5-hydroxytryptophan (5-HTP) on the pineal gland and intestinal tract MLT synthesis of sheep.Material/MethodsEighteen Kazakh sheep were assigned randomly to 3 diet groups: control group (CT, corn-soybean meal basal diet), CT+111 group (111 mg/kg BW RP 5-HTP), and CT+222 group (222 mg/kg BW RP 5-HTP). The gene expressions of aromatic amino acid decarboxylase (AADC), arylalkylamine N-acetyltransferase (AA-NAT), hydroxyindole-O-methyltransferase (HIOMT), monoamine oxidase A (MAOA), and the intermediates of MLT synthesis were observed from the pineal gland and intestinal tract by the reverse transcription (RT)-PCR method. The 5-HTP, 5-HT, N-acetylserotonin (NAS), MLT, and 5-hydroxyindole acetic acid (5-HIAA) contents in the pineal gland and intestinal tract were analyzed by ultra-high-performance liquid chromatography–tandem mass spectrometry.ResultsThe study showed that the pineal gland HIOMT expression (P<0.05), MLT (P<0.05) and 5-HIAA (P<0.05) levels in the 222 mg/kg group significantly increased compared to those in the CT and CT+111 mg/kg groups. In addition, the AADC (P<0.01) and AA-NAT (P<0.05) gene expression levels in the duodenum and jejunum were increased by the supplementation of RP 5-HTP.ConclusionsRumen-protected 5-hydroxytryptophan promoted melatonin synthesis in the pineal gland and intestinal tract during the natural light period.

The effects of fluoxetine on socioemotional behavior in female rhesus monkeys is influenced by social status

BackgroundChronic adverse social experience is a major environmental variable linked to multiple psychiatric disorders. The use of social subordination in nonhuman primates represents a translational model of chronic psychosocial stress. While social dominance is associated with a resistance to a range of stressors and social subordination produces stress‐susceptible phenotypes, the neural mechanisms that underlie status‐induced differences in susceptibility remain unclear. The current study assessed the effects of increasing serotonin (5HT) activity by administering fluoxetine on rates of socioemotional behavior (including agonistic, affiliative, and anxiety‐like behaviors) in female rhesus monkeys. We hypothesized that fluoxetine would increase rates of aggression in dominant but not subordinate animals.MethodsSubjects were gonadally intact adult female rhesus monkeys (n=14) housed in small social groups of four to six females each (6 dominant and 8 subordinate females). Using a counterbalanced design, subjects received both a 14‐day treatment with fluoxetine (SC dose of 2.8 mg/kg/day) and vehicle (50% polyethylene glycol in sterile saline) separated by a three‐week washout period. Behavioral observations were collected every two days using a standard monkey ethogram during each treatment, and CSF samples were collected at the end of each treatment for assessment of central 5‐hydroxyindoleacetic (5HIAA).ResultsThe amount of aggression directed at group mates was influenced by a status by treatment interaction (p=0.05, η2=0.27), with fluoxetine enhancing aggression in dominant females and decreasing aggression in subordinate females. As expected, subordinate females emitted significantly higher rates of submission behavior than did dominant females and this was unaffected by treatment (p=0.001). Affiliation emitted towards others was influenced by a status by treatment interaction (p=0.05, η2=0.27), as fluoxetine treatment decreased affiliation emitted in dominant females and increased it in subordinates. Anxiety‐like behavior was also influenced by a status by treatment interaction (p=0.011), as anxiety‐like behaviors were reduced only in subordinate females by fluoxetine treatment (p=0.012). CSF 5HIAA concentrations were reduced by fluoxetine (p&lt;0.001) regardless of social status.ConclusionThe data show that increased 5HT activity following fluoxetine treatment in female monkeys alters socioemotional behavior in a status‐dependent manner. Notably, subordinate females are less aggressive and more affiliative during fluoxetine treatment. Future studies include determining whether these effects of fluoxetine are sex dependent and whether subordinate males respond similarly to subordinate females.Support or Funding InformationThis research was supported by an NIMH grant MH110212.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Determination of thresholds values for platelet serotonin and urinary 5-HIAA concentrations for the biological diagnosis of digestive neuroendocrine tumors

Platelet serotonin and its urinary metabolite 5-HIAA (5-hydroxyindolacetic acid) are the main biomarkers measured for the detection of neuroendocrine tumors (NET). We observe in our laboratory many false positives or false negatives for the 2 assays using threshold values given by the manufacturer. We aim to determine our own local threshold values for a better detection of gastrointestinal NETs. We studied patients with measurement of platelet serotonin and/or urinary 5-HIAA in University Hospital of Tours between January 2005 and June 2016. We established an «index» cohort with 75% of patients to determine local threshold value for the 2 parameters. A "validation" cohort constituted with 25% of remaining patients allowed us to compare the performances of manufacturer's values with local threshold values. Two hundred ninety patients were included, with 19 suffering from NETs. Local threshold value for platelet serotonin was determined at 5.13 amol/platelet, the one for urinary 5-HIAA at 3.60 μmol/mmol urinary creatinine. Platelet serotonin specificity was better with local threshold value for identical sensibility (0.75). Urinary 5-HIAA sensibility was improved with local threshold value (1 vs 0.667) for identical specificity (0.902). Using our local threshold value for platelet serotonin and urinary 5-HIAA improved diagnostic performances of these biochemical markers to detect NETs.