• The Korean Journal of Physiology and Pharmacology
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• v.15 no.5
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• pp.267-272
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• 2011

A number of studies have demonstrated that 5-hydroxytryptamine (5-HT) can induce muscle contraction or relaxation response and enhance secretion in the gastrointestinal tract via a multiplicity of 5-HT receptor subtypes. In the present study, we investigated the pharmacological characterization of the 5-HT-induced contractile response in longitudinal smooth muscle isolated from the feline ileum. Addition of 5-HT into muscle chambers enhanced the basal tone and spontaneous activity in a concentration-dependent manner. The neurotoxin tetrodotoxin did not alter the 5-HT-induced contraction of the longitudinal muscles. Neither atropine nor guanethidine affected the contraction. The 5-HT agonists, 5-methylserotonin hydrochloride and mosapride, also evoked concentration-dependent contractions. The 5-HT-induced contraction was enhanced by the $5HT_2$ receptor antagonist ketanserin and the $5-HT_3$ receptor antagonist ondansetron but was inhibited by the 5-$HT_1$ receptor antagonist methysergide and 5-$HT_4$ receptor antagonist GR113808. These results indicate that 5-$HT_1$ and 5-$HT_4$ receptors may mediate the contraction of the 5-HT-induced response and 5-$HT_2$ and 5-$HT_3$ receptors may mediate 5-HT-induced relaxation in feline ileal longitudinal smooth muscles.

• The Korean Journal of Physiology and Pharmacology
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• v.21 no.2
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• pp.169-177
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• 2017

Lamotrigine is an antiepileptic drug widely used to treat epileptic seizures. Using whole-cell voltage clamp recordings in combination with a fast drug application approach, we investigated the effects of lamotrigine on 5-hydroxytryptamine $(5-HT)_3$ receptors in NCB-20 neuroblastoma cells. Co-application of lamotrigine ($1{\sim}300{\mu}M$) resulted in a concentration-dependent reduction in peak amplitude of currents induced by $3{\mu}m$ of 5-HT for an $IC_{50}$ value of $28.2{\pm}3.6{\mu}M$ with a Hill coefficient of $1.2{\pm}0.1$. These peak amplitude decreases were accompanied by the rise slope reduction. In addition, $5-HT_3$-mediated currents evoked by 1 mM dopamine, a partial $5-HT_3$ receptor agonist, were inhibited by lamotrigine co-application. The $EC_{50}$ of 5-HT for $5-HT_3$ receptor currents were shifted to the right by co-application of lamotrigine without a significant change of maximal effect. Currents activated by 5-HT and lamotrigine co-application in the presence of 1 min pretreatment of lamotrigine were similar to those activated by 5-HT and lamotrigine co-application alone. Moreover, subsequent application of lamotrigine in the presence of 5-HT and 5-hydroxyindole, known to attenuate $5-HT_3$ receptor desensitization, inhibited $5-HT_3$ receptor currents in a concentration-dependent manner. The deactivation of $5-HT_3$ receptor was delayed by washing with an external solution containing lamotrigine. Lamotrigine accelerated the desensitization process of $5-HT_3$ receptors. There was no voltage-dependency in the inhibitory effects of lamotrigine on the $5-HT_3$ receptor currents. These results indicate that lamotrigine inhibits $5-HT_3$-activated currents in a competitive manner by binding to the open state of the channels and blocking channel activation or accelerating receptor desensitization.

• Korean Journal of Veterinary Research
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• v.56 no.4
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• pp.205-208
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• 2016

The aim of the present study is to investigate the potential influence of obesity as a factor in 5-hydroxytryptamine (5-HT) concentration in myxomatous mitral valve disease (MMVD) dogs. Fifty-five client-owned dogs were enrolled in a randomized trial. Dogs were classified by echocardiography into healthy (control), mild, and moderate to severe MMVD groups. Each group was subclassified by using a 9-point body condition score (BCS); lean (BCS 5-6/9) and obese groups (BCS 7.5-9/9). Dogs with moderate to severe MMVD had lower serotonin (5-HT) concentrations than the control group (p = 0.03). Dogs with moderate to severe MMVD (p = 0.017) had lower serum 5-HT concentrations than the control group in the obese group (BCS 7.5-9/9). Significant difference was found between the lean and obese groups (p = 0.015) which are not consider severe in the MMVD group. These results suggested that 5-HT concentration was decreased with the increasing severity of MMVD, and obesity might be taken into consideration when interpreting the serotonin concentration in MMVD dogs.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.313-313
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• 2010

The performance of polymer photovoltaic cells based on blends of poly(3-hexylyhiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) is strongly influenced by blend composition and thickness. Polymer photovoltaic cells based on bulk-heterojunction have been fabricated with a structure of ITO/poly(3, 4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS)-pentacene/poly (3-hexylthiophene) (P3HT):phenyl-C61-butyric acid methyl ester (PCBM)/Al. We have prepared PEDOT:PSS by dissolving pentacene in N-methylpyrrolidine (NMP) and mixing with PEDOT:PSS. Pentacene was added a maximum concentration of approximately 5.5mg to the PEDOT:PSS solution and sonicated for 10 min. Active layer (P3HT:PCBM) (1:1) was strongly influenced by PEDOT:PSS-pentacene. We have investigated the performance of photovoltaic device with different concentration of P3HT:PCBM (1:1) 2.0wt%, 2.2wt%, 2.4wt% and 2.6wt%, respectively. The photocurrent and power conversion efficiency (PCE) showed a maximum between 2.0wt% and 2.2wt% concentration of P3HT:PCBM. This implied that both morphology and electron transport properties of the layer influenced the performance of the present photovoltaic cells. As the concentration of P3HT:PCBM blends as an active layer was increased, the power conversion efficiency was decreased. P3HT:PCBM layer and PEDOT:PSS-pentacene layer were characterized by work function, UV-visible absorption, atomic force microscopy (AFM), X-ray diffraction (XRD) and scanning electron microscope (SEM).

• YAKHAK HOEJI
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• v.56 no.2
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• pp.86-91
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• 2012

The objective of this study is to examine how different concentration of neurotransmitters in plasma between patients with dementia and normal people regarding the inhalation of lavender oil. This study subjects were 9 elderly patients with dementia who live in nursing home and 9 normal women. Before and after inhalation, they were collected blood sample. Norepinephrine (NE), serotonin (5-HT), dopamine (DA), and r-aminobutyric acid (GABA) concentration analysis were performed. Before inhalation, dementia patients were significantly different with the normal group in GABA and DA, NE. Following inhalation in experimental group, dementia patients and normal group were only significantly increased in 5-HT. But it did not significantly change in the other neurotransmitters. After inhalation, dementia patients were significantly different with the normal group in GABA and 5-HT. This result suggests that the increase of 5-HT release by the inhalation of lavender oil related to reduce the behavioral and psychological symptoms of dementia.

• The Journal of Korean Medicine
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• v.24 no.4
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• pp.82-86
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• 2003

Objective : To examine the inhibition of 5-Hydroxytryptamine(5-HT) induced vasocontraction of the water extract of Acanthopanax senticosus Harms roots (ASR) on rat thoracic Aorta and mesenteric artery with and without endothelium. Methods : Segments of thoracic aorta and mesenteric artery obtained from rats immediately after delivery were mounted in organ baths superfused on a polygraph. Results : We found that the thoracic aorta segments responded to the water extract of ASR with a dose-dependent and concentration-dependent vasorelaxation. 5-HT produced a concentration-dependent contraction of the thoracic aorta and mesenteric artery. At high concentrations of ASR, the inhibition responses were 93.7% (Jang-su), 93.5% (Heok-ryong-kang-sung), 92.8% (Mt. Back-doo), and 83.5% (Yeon-byun) of the maximum 5-HT induced contraction. At high concentrations of ASR, the relaxational response at thoracic aorta and mesenteric artery wi1h endothelium were 95.2% and 94.6%; without endothelium were 93.5% and 92.5% of 1he maximum 5-HT induced contraction. Conclusions : In conclusion, the effect of water extract of ASR had potent inhibition at 5-HT and the effect of ASR in isolated thoracic aorta and mesenteric artery showed dose-dependent inhibition but endothelium-independent response.

• Journal of Animal Science and Technology
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• v.63 no.2
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• pp.453-460
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• 2021

Oxytocin (OXT) and serotonin (5-HT) are essential neurotransmitters associated with the behavior of animals. Recently, we found that the plasma concentration of OXT is positively correlated with horse docility and friendliness toward humans. However, the relationships between the neurotransmitters and other temperaments such as fearfulness, dominance, and trainability are unknown. This study aimed to identify whether the plasma concentration of OXT or 5-HT is correlated with fearfulness, dominance, and trainability of horses. Blood samples of 34 horses were collected at the Horse Industry Complex Center of Jeonju Kijeon College. The concentration of OXT and 5-HT was measured in the plasma samples using enzyme-linked immunosorbent assays. The fearfulness, dominance, and trainability of horses were scored by three professors who were very familiar with the horses. One-way analysis of variance with the least significant difference post-hoc analysis was used to compare the scores for fearfulness and dominance among groups. The trainability of horses was compared using the student t-test. The 5-HT was negatively correlated with dominance, but it had no relation with fearfulness. The OXT appeared to be negatively correlated with fearfulness and dominance in horses. Furthermore, OXT was positively correlated with the trainability of horses. Additionally, 5-HT appeared to enhance trainability. In conclusion, the concentration of OXT or 5-HT in horse blood plasma can be used as a biomarker to monitor the fearfulness, dominance, or trainability of horses.

• Journal of Ginseng Research
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• v.16 no.3
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• pp.183-189
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• 1992

Effect of the standardized ginseng extract(G115) on the central monoaminergic systems were investigated in comparison with that of halcperidol in rats. Immediately after sacrificed by decapitation, the strlata and frontal cortex were removerl. Concentations of the monoamines dopamine and serctorLin and their metabolites were deterinintd by HPLC-EC. G115 increased the concentration of 5-HIAA and DOPAC/UA ratio in striatum. However, dopaminrrgic neuronal activities were not affected by G115 that decreased the concentratio,Is of 5-HT and 5-HIAA in frontal cortex. G115 in combination with apomorphine significantly irlcreased the concentration of DA and S-HT but decreased the DO PAC/DA ratio and 5-HIAA/5-HT ratio only in frontal cortex. These results suggest that G115 like HPD inhibits the activity of nigrostriatal dopamine neuron in striatum. However, unlike HPD it activates central monoaminergic neuron activity in frontal cortex.

• The Korean Journal of Physiology and Pharmacology
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• v.23 no.5
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• pp.419-426
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• 2019

Mosapride accelerates gastric emptying by acting on 5-hydroxytryptamine type 4 ($5-HT_4$) receptor and is frequently used in the treatment of gastrointestinal (GI) disorders requiring gastroprokinetic efficacy. We tested the effect of mosapride on 5-hydroxytryptamine type 3 ($5-HT_3$) receptor currents because the $5-HT_3$ receptors are also known to be expressed in the GI system and have an important role in the regulation of GI functions. Using the whole-cell voltage clamp method, we compared the currents of the $5-HT_3$ receptors when 5-HT was applied alone or was co-applied with mosapride in cultured NCB-20 cells known to express $5-HT_3$ receptors. The $5-HT_3$ receptor current amplitudes were inhibited by mosapride in a concentration-dependent manner. Mosapride blocked the peak currents evoked by the application of 5-HT in a competitive manner because the $EC_{50}$ shifted to the right without changing the maximal effect. The rise slopes of $5-HT_3$ receptor currents were decreased by mosapride. Pre-application of mosapride before co-application, augmented the inhibitory effect of mosapride, which suggests a closed channel blocking mechanism. Mosapride also blocked the opened $5-HT_3$ receptor because it inhibited the $5-HT_3$ receptor current in the middle of the application of 5-HT. It accelerated desensitization of the $5-HT_3$ receptor but did not change the recovery process from the receptor desensitization. There were no voltage-, or use-dependency in its blocking effects. These results suggest that mosapride inhibited the $5-HT_3$ receptor through a competitive blocking mechanism probably by binding to the receptor in closed state, which could be involved in the pharmacological effects of mosapride to treat GI disorders.

• The Korean Journal of Physiology and Pharmacology
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• v.22 no.5
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• pp.585-595
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• 2018

Amitriptyline, a tricyclic antidepressant, is commonly used to treat depression and neuropathic pain, but its mechanism is still unclear. We tested the effect of amitriptyline on 5-hydroxytryptamine 3 ($5-HT_3$) receptor currents and studied its blocking mechanism because the clinical applications of amitriptyline overlapped with $5-HT_3$ receptor therapeutic potentials. Using a whole-cell voltage clamp method, we recorded the currents of the $5-HT_3$ receptor when 5-HT was applied alone or co-applied with amitriptyline in cultured NCB-20 neuroblastoma cells known to express $5-HT_3$ receptors. To elucidate the mechanism of amitriptyline, we simulated the $5-HT_3$ receptor currents using Berkeley $Madonna^{(R)}$ software and calculated the rate constants of the agonist binding and receptor transition steps. The $5-HT_3$ receptor currents were inhibited by amitriptyline in a concentration-dependent, voltage-independent manner, and a competitive mode. Amitriptyline accelerated the desensitization of the $5-HT_3$ receptor. When amitriptyline was applied before 5-HT treatment, the currents rose slowly until the end of 5-HT treatment. When amitriptyline was co-applied with 5-HT, currents rose and decayed rapidly. Peak current amplitudes were decreased in both applications. All macroscopic currents recorded in whole cell voltage clamping experiments were reproduced by simulation and the changes of rate constants by amitriptyline were correlated with macroscopic current recording data. These results suggest that amitriptyline blocks the $5-HT_3$ receptor by close and open state blocking mechanisms, in a competitive manner. We could expand an understanding of pharmacological mechanisms of amitriptyline related to the modulation of a $5-HT_3$ receptor, a potential target of neurologic and psychiatric diseases through this study.