Long-term scopolamine treatment altered locomotor, exploratory and anxiety-like behaviours of albino rats

Background Animal models are used to provide an adequate investigation of brain-behaviour, physiological and path physiological relationships to give insight into human behaviour and the underlying processes of drugs affecting the nervous system. Scopolamine; SCO (alkaloid l-(2)-scopolamine [l-(2)-hyoscine]) has a competitive inhibitory effect on muscarinic receptors for acetylcholine. Thus, this study was designated to investigate the effect of long-term SCO treatment on locomotor, exploratory and anxiety-like behaviours of rats using open field test. Results The long-term SCO treatment induced a prominent increase in locomotion (hyperactivity) and exploratory behaviour of rats. In addition, anxiety-like behavioural patterns showed a non-significant difference in SCO treated compared to control. Serotonin level was significantly decreased in the scopolamine treated group in comparison with the control group. Conclusions Data suggested that long-term SCO treatment resulted in marked neurobehavioural alterations in a rat as an animal model.

Interaction effect of serum serotonin level and age on the 12-week pharmacotherapeutic response in patients with depressive disorders

Despite the recognized antidepressant role of serotonin (5-hydroxytryptamine [5-HT]) signaling pathways in the central nervous system, the association between baseline peripheral 5-HT level and the antidepressant treatment response in clinical studies remains debatable. We investigated the interaction effects of baseline serum 5-HT level and age on the 12-week remission in outpatients with depressive disorders who received stepwise antidepressant treatment. Baseline serum serotonin levels were measured and the age of 1094 patients recorded. The patients received initial antidepressant monotherapy; then, patients with an insufficient response or who experienced uncomfortable side effects received alternative treatments every 3 weeks (3, 6, and 9 weeks). Subsequently, 12-week remission, defined as a Hamilton Depression Rating Scale (HAMD) score of ≤ 7, was evaluated. Individual and interaction effects of serum 5-HT level (as a binary [low vs. high, based on the median value of 72.6 ng/mL] or continuous variable) and age (as a binary [< 60 vs. ≥ 60 years] or continuous variable) on the 12-week remission rate were analyzed using logistic regression models after adjusting for relevant covariates. High 5-HT (≥ 72.6 ng/mL) and age ≥ 60 years were associated with the highest 12-week remission rates and a significant multiplicative interaction effect. The interaction effect of the two variables on the 12-week remission rate was significant even when analyzed as a continuous variable. Our study suggests that the association between baseline serum 5-HT level and 12-week antidepressant treatment outcomes differs according to patient age.

Correlation of Telomere Length and Serotonin Levels with Job Stress and Locus of Control Type among Nurses at a Private Hospital in Gianyar, Indonesia

Objectives. Telomere length and its relationship to job stress among workers in the health sector in Indonesia, especially in Bali, have never been studied. The purpose of the study was to analyze the correlation of the telomere length and serotonin levels to job stress and the type of locus of control (LOC) among nurses who were running shift work. Method. This analytical cross-sectional study was conducted from April to November 2018 among 68 nurses who were running shift work at a private hospital in Gianyar. The telomere length was measured with the absolute telomere length (aTL) using quantitative real-time polymerase chain reaction (qPCR) technique. Locus of control (LOC) was assessed using the IPC-LOC questionnaire. Serotonin level was measured by the immunoassay technique. Job stress was measured using the BJSQ. Data analysis was conducted with Chi-squared test, correlation test, and independent sample t-test. Results. There was a significant correlation of job stress with telomere length (p = 0.03). Nurses with job stress faced a 2.9 times risk of short telomere (prevalence ratio, PR = 2.95, 95% CI 1.02, 7.91). The mean telomere length was 17.32 ± 7.80 in nurses who experienced job stress vs. 22.45 ± 8.41 in nurses who did not experience job stress. Comparing with a previous study done by to O’Callaghan et al., in the young group, the mean aTL was 97.2 kb/diploid genome (range 35-260). We also found a significant correlation of job stress score with serotonin level (p = 0.02). The serotonin level among nurses with LOC-e type was lower than LOC-i. Conclusion. There was a significant correlation between job stress and telomere length, where nurses who experienced job stress had a shorter telomere than those who did not experience job stress. There was also a significant correlation between job stress and serotonin levels, where the mean of serotonin levels in nurses with LOC-e type was lower than LOC-i.

Effect of a high-fat diet and chromium on hormones level and Cr retention in rats

Aims The aim of the study was to determine how the administration of a high-fat diet supplemented with various forms of chromium to rats affects accumulation of this element in the tissues and levels of leptin, ghrelin, insulin, glucagon, serotonin, noradrenaline and histamine, as well as selected mineral elements. Methods The experiment was conducted on 56 male Wistar rats, which were divided into 8 experimental groups. The rats received standard diet or high fat diet (HFD) with addition of 0.3 mg/kg body weight of chromium(III) picolinate (Cr-Pic), chromium(III)-methioninate (Cr-Met), or chromium nanoparticles (Cr-NP). Results Chromium in organic forms was found to be better retained in the body of rats than Cr in nanoparticles form. However, Cr-Pic was the only form that increased the insulin level, which indicates its beneficial effect on carbohydrate metabolism. In blood plasma of rats fed a high-fat diet noted an increased level of serotonin and a reduced level of noradrenaline. The addition of Cr to the diet, irrespective of its form, also increased the serotonin level, which should be considered a beneficial effect. Rats fed a high-fat diet had an unfavourable reduction in the plasma concentrations of Ca, P, Mg and Zn. The reduction of P in the plasma induced by supplementation with Cr in the form of Cr-Pic or Cr-NP may exacerbate the adverse effect of a high-fat diet on the level of this element. Conclusion A high-fat diet was shown to negatively affect the level of hormones regulating carbohydrate metabolism (increasing leptin levels and decreasing levels of ghrelin and insulin).

Serotonin level in biological fluids as a marker of neuroorthopedic diseases diagnostics and treatment efficiency

This article discusses the issues of studying the dynamics of changes in serotonin in biological fluids as a marker in various neuro-orthopedic diseases in patients of different ages. For this, an analysis of clinical practice has been carried out. It is concluded that changes in serotonin levels can be considered as an indicator of pain sensations and control of ongoing therapy in neuro-orthopedic pathologies. The need for a further indepth study of the existing practice of assessing changes in the level of serotonin in biological fluids during conservative treatment and after surgery in various cases of neuro-orthopedic diseases in patients of different ages is indicated.

Serotonin regulates hepcidin expression via a gut-liver axis

Liver hepcidin, is well recognized as the central hormone of systemic iron regulation. Although serotonin is most recognized as a brain neurotransmitter, prodigious quantities are synthesized in gut enterochromaffin cells and several lines of evidence, also identified the gut as an essential sensor and regulator of iron homeostasis. Using a mouse model deficient for peripheral serotonin (Tph1 KO), we identified gut-derived serotonin as a key physiological factor in hepcidin regulation. Serotonin represses hepcidin's through a 5HT2B receptor-dependent pathway, independently of any other known hepcidin regulators, including bone marrow signals. This regulation is conserved in humans and shows physiological significance as a negative correlation between serotonin and hepcidin levels was observed in a cohort of healthy individuals. Moreover, in pathological situation such as acute heart failure, where iron deficiency has a negative prognostic impact, we provide evidence that an increase in serotonin level seems necessary to repress hepcidin level, to increase iron availability.

Serotonin variations and sleep disorders among shift workers. A cross-sectional study

Sleep disorders are prevalent occupational health problems among shift workers, especially healthcare workers with long shifts. Serotonin is a neurotransmitter related to circadian variations accompanied by shift work. A cross-sectional study was performed on 73 nurses at a tertiary hospital in Cairo, Egypt, to assess sleep quality among shift work nurses (SWNs), to determine blood serotonin level, and its relation to shift work and sleep quality. A demographic and occupational history questionnaire, Pittsburgh Sleep Quality Index (PSQI) questionnaire, and measurement of blood serotonin were carried out to the studied group. The data were analyzed using SPSS 25, and descriptive statistics, unpaired t-test, ANOVA, Kruskal–Wallis Test, Chi-square, Spearman correlation, and multivariate regression analysis were utilized. The results showed that the mean PSQI global score was significantly higher among SWNs than non-shift work nurses (NSWNs) and was the highest (10.32 ± 3.56 and 10.22 ± 2.4, respectively) among rotatory and fixed night shift nurses. Blood serotonin showed highly significant differences between SWNs over NSWNs ( p = 0.001), and mostly reduced among rotatory and fixed night shift nurses (66.7% and 65%, respectively). Moreover, there were highly significant differences in serotonin levels between poor and good sleep quality nurses ( p < 0.001), and most of the poor sleep quality nurses (62.7%) had low serotonin levels. Abnormal serotonin level (odds = 246.5) and working years (odds = 1.2) were statistically significant predictors of poor sleep quality. In conclusion, SWNs, especially rotating and night shift nurses, suffer from poor sleep quality associated with abnormal levels of blood serotonin.

Inflammation Disturbed the Tryptophan Catabolites in Hippocampus of Post-operative Fatigue Syndrome Rats via Indoleamine 2,3-Dioxygenas Enzyme and the Improvement Effect of Ginsenoside Rb1

AimPost-operative fatigue syndrome (POFS) is a common complication that prolongs the recovery to normal function and activity after surgery. The aim of the present study was to explore the mechanism of central fatigue in POFS and the anti-fatigue effect of ginsenoside Rb1.MethodWe investigated the association between inflammation, indoleamine 2,3-dioxygenase (IDO) enzyme, and tryptophan metabolism in the hippocampus of POFS rats. A POFS rat model was induced by major small intestinal resection. Rats with major small intestinal resection were administered ginsenoside Rb1 (15 mg/kg) once a day from 3 days before surgery to the day of sacrifice, or with saline as corresponding controls. Fatigue was assessed with the open field test (OFT) and sucrose preference test (SPT). ELISA, RT-PCR, Western blot, immunofluorescence, and high-performance liquid chromatography (HPLC) were used to test the inflammatory cytokines; p38MAPK, NF-κB/p65, and IDO enzyme expressions; and the concentrations of tryptophan, kynurenine, and serotonin, respectively.ResultOur results showed that POFS was associated with increased expressions of inflammatory cytokines and p38MAPK and higher concentrations of kynurenine and tryptophan on post-operative days 1 and 3; a lower serotonin level on post-operative day 1; and an enhanced translocation of NF-κB/p65 and the IDO enzyme on post-operative days 1, 3, and 5. Ginsenoside Rb1 had an improvement effect on these.ConclusionInflammatory cytokines induced by large abdominal surgery disturb tryptophan metabolism to cause POFS through the activation of the p38MAPK–NF-κB/p65–IDO pathway in the hippocampus. Ginsenoside Rb1 had an anti-fatigue effect on POFS by reducing inflammation and IDO enzyme.