Brain Content Of Serotonin Research Articles

Neuroprotective role of camphor against ciprofloxacin induced depression in rats: modulation of Nrf-2 and TLR4

Background Depression affects people feeling to be anxious, worried, and restless. They also lose interest in activities, concentrating and appetite, they finally may attempt suicide. Depression is the second chronic disease, as a source of the global burden of disease, after heart disease. Its prevalence elevated seven times during the COVID-19. Aim The current study was designed to evaluate camphor neuroprotective role against rats’ ciprofloxacin-induced depression. Materials and methods Depression was induced by administration of ciprofloxacin (50 mg/kg; orally) for 21 days. Wister albino male rats were divided into five groups. Group I (normal control): rats were given normal saline. Group II: rats received camphor (10 mg/kg; i.p.) for 21 days. Group III (depression control): rats received ciprofloxacin only. Groups IV and V: rats received camphor (5 and 10 mg/kg; i.p.) for 21 days concurrent with ciprofloxacin. Behavior tests as forced swimming test, activity cage, and rotarod were estimated. Oxidative stress and antioxidant biomarkers as malondialdehyde (MDA), nitric oxide (NO), catalase, and nuclear factor erythroid 2-related factor 2 (Nrf-2) besides inflammatory biomarkers as Toll-like receptor 4 (TLR4) and tumor necrosis factor alpha (TNF-α) as well as neurotransmitters were determined. Finally, histopathological examination was done. Results Camphor increased catalase and Nrf-2 activities, decreased NO, MDA, TNF-α, TLR4 serum levels, and elevating brain contents of serotonin, dopamine, gamma-amino butyric acid (GABA) and P190-RHO GTP protein with normal neuronal cells of the frontal cortex. Conclusion Camphor has neuroprotective effect via modulation of Nrf-2 and TLR4 against ciprofloxacin-induced depression in rats.

Protective effect of Hypericum perforatum on dexamethasone-induced diabetic depression in rats

Background/aim Complex interactions among psychological, social, and biological factors are the reason for diabetic depression. The present study was designed to evaluate the effect of Hypericum perforatum extract on dexamethasone-induced diabetic depression. Materials and methods A total of 24 adult male Wistar rats were divided into four groups (six rats each): group 1: control; group 2: daily treated with dexamethasone (0.44 mg/kg; intraperitoneally for 28 days); and groups 3 and 4: daily treated with H. perforatum extract (100 and 200 mg/kg; orally) concurrent with dexamethasone injection for 15 consecutive days. Plasma levels of blood glucose, glucose transporter-2, CD4, total antioxidant capacity, malondialdehyde, and nitric oxide were measured. In addition, the brain contents of serotonin, dopamine, cyclooxygenase-2, and transforming growth factor-β1 were determined. Moreover, assessment of histopathological changes of brain tissues and immunohistochemical analysis of caspase-9 were performed. Results Significant elevations were recorded in blood glucose level and plasma levels of malondialdehyde and nitric oxide. In addition, brain contents of dopamine, transforming growth factor-β1, and cyclooxygenase-2 were increased significantly in dexamethasone-treated group. However, plasma levels of glucose transporter-2, CD4, and total antioxidant capacity and the brain content of serotonin were significantly decreased in comparison with control group. Both doses of H. perforatum significantly ameliorated all biochemical parameters and alleviated histopathological and immunohistochemical apoptotic changes induced by dexamethasone in the rat cortex, striatum, and hippocampus. Conclusion H. perforatum extract possesses antioxidant, anti-inflammatory, and immunomodulatory effects against dexamethasone-induced diabetic depression.

Central Fatigue Induced by Losartan Involves Brain Serotonin and Dopamine Content

To investigate the influence of angiotensin II (Ang II) AT1 receptors blockade on central fatigue induced by brain content of serotonin (5-HT) and dopamine (DA) during exercise. Losartan (Los) was intracerebroventricularly injected in rats before running until fatigue (n = 6 per group). At fatigue, brains were quickly removed for measurement of 5-HT, 5-hydroxyindoleacetic acid (5-HIAA), DA, and 3,4-dihydroxyphenylacetic acid by high-pressure liquid chromatography in the preoptic area, hypothalamus, hippocampus, and frontal cortex. Intracerebroventricular injection of Los increased 5-HT content in the preoptic area and hypothalamus. Such results correlated positively with body heating rate and inversely with time to fatigue. On the other hand, time to fatigue was directly correlated with the diminished concentration of 5-HT in the hippocampus of Los rats. Although the levels of DA were not affected by Los treatment during exercise in any of the brain areas studied, a higher 5-HT/DA ratio was seen in the hypothalamus of Los animals. This higher hypothalamic 5-HT/DA ratio correlated positively with body heating rate and negatively with time to fatigue. Our results show that central fatigue due to hyperthermia and increased body heating rate induced by central Ang II AT1 receptor blockade in exercising rats is related with higher 5-HT content in the preoptic area and hypothalamus as well as with decreased levels of this neurotransmitter in the hippocampus. Furthermore, the interaction between 5-HT and DA within the hypothalamus seems to contribute to hyperthermia and premature central fatigue after angiotensinergic inhibition.

Dexamethasone reduces food intake, weight gain and the hypothalamic 5-HT concentration and increases plasma leptin in rats

This study was conducted to define the regulatory mechanisms underlying stress-induced decreases in food intake and weight gain. Rats received a single or 4 daily injections of dexamethasone (0.1 or 1 mg/kg). Food intake and weight gain were recorded, and plasma leptin, brain contents of serotonin (5-hydroxytryptamine; 5-HT), 5-hydroxy-indole-acetic acid (5-HIAA) and the raphe expression of tryptophan hydroxylase (TPH), monoamine oxidase A (MAO-A) and 5-HT reuptake transporter (5-HTT) genes were examined. A single injection of dexamethasone did not acutely affect food intake, but cumulative food intake and weight gain were suppressed dose-dependently by daily injections of dexamethasone. Both a single and repeated injections of dexamethasone elevated plasma leptin in a dose dependent manner. 5-HT contents in the hypothalamus was decreased, but 5-HIAA increased, both by a single and repeated dexamethasone. A single injection of dexamethasone did not affect mRNA expressions of TPH, MAO-A and 5-HTT genes, but repeated dexamethasone increased them in the dorsal raphe nucleus. These results suggest that plasma leptin may play a role in dexamethasone-induced anorexia. Additionally, increased expression of MAO-A and 5-HTT genes by repeated dexamethasone appears to be implicated in decreases of the brain 5-HT contents.

Chronic food restriction in young rats results in depression- and anxiety-like behaviors with decreased expression of serotonin reuptake transporter

Evidence of semi-starvation is commonly found in patients with eating disorders. This study was conducted to examine the adverse effects of chronic caloric restriction in young rats, since there have been increasing incidence of eating disorders especially among young populations. Food restriction group was supplied daily with 50% of chow consumed by its ad libitum fed control group from postnatal day 28. After 5 weeks of food restriction, brain contents of serotonin (5-hydroxy-tryptamine; 5-HT) and its metabolite 5-hydroxyindol acetic acid were analyzed by high-performance liquid chromatography and mRNA expression of 5-HT reuptake transporter (5-HTT) by in situ hybridization. Plasma corticosterone levels were determined by radioimmunoassay. Behavioral assessments were performed with Porsolt swim test for depressive behavior and with elevated plus maze test for anxiety. Five weeks of food restriction markedly increased plasma level of corticosterone, and significantly decreased 5-HT turnover rates in the hippocampus and the hypothalamus. 5-HTT mRNA expression decreased in the raphe nucleus of food restricted rats compared with free fed controls. Immobility time during the swim test increased in the food restricted group, compared to the control group. Food restricted rats spent more time in the closed arms, less time in the open arms, of elevated plus maze compared with control rats. These results suggest that chronic caloric restriction in young rats may lead to the development of depressive and/or anxiety disorders, likely, in relation with dysfunction of brain 5-HT system.

Transient alterations in neurotransmitter levels during a critical period of neural development in coho salmon (Oncorhyncus kisutch)

The time of parr-smolt transformation (PST) in salmon is a critical period of brain development during which the olfactory imprinting on the natal stream takes place. PST is associated with a surge of plasma thyroxine. We report here similar surges in the brain content of serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), dopamine (DA), norepinephrine (NE), and glutamine (Gln). Other putative neurotransmitters, such as glutamate and aspartate show no such change which gamma-amino-butyric acid (GABA) shows a minor elevation.

Altered serotonin metabolism in depressed patients with Parkinson's disease

Depression is a common symptom in patients with Parkinson's disease. It is not related to the severity of the motor symptoms or changes in dopamine metabolism and does not improve on treatment with dopamine agonists. Alterations in serotonin metabolism are found in primary (endogenous) depression. The brain content of serotonin in Parkinson's disease is also reduced, but this has not been related to any manifestation of the disorder. We found that the CSF content of the major metabolite of serotonin, 5-hydroxyindoleacetic acid, was lower in depressed than in nondepressed parkinsonians. The data suggest that the alterations in serotonin metabolism in Parkinson's disease identify a subgroup of patients who are prone to depression.

The antagonizing effect of aspartic acid on the brain levels of monoamines and free amino acids during the development of tolerance to and physical dependence on morphine

Since it has been shown in previous study that aspartic acid prevents the development of physical dependence on and tolerance to morphine and antagonizes the abstinence syndrom signs, the biochemical bases of that prevention were investigated in the present study. The brain contents of serotonin, DA, NA, and free amino acids of the rats given aspartic acid and morphine separately and in combination were determined. It has been observed that most of the morphine-induced changes in the brain were normalized in the group given aspartic acid and morphine together. The relative ineffectiveness of aspartic acid in normalizing some amino acid levels decreased by morphine was discussed and some logical explanations were found.

Monamines in brain and urine of rats with hereditary hypothalamic diabetes insipidus.

Monoamine levels in brain and urine of homozygous and heterozygous diabetes insipidus (DI) rats (Brattleboro strain) were assessed. Homozygous DI rats had a higher whole brain content of serotonin than their heterozygous littermates. However, when corrected for differences in brain weight, homozygous DI also appeared to have higher brain concentrations of noradrenaline, tyrosine and GABA. The total 24 h excretion of all amines and their precursors was greater in the homozygous than in the heterozygous rats.

The maturation of the circadian rhythm of brain serotonin in the rat

EXISTENCE of a circadian rhythm in the brain contents of serotonin (5-hydroxytryptamine, 5HT) has been reported in the mouse, hamster, rat and cat (1, 2, 3, 4, 5, 6). Serotonin is considered to be primarily localized in the particular neurons in the central nervous system (7) and probably is a central mediator in the mechanisms for inducing sleep (8). It is also suggested that 5HT within the hypothalamus has an active part in the regulation of the hypothalamo-hypophyseal function and, accordingly, plays a role in producing the circadian periodicity of plasma 17-hydroxycorticosteroids (17-OHCS) (9). However, there have been only two systematic studies, to our knowledge, describing the relationship between the circadian rhythm of the brain 5HT content and that of the plasma corticosterone levels in the rat (3, 10). This paper is concerned with the process of the maturation of the circadian rhythm of brain 5HT in the rat in correlation with the sleep-wakefulness pattern and the circadian rhythm of the plasma corticosterone concentration.

Altered sensitivity to footshock and decreased brain content of serotonin following brain lesions in the rat.

Altered sensitivity to footshock and decreased brain content of serotonin following brain lesions in the rat.