5-Hydroxytryptamine:a potential therapeutic target in amyotrophic lateral sclerosis

Previous studies have indicated that the pathogenesis of amyotrophic lateral sclerosis(ALS) is closely linked to 5-hydroxytryptamine(5-HT).To investigate this further,we administered 5-HT receptor antagonists to SOD1*G93A transgenic(ALS mouse model) and wide-type mice.This involved intraperitoneal injections of either granisetron,piboserod,or ritanserin,which inhibit the 5-HT3,5-HT4,and 5-HT2 receptors,respectively.The transgenic mice were found to have fewer5-HT-positive cells in the spinal cord compared with wide-type mice.We found that the administration of granisetron reduced the body weight of the transgenic mice,while piboserod and ritanserin worsened the motor functioning,as assessed using a hanging wire test.However,none of the 5-HT receptor antagonists affected the disease progression.We analyzed the distribution and/or expression of TAR DNA binding protein 43(TDP-43) and superoxide dismutase 1 G93A(SOD1-G93A),which fo rm abnormal aggregates in ALS.We found that the expression of these proteins increased following the administration of all three 5-HT receptor antagonists.In addition,the disease-related mislocalization of TD P-43 to the cytoplasm increased markedly for all three drugs.In ce rtain anatomical regions,the 5-HT receptor antagonists also led to a marked increase in the number of astrocytes and microglia and a decrease in the number of neurons.These results indicate that 5-HT deficiency may play a role in the pathogenesis of amyotrophic lateral sclerosis by inducing the abnormal expression and/or distribution of TDP-43 and SOD1-G93A and by activating glial cells.5-HT co uld therefore be a potential therapeutic target for amyotrophic lateral sclerosis.

Inhibiting 5-hydroxytryptamine receptor 3 alleviates pathological changes of a mouse model of Alzheimer's disease

Extracellular amyloid beta(Aβ) plaques are main pathological feature of Alzheimer’s disease.However,the specific type of neuro ns that produce Aβ peptides in the initial stage of Alzheimer’s disease are unknown.In this study,we found that 5-hydroxytryptamin receptor 3A subunit(HTR3A) was highly expressed in the brain tissue of transgenic amyloid precursor protein and presenilin-1 mice(an Alzheimer’s disease model) and patients with Alzheimer’s disease.To investigate whether HTR3A-positive interneurons are associated with the production of Aβ plaques,we performed double immunostaining and found that HTR3A-positive interneurons were clustered around Aβ plaques in the mouse model.Some amyloid precursor protein-positive or β-site amyloid precursor protein cleaving enzyme-1-positive neurites near Aβ plaques were co-localized with HTR3A interneurons.These results suggest that HTR3A-positive interneurons may partially contribute to the generation of Aβ peptides.We treated 5.0-5.5-month-old model mice with tro pisetron,a HTR3 antagonist,for 8 consecutive weeks.We found that the cognitive deficit of mice was partially reversed,Aβ plaques and neuroinflammation we re remarkably reduced,the expression of HTR3 was remarkably decreased and the calcineurin/nuclear factor of activated T-cell 4 signaling pathway was inhibited in treated model mice.These findings suggest that HTR3A interneurons partly contribute to generation of Aβ peptide at the initial stage of Alzheimer’s disease and inhibiting HTR3 partly reve rses the pathological changes of Alzheimer’s disease.

Tong xie yao fang relieves irritable bowel syndrome in rats via mechanisms involving regulation of 5-hydroxytryptamine and substance P

AIM: To investigate whether the Chinese medicine Tong Xie Yao Fang(TXYF) improves dysfunction in an irritable bowel syndrome(IBS) rat model. METHODS: Thirty baby rats for IBS modeling were separated from mother rats(1 h per day) from days 8 to 21, and the rectum was expanded by angioplasty from days 8 to 12. Ten normal rats were used as normal controls. We examined the effects of TXYF on defection frequency, colonic transit function and smooth muscle contraction, and the expression of 5-hydroxytryptamine(5-HT) and substance P(SP) in colonic and hypothalamus tissues by Western blot and RT-PCT techniques in both normal rats and IBS model rats with characterized visceral hypersensitivity.in normal rats and 4.5 ± 1.58 in IBS model rats(P < 0.001). However, the defecation frequency was significantly decreased(3.0 ± 1.25 vs 4.5 ± 1.58, P < 0.05), while the time(in seconds) of colon transit function was significantly increased(256.88 ± 20.32 vs 93.36 ± 17.28, P < 0.001) in IBS + TXYF group rats than in IBS group rats. Increased colonic smooth muscle tension and contract frequency in IBS model rats were significantly decreased by administration of TXYF. Exogenous agonist stimulants increased spontaneous activity and elicited contractions of colon smooth muscle in IBS model rats, and all of these actions were significantly reduced by TXYF involving 5-HT and SP down-regulation. CONCLUSION: TXYF can modulate the activity of the enteric nervous system and alter 5-HT and SP activities, which may contribute to the symptoms of IBS.

Changes of 5-hydroxytryptamine and tryptophan hydroxylase expression in the ventral horn of spinal cord

Objective To investigate changes of 5-hydroxytryptamine （5-HT） and its synthesis rate-limiting enzyme tryp-tophan hydroxylase （TPH） in the ventral horn of spinal cord after exercise-induced fatigue, and to further discuss the mecha- nism of exercise-induced central fatigue at spinal level. Methods Sixteen healthy adult Wistar rats were randomly divided into 2 groups： exercise-induced fatigue group and control group. Immunohistochemical staining for 5-HT and TPH in the ventral horn were performed and analysized quantitatively. The mean optic densities of 5-HT and TPH positive fibers or terminals were measured by computerized image analyzer. Results Both 5-HT and TPH positive fibers/terminals decreased in the exercise-induced fatigue group. The immunohistochemical staining was weaker and the mean optic densities decreased obviously in the fatigue group compared with those in the control group （P 〈 0.05）. Conclusion 5-HT and TPH in the ventral horn of spinal cord might be involved in exercise-induced fatigue.

Effect of the pineal gland on 5-hydroxytryptamine and γ-aminobutyric acid secretion in the hippocampus of male rats during the summer and winter

Objective:The present study aimed to investigate the effect of seasonal variation on neurotransmitter release in the hippocampus of normal rats and rats with pineal excision.Methods:Two time points,the summer and winter solstice,which are the longest and shortest days of the year,respectively,were selected.Male Spraguee Dawley rats that underwent a sham operation without pineal excision were included as a control group.The concentrations of 5-hydroxytryptamine(5-HT)andγ-aminobutyric acid(GABA)were determined by radioimmunoassays and enzyme-linked immunosorbent assays,respectively.Results:In the winter,the 5-HT and GABA levels in normal rats exhibited a significant difference compared with those in the operation group(P<.01).A difference was also noted in GABA levels between the normal group and the sham operation group(P<.05).The concentrations of 5-HT and GABA in the hippocampal tissues of the normal group exhibited a seasonal rhythm consisting of elevation during the summer and reduction during the winter(P<.01),while the GABA levels in the sham operation group exhibited a significant difference,with elevation during the summer and reduction during the winter(P<.01).In the operation group,GABA showed the same trend(P<.01).Conclusion:The seasonal rhythm of neurotransmitter secretion by the hippocampus(5-HT and GABA)consisted of elevation during the summer and reduction during the winter.During the winter,the pineal gland exhibited a reverse regulatory effect on the secretion of 5-HT and GABA in the hippocampus,and it exhibited seasonal selectivity with regard to the regulation of 5-HT.

Orbitofrontal cortex action of 5-hydroxytryptamine and its receptor in an acute forced swimming stress-induced depression model

BACKGROUND： The orbitofrontal cortex （OFC） is a brain region closely associated with emotion. 5-hydroxytryptamine （5-HT） has been shown to be involved in human depression. OBJECTIVE： To investigate OFC actions and mechanisms of 5-HT and 5-HT1A receptor （5-HT1AR） in stress-induced depression.DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at Laboratory of Neurobiology, College of Life Science, Shaanxi Normal University between May 2006 and March 2008. MATERIALS： 5-HT, p-chlorophenylalanine （PCPA, an inhibitor to tryptophan hydroxylase） and spiperone （5-HT1AR antagonist） were provided by Sigma, USA; rabbit anti-rat 5-HT1AR antibody was provided by Tianjin Haoyang Biological Manufacture. METHODS： A total of 40 male Sprague Dawley rats, aged 3 months, were randomly divided into five groups： control, model, 5-HT, spiperone ＋ 5-HT, and PCPA, with 8 rats in each group. Except for control group, rats in the other four groups were used to establish depression models by forced swimming for 15 minutes. At 30 minutes before forced swimming test, 0.5 pL of 5-HT （12.5 pg/pL）, PCPA （20 pg/pL）, spiperone （1.3 pg/pL） ＋ 5-HT （12.5 pg/pL, 10 minutes later）, and saline were respectively injected into the OFC of 5-HT, PCPA, spiperone ＋ 5-HT, and model groups, respectively. The control group received a saline microinjection into the OFC.MAIN OUTCOME MEASURES： Forced swimming and open field tests were employed to measure animal behaviors, and immunohistochemistry was used to analyze 5-HT1AR expression in the OFC, cingulate cortex, and piriform cortex. RESULTS： （1） Compared with the model group, 5-HT microinjection into the OFC prominently reduced immobility time in the forced swimming test and rearing in open field test （P 〈 0.05）; locomotion and grooming in open field test were increased, although there was no significance （P 〉 0.05）. Furthermore, following PCPA microinjection into the OFC （PCPA ＋ forced swimming stress）, immobility time in forced swimming test increased dramatically （P〈 0.01）, locomotion and rearing in open field test declined （P〈 0.05 and P 〈 0.01, respectively）. Compared with the 5-HT group, 5-HT1AR antagonist （spiperone ＋ 5-HT ＋ forced swimming stress） increased immobility time in forced swimming test （P 〈 0.01）, but decreased locomotion, rearing, and grooming in open field test. （2） Forced swimming stress markedly elevated 5-HT1AR expression in OFC, cingulate cortex, and piriform cortex （P〈 0.05 or P〈 0.01）. CONCLUSION： 5-HT improved stress-induced depression, and 5-HT anti-depression effects are primarily achieved via 5-HT1AR. Stress-induced up regulation of 5-HT1AR expression might be a compensatory mechanism for decreased 5-HT expression.

Role of 5-hydroxytryptamine expression in cerebellar Purkinje cells in obstructive sleep apnea syndrome

In the present study, electrical stimulation to the rat insular cortex induced apnea or respiratory disturbance, reduced amplitude of genioglossal electromyogram, and decreased electromyogram integrals. In addition, arterial blood gas analysis showed arterial blood acidosis, reduced pH values, increased alkali reserve negative values, decreased peripheral blood 5-hydroxytryptamine content, and increased 5-hydroxytryptamine expression in cerebellar Purkinje cells. Following lidocaine injection to block the habenular nucleus, abnormalities in breath, genioglossal electromyogram, and blood gas values disappeared, and peripheral blood 5-hydroxytryptamine content returned to levels prior to electric stimulation. However, 5-hydroxytryptamine expression in cerebellar Purkinje cells remained high. The results suggested that 5-hydroxytryptamine expression in Purkinje cells did not correlate with ventilation function involving insular cortex and habenular nucleus.

5-hydroxytryptamine-mediated apnea caused by the habenular nucleus

5-hydroxytryptamine contributes to the control of activities of the dilator muscle in the upper respiratory tract, and is derived from the raphe nuclei, in which the habenular nucleus exerts a sustaJned inhibitory effect. In the present study, respiratory motion curve of the genJoglossus muscle and peripheral 5-hydroxytryptamine changes were observed following L-glutamate stimulation of the habenular nucleus of adult Wistar rats. Results showed that the rats had apnea and decreased plasma 5-hydroxytryptamine content after the neurons in habenular nucleus were excited. Genioglossus muscle electromyogram amplitude and integral were significantly reduced. The genioglossus myoelectric activity and respiratory motion curve were similar to obstructive sleep apnea syndrome, thus confirming that the habenular nucleus is the key nucleus involved in the pathogenesis of obstructive sleep apnea syndrome, and is the primary regulated center in the raphe nuclei. Stimulation of the habenular nucleus may suppress 5-hydroxytryptamine release and result in apnea, which is similar to obstructive sleep apnea syndrome.

Synthesis and Metabolism of 5-hydroxytryptamine in Peripheral Circulatory System of Suckling Piglets

[ Objective] To find the rule of 5-hydroxytryptamine （5-HT） synthesis and metabolism in peripheral blood of suckling piglets with aging. [ Method ] All of 15 British Large White pigs at 0, 5 and 15 d of age were selected as experimental animals, and their serumal concentrations of L- tryptophan （L-Trp）, 5-HT and 5-hydroxyindoleacetic acid （5-HIAA） in peripheral circulatory system were determined synchronously by reversed- phase high-performance liquid chromatography method with UV. [ Result] The concentration of L-Trp was （16. 92 ± 1.74） iJmol/L at birth, （59.94 ±10.88） iJmol/L at 5 d of age and （70.42± 6.48） μmol/L at 15 d of age. The concentration of 5-HT was （ 12.85 ± 1.79） iJmol/L at birth, （4.81 ±2.05） ijmol/L at 5 d of age and （5.49±1.09） μmol/L at 15 d of age. While 5-HIAA, the metabolic product of 5-HT, was not detected at all the samples selected. [ Conclusion] The L-Trp concentration of suckling piglets increase significantly with aging （ P 〈0. 05）. While the concentra- tion of 5-HT and the conversion ratio of L-Trp to 5-HT are both highest at birth （P〈0.05） and keep stable at 5 and 15 d of age.

Changes of 5-hydroxytryptamine and dopamine contents in brain microvessels and the influence on cerebral edema at early stage of brain injury

The contents of 5-hydroxytryptamine(5-HT)and dopamine(DA) in the brain microvessels(BMVs) at the early stage of rat brain injury were measured by using high performance liquid chromatography with electrochemical detector(HPLC-ECD) and the influence of the

Effects of 5-hydroxytryptamine Receptor on the Reaction of the Lower Esophageal Sphincter Under the Electrical Field Stimulation

In the first and second parts of this study,5-hydroxytryptamine(5HT)receptors,including 5-HT3 and 5-HT4 with the highest expression level,were found in clasp and sling fibres of the lower esophageal sphincter(LES).Specific 5-HT3 and 5-HT4 receptor agonists can induce the contraction effect of clasp and sling fibres of the LES while specific 5-HT7 receptor agonists showed no effects.In the study of this part,the in-vitro muscle tension measurement technology and EFS methods were used to detect the effect of the selective 5-HT receptor antagonist on the clasp and sling fibres of the in-vitro LES under the electrical field stimulation(EFS),and further to ensure the effect of 5-HT receptor in the LES neuroregulatory pathway,and deeply explore the effect of 5-HT receptor in the systolic and diastolic function regulation of the LES.

Ovarian hormone modulates 5-hydroxytryptamine 3 receptors mRNA expression in rat colon with restraint stress-induced bowel dysfunction

AIM: To examine the effects of ovarian hormone on the expression of 5-hydroxytryptamine 3 receptors (5-HT3R) in rat colon of restraint stress-induced bowel dysfunction.METHODS: Twenty-four female Sprague-Dawley rats were randomly divided into three groups of 8 each: sham operation,ovariectomy (OVX) and ovariectomy with estrogen (E2) and progesterone (P) replacement therapy (OVX+E2+P). The rats were subjected to 1-h restraint stress 4 wk after operation.The changes of defecation were monitored by collection of fecal pellets. The gonadal steroids were measured in duplicate by radioimmunoassay (RIA). The expression of 5-HT3R mRNA in the colon was studied by RT-PCR.RESULTS: Compared with sham group and OVX+E2+P group, OVX group showed increase in fecal pellets and decrease in the time of vitreous pellets excretion (P<0.01).Serum levels of E2 and P were suppressed in OVX group and restored following treatment with ovarian steroids (P<0.01),and the levels of 5-HT3R mRNA in the colon of ovariectomized rats were significantly increased, the expression of 5-HT3R mRNA was significantly decreased in hormone replacement therapy group (P<0.01).CONCLUSION: Ovarian hormone plays a role in the regulation of 5-HT3R expressions in restraint stress-induced bowel dysfunction of rats. The interactions between ovarian steroids and gastrointestinal tract may have major pathophysiological implications in 5-HT-related disorders, such as irritable bowel syndrome (IBS).

Role of 5-hydroxytryptamine type 3 receptors in the regulation of anxiety reactions

5-Hydroxytryptamine(5-HT)type 3 receptor(5-HT_(3)R)is the only type of ligand-gated ion channel in the 5-HT receptor family.Through the high permeability of Na+,K+,and Ca2+and activation of subsequent voltage-gated calcium channels(VGCCs),5-HT_(3)R induces a rapid increase of neuronal excitability or the release of neurotransmitters from axon terminals in the central nervous system(CNS).5-HT_(3)Rs are widely expressed in the medial prefrontal cortex(mPFC),amygdala(AMYG),hippocampus(HIP),periaqueductal gray(PAG),and other brain regions closely associated with anxiety reactions.They have a bidirectional regulatory effect on anxiety reactions by acting on different types of cells in different brain regions.5-HT_(3)Rs mediate the activation of the cholecystokinin(CCK)system in the AMYG,and theγ-aminobutyric acid(GABA)“disinhibition”mechanism in the prelimbic area of the mPFC promotes anxiety by the activation of GABAergic intermediate inhibitory neurons(IINs).In contrast,a 5-HT_(3)R-induced GABA“disinhibition”mechanism in the infralimbic area of the mPFC and the ventral HIP produces anxiolytic effects.5-HT_(2)R-mediated regulation of anxiety reactions are also activated by 5-HT_(3)R-activated 5-HT release in the HIP and PAG.This provides a theoretical basis for the treatment of anxiety disorders or the production of anxiolytic drugs by targeting 5-HT_(3)Rs.However,given the circuit specific modulation of 5-HT_(3)Rs on emotion,systemic use of 5-HT_(3)R agonism or antagonism alone seems unlikely to remedy anxiety,which deeply hinders the current clinical application of 5-HT_(3)R drugs.Therefore,the exploitation of circuit targeting methods or a combined drug strategy might be a useful developmental approach in the future.

Effect of 5-hydroxytryptamine Receptor in the Lower Esophageal Sphincter Regulation Mechanism

As a neurotransmitter and avascular active substance,the 5-hydroxytryptamine(5-HT,serotonin)is widely distributed in the central nervous system and surrounding tissues.The 5-HT can play its role by acting on its corresponding 5-HT receptor.Nowadays,the 5-HT receptor can be classified into seven,according to different signal transduction method of receptors,the 5-HT3 receptor belongs to the ligandgated ion channels,while other six 5-HT receptors are involved into the G protein-coupled receptors and play the biological role by binding to specific G protein-coupled receptors(GPCRs)on the surface of the cell membrane.The 5-HT plays an important role in the brain-gut information transmission and studies showed that the physiological stimulations like having meals,and pathological stimulations like ischemia and stress could promote the release of the 5-HT.In the gastrointestinal tract,the 5-HT is closely related to gastrointestinal sensitivity,gastrointestinal movement and secretion regulation,as well as many gastrointestinal dysfunction disorders,such as gastrointestinal power and visceral sensitivity abnormality and abnormalities of brain-gut axis.

Herbal medicines for insomnia through regulating 5-hydroxytryptamine receptors:a systematic review

Insomnia is a common sleep disorder without effective therapy and can affect a person's life.The mechanism of the disease is not completely understood.Hence,there is a need to understand the targets related to insomnia,in order to develop innovative therapies and new compounds.Recently,increasing interest has been focused on complementary and alternative medicines for treating or preventing insomnia.Research into their molecular components has revealed that their sedative and sleep-promoting properties rely on the interactions with various neurotransmitter systems in the brain.In this review,the role of 5-hydroxytryptamine(5-HT)in insomnia development is summarized,while a systematic analysis of studies is conducted to assess the mechanisms of herbal medicines on different 5-HT receptors subtypes,in order to provide reference for subsequent research.

Effects of 5-hydroxytryptamine and 5-hydroxytryptamine 2A/2C agonist on the genioglossus activity and sleep apnea in rats

Background 5-hydroxytryptamine （5-HT） is a common neurotransmitter in the brain which plays an important role in the pathogenesis of sleep apnea.Dysfunction of 5-HT and 5-HT2 receptors may lead to the collapse of the upper airway and the instability of respiratory control, which in turn produce apnea.Genioglossus （GG） is one of the most important oropharyngeal muscles maintaining the upper airway open.The present study aimed to investigate the effects of 5-HT and 5-HT2 receptor on GG activity and the sleep apnea in Sprague-Dawley （SD） rats.Methods Microinjection probes were placed within the fourth ventricle of sixteen SD rats.After recovery for a week, the electromyogram （EMG） of GG was recorded in the anesthetized and vagotomized rats.The changes of GG activity before and after the microinjection of 5-HT or 5-HT2A/2c agonist -2,5-dimethoxy-4-iodoamphetamine hydrochloride （DOI）were observed.Probes were also laid in another eight SD rats.Electroencephalogram （EEG）, EMG of neck muscle and respiration were recorded at the same time a week later.The effects of DOI on the occurrence of sleep apnea were explored.Results Both 5-HT and DOI significantly enhanced the activity of GG just 3 minutes after the completion of injection.The effect of 5-HT disappeared quickly and the effect of DOI lasted for more than 27 minutes.DOI also significantly decreased the post-sigh apnea index in non-rapid-eye-movement （NREM） and rapid-eye-movement （REM） sleep and decreased the spontaneous apnea index only in NREM sleep （P 〈0.05, respectively）.Conclusion 5-HT and 5-HT2A/2c system correlated closely with the pathogenesis of the sleep apnea syndrome and 5-HT receptors may become the target of the drug treatment.

Effects of 5-hydroxytryptamine ascending pathways of dorsal raphe nuclei and habenular nucleus on the respiration and blood pressure of rats

Obstructive sleep apnea syndrome （OSAS） was a disease of breath obstacle happened in the process of sleep. The central mechanism of OSAS has not yet been fully elucidated. Most of studies focused on raphe nuclei and 5-hydroxytryptamine （5-HT）, and showed that brain serotonergic activity might be decreased in OSAS. It is well known that the dorsal and medial raphe nuclei provide almost all the serotonergic innervation to the forebrain. A previous study evaluated the stimulation of the dorsal raphe nuclei （DRN） in the rat inducing mainly pressor and sympathoexcitatory responses.

5-Hydroxytryptamine Changes under Different Pretreatments on Rat Models of Myocardial Infarction and/or Depression

Background：Psychocardiological researches have suggested a central role of 5-hydroxytryptamine （5-HT） on psychocardiological mechanism.This study aimed to further explore the central role of 5-HT and pretreatment effects of XinLingWan on rats with myocardial infarction （M I） and/or depression.Methods：Ninety Sprague-Dawley rats were randomly divided into three groups：MI group,depression group,and MI ＋ depression group （n 30 in each group）.Each group was then divided into three subgroups （n =10 in each subgroup）：a negative control subgroup （NCS）,a Western medicine subgroup （WMS）,and a traditional Chinese medicine subgroup （TCMS）,which were received pretreatment once a day for 4 weeks by saline,20 mg/kg sertraline mixed with 2 ml saline,and 40 mg/kg XingLingWan mixed with 2 ml saline,respectively.Different rat models were established after different pretreatments.Rats were then sacrificed for detection of serum 5-HT,platelet 5-HT,5-HT2.A receptors （5-HT2AR）,and serotonin transporter （SERT）.Data were analyzed by one-way analysis of variance （ANOVA） and least-significant difference （LSD） testing.Results：M I group：compared with NCS,there was a significant increase in WMS and TCMS of serum 5-HT （176.15 ± 11.32 pg/ml vs.334.50 ± 29.09 pg/ml and 474.04 ± 10.86 pg/ml,respectively,both P =0.000）,platelet 5-HT （129.74 ± 27.17 pg/ml vs.322.24 ± 11.60 pg/ml and 340.4 5 ± 17.99 pg/ml,respectively,both P =0.000）;depression group：compared with NCS,there was a significant increase in WMS and TCMS of serum 5-HT （194.69 ± 5.09 pg/ml vs.326.21 ± 39.98 pg/ml and 456.33 ± 23.12 pg/ml,respectively,both P =0.000）,platelet 5-HT （175.15 ± 4.07 pg/ml vs.204.56 ± 18.59 pg/ml and 252.03 ± 22.26 pg/ml,respectively,P =0.004 and P 0.000,respectively）;MI ＋ depression group：compared with NCS,there was a significant increase in both WMS and TCMS of serum 5-HT （182.50 ± 10.23 pg/ml vs.372.55 ± 52.23 pg/ml and 441.76 ± 23.38 pg/ml,respectively,both P =0.000） and platelet 5-HT （180.83 ± 11.08 pg/ml vs.221.12 ± 22.23 pg/ml and 265.37 ± 29.49 pg/ml,respectively,P =0.011 and P =0.000,respectively）.Conclusions：By elevating the amount of 5-HT and modulating 5-HT2AR and SERT levels in serum and platelets,XinLingWan and sertraline were found to exert pretreatment effect on rat models of MI and/or depression.

Bioassay-guided isolation of saikosaponins with agonistic activity on 5-hydroxytryptamine 2C receptor from Bupleurum chinense and their potential use for the treatment of obesity

5-Hydroxytryptamine 2C(5-HT2C) receptor is one of the major targets of anti-obesity agents, due to its role in regulation of appetite. In the present study, the 70% EtO H extract of the roots of Bupleurum chinense was revealed to have agonistic activity on 5-HT2 C receptor, and the subsequent bioassay-guided isolation led to identification of several saikosaponins as the active constituents with 5-HT2 C receptor agonistic activity in vitro and anti-obesity activity in vivo. The new compound, 22-oxosaikosaponin d(1), was determined by extensive spectroscopic analyses(HR-ESI-MS, IR, and 1D and 2D NMR). The primary structure-activity relationship study suggested that the intramolecular ether bond between C-13 and C-28 and the number of sugars at C-3 position were closely related to the 5-HT2 C receptor agonistic activity. Saikosaponin a(3), the main saponin in B. chinense, showed obviously agonistic activity on 5-HT2 C receptor with an EC50 value of 21.08 ± 0.33 μmol×L^(–1) in vitro and could reduce food intake by 39.1% and 69.2%, and weight gain by 13.6% and 16.4%, respectively, at 3.0 and 6.0 mg×kg^(–1) in vivo. This investigation provided valuable information for the potential use of B. chinense as anti-obesity agent.

Association between 5-hydroxytryptamine transporter gene-linked polymorphic region and smoking behavior in Chinese males

Background Tobacco use is the major risk factor for numerous health problems. However, only 5% of smokers can successfully quit without therapy owing to the highly addictive properties of nicotine. The serotoninergic system may be involved in smoking behavior because nicotine increases brain serotonin secretion, nicotine withdrawal decreases serotonin levels, and a selective serotonin reuptake inhibitor antagonizes the response to nicotine withdrawal. Serotonin transporter （5-HTT） is the most important protein, as it adjusts the serotonin concentration in the synaptic cleft. There is a polymorphism in the upstream regulatory region of the 5-HTT gene, named 5-hydroxytryptamine transporter gene-linked polymorphic region （5-HTTLPR）. Compared with the L allele, the S allele of the polymorphism is associated with decreased transcription efficiency of the 5-HTT gene. In this study, we investigated the relationship between this gene polymorphism and smoking behavior in Chinese males. Methods Polymerase chain reaction-restriction fragment length polymorphism （PCR-RFLP） was performed to find 5-HTTLPR gene polymorphisms in 144 smokers and 135 age-matched healthy non-smokers. A questionnaire was completed in all recruited subjects. Results The proportion of L/L （15.3% vs 5.2%） and S/L （50.0% vs 33.3%） genotypes was significantly higher in the smokers than that in the non-smokers （X^2=21.9; P 〈0.01）. The odds ratio （OR） adjusted by age, education, effects of family members and friends who smoke, and alcohol intake was 2.9 （95%CI 1.78-4.80）. In smokers, the number of cigarettes/day （L/L vs S/L vs S/S： 28±12 vs 20±8 vs 16±6, X^2=18.5, P 〈0.01）, smoking index （L/L vs S/L vs S/S： 561±446 vs 393±341 vs 237±201, X^2=12.5, P 〈0.01） and score on the Fagerstrom test for nicotine dependence （FTND） （L/L vs S/L vs S/S： 7.8±1.6 vs 6.2±2.5 vs 3.5±2.1, X2=48.3, P 〈0.01） were significantly higher in smokers with an L/L or S/L genotype than that in the smokers with the S/S genotype. There were no significant differences in the proportion of starting smoking before 20 years old （P=0.219） and those who succeeded in quitting smoking for more than 1 month （P=-0.456） between individuals with different 5-HTTLPR genotypes in smokers. Conclusions 5-HTTLPR polymorphism may be associated with susceptibility to cigarette smoking in Chinese males. The proportion of the L/L and S/L genotype in smokers was higher than that in non-smokers. In smokers, the level of nicotine dependence and resultant cigarettes consumption may be much higher in individuals with an L/L or S/L genotype than those with the S/S genotype.