• Development and Reproduction
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• v.6 no.2
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• pp.111-115
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• 2002

5-Hydroxytryptamine(5-HT; serotonin) system has been implicated in the modulation of male sexual behaviors and the secretion of reproductive hormones. In human males, selective serotonin re-uptake inhibitors(SSRIs) are known to improve the major male sexual dysfunction, premature ejaculation, through the central nervous system-mediated pathways. As numerous hormone and local factors, 5-HT may have peripheral role in the regulation of male sexual function. The expression of 5-HT receptor subtypes in the target tissue, however, has not been explored yet. The present study was undertaken to test whether the 5-HT receptor subtypes are expressed in the reproductive tissues of male rat, especially in ejaculatory machinery such as seminal vesicle and vas deferens. To do this, reverse transcription-polymerase chain reaction(RT-PCR) and Southern blot analysis were employed. The transcripts for the 1A, 1B and 2C subtypes of 5-HT receptor were amplified in all the tested tissues. The present study demonstrated the expression of 5-HT receptor in the rat ejaculatory machinery, suggesting that 5-HT may play a pivotal role in the male sexual function via not only central pathway but also peripheral route. Further study on the receptor subtype-specific effect and their harmonized mode of action will be needed to establish the understanding of ejaculation mechanism and drug design.

• YAKHAK HOEJI
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• v.55 no.4
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• pp.277-283
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• 2011

Simultaneous monitoring of catecholamines and serotonin with their appropriate extraction from the biological samples is required in order to understand thoroughly the regulation of the central and peripheral nervous system. In the present research the segmented gradient elution with the solid phase extraction using a C18 cartridge rather than the previous isocratic elution with alumina extraction is successfully employed to determine norepinephrine (NE), epinephrine (E), dopamine (DA), serotonin (5HT), 3,4-dihydroxyphenylacetic acid (DOPAC) and 5-hydroxyindoleacetic acid (5HIAA) simultaneously within 20 minutes using 3,4-dihydroxyhydrocinnamic aicd as the internal standard (IS). Linearities were obtained in the concentration range between $5{\times}10^{-6}M$ and $1{\times}10^{-4}M$ for all 7 compounds with detection limits of 0.6~1.9 ${\mu}M$. The present HPLC/ECD method yielded reasonable accuracy (relative error; -1.4~1.1%) and precision (relative standard deviation; 0.4~1.9%) for 9 measurements of the standard solution consisting of NE, E, DA, 5HT, DOPAC and 5HIAA compounds. Recoveries of catecholamines, serotonin and their metabolites from human serum were in the range of 57%~86%. While the concentrations of NE and 5HT in the serum of normal Sprague-Dawley rat were found as $1.4{\times}10^{-6}M$ and $2.6{\times}10^{-6}M$, respectively, the contents of NE and 5HT in the serum of the stressed rat were increased 5.6 times and 1.4 times more, respectively.

• The Korean Journal of Physiology and Pharmacology
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• v.23 no.4
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• pp.271-279
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• 2019

The lamina II, also called the substantia gelatinosa (SG), of the trigeminal subnucleus caudalis (Vc), is thought to play an essential role in the control of orofacial nociception. Glycine and serotonin (5-hydroxytryptamine, 5-HT) are the important neurotransmitters that have the individual parts on the modulation of nociceptive transmission. However, the electrophysiological effects of 5-HT on the glycine receptors on SG neurons of the Vc have not been well studied yet. For this reason, we applied the whole-cell patch clamp technique to explore the interaction of intracellular signal transduction between 5-HT and the glycine receptors on SG neurons of the Vc in mice. In nine of 13 neurons tested (69.2%), pretreatment with 5-HT potentiated glycine-induced current ($I_{Gly}$). Firstly, we examined with a $5-HT_1$ receptor agonist (8-OH-DPAT, $5-HT_{1/7}$ agonist, co-applied with SB-269970, $5-HT_7$ antagonist) and antagonist (WAY-100635), but $5-HT_1$ receptor agonist did not increase $I_{Gly}$ and in the presence of $5-HT_1$ antagonist, the potentiation of 5-HT on $I_{Gly}$ still happened. However, an agonist (${\alpha}$-methyl-5-HT) and antagonist (ketanserin) of the $5-HT_2$ receptor mimicked and inhibited the enhancing effect of 5-HT on $I_{Gly}$ in the SG neurons, respectively. We also verified the role of the $5-HT_7$ receptor by using a $5-HT_7$ antagonist (SB-269970) but it also did not block the enhancement of 5-HT on $I_{Gly}$. Our study demonstrated that 5-HT facilitated $I_{Gly}$ in the SG neurons of the Vc through the $5-HT_2$ receptor. The interaction between 5-HT and glycine appears to have a significant role in modulating the transmission of the nociceptive pathway.

• Journal of Marine Life Science
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• v.8 no.1
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• pp.32-42
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• 2023

Fish reproduction is regulated by various neurohormones secreted from the brain and gonadotropic hormones secreted from the pituitary. Reproduction of eel (Anguilla japonica) is also regulated by these hormones. However, how the neurohormones regulate the secretion of pituitary hormones during sexual maturation is not completely understood. Previous studies have shown that neurohormones such as progesterone (P4), melatonin and serotonin (5-HT) are involved in the regulation of reproductive processes in some fish. In this study, the eel pituitary was primary cultured, and stabilized pituitary cells were treated with P4, 17β-estradiol (E2), melatonin, or 5-HT. The effect of these treatments on the expression of FSHβ, LHβ, GH and SL mRNA was, then, investigated. P4 increased the expression of FSHβ and LHβ in pituitary cells, and melatonin increased the expression of GH and SL as well as FSHβ and LHβ. However, 5-HT did not significantly affect the expression of these mRNA. These results suggest that P4 and melatonin may play some important roles in the early sexual maturation of eels.

• Development and Reproduction
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• v.13 no.4
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• pp.341-351
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• 2009

The effects of serotonin (5-hydroxytryptamine, 5-HT), ecdysone (20-hydroxyecdysone, 20-E) and HCG (human chorionic gonadotropin) on the ovarian maturation of the fleshy shrimp, Fenneropenaeus chinensis were investigated. Adult female fleshy shrimps were injected with 5-HT ($5{\mu}g$/g body weight (BW) or $20{\mu}g$/g BW), 20-E ($5{\mu}g$/g BW, $10{\mu}g$/g BW or $20{\mu}g$/g BW) or HCG (5 IU/g BW or 10 IU/g BW) three times at 5-day intervals and were sacrificed 10 days after the last injection. The effects were compared against an intact control group and sham control group which received the injection of sterile saline solution as a vehicle. 20-E and HCG showed no effectiveness on ovarian maturation in fleshy shrimps. However flesh shrimp given 5-HT of $20{\mu}g$/g BW showed significant increase in gonadosomatic index (GSI) in early spring. The results suggest that treatment of 5-HT of $20{\mu}g$/g BW or more is useful approach for the nursery production of the fleshy shrimp, Fenneropenaeus chinensis aquaculture.

• Bulletin of the Korean Chemical Society
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• v.28 no.2
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• pp.285-291
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• 2007

The 5-HT6 antagonists are mainly related to the treatment of cognitive dysfunction or impairment associated with Alzheimer's disease and schizophrenia. There have been lots of efforts to develop 5-HT6 antagonists. As in our efforts, arylsulfonylpiperazine derivatives 1-3 were designed, synthesized and biologically evaluated against the human recombinant 5-HT6 serotonin receptor. Total 36 compounds were synthesized and the most active compound among the synthesized compounds is compound 2h with an IC50 value of 1.5 μM. The compound 2h is novel as 5-HT6 receptor ligand and could act as lead for the novel 5-HT6 receptor ligands.

• Korean Journal of Biological Psychiatry
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• v.11 no.2
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• pp.146-154
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• 2004

Objective:Attention deficit hyperactivity disorder(ADHD) is the most common childhood psychiatric disorder, affecting 3-5% of school-aged children. Although the biological basis of ADHD is unknown, family studies provide strong evidence that ADHD has a genetic basis. Recent genetic studies have suggested associations between ADHD and serotonin 1B(5HT1B) receptor gene G861C polymorphism. The aim of this study is to test for the association between ADHD and 5HT1B receptor gene G861C polymorphism in Korean population. Method:We processed DNA extraction and genotyping. 106 Korean children with ADHD and their parents were analyzed using the transmission disequilibrium test(TDT) and haplotype-based haplotype relative risk (HHRR). And the ADHD children were compared with 212 age and gender matched normal controls. Results:There was no statistical difference of distributions between ADHD cases and controls. We did not observe any preferential transmission of alleles of 5HT1B receptor gene G861C polymorphism in ADHD. Conclusions:Though there is the possibility of failing to detect small genetic effects, our results show no evidence of an association between ADHD and 5HT1B receptor gene G861C polymorphism in the Korean population and indicate that it is unlikely that the 5HT1B receptor is implicated in the susceptibility to ADHD.

• The Korean Journal of Physiology and Pharmacology
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• v.19 no.6
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• pp.523-531
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• 2015

Serotonin [5-hydroxytryptamine (5-HT)] regulates synaptic plasticity in the visual cortex. Although the effects of 5-HT on plasticity showed huge diversity depending on the ages of animals and species, it has been unclear how 5-HT can show such diverse effects. In the rat visual cortex, 5-HT suppressed long-term potentiation (LTP) at 5 weeks but enhanced LTP at 8 weeks. We speculated that this difference may originate from differential regulation of neurotransmission by 5-HT between the age groups. Thus, we investigated the effects of 5-HT on apha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR)-, ${\gamma}$-aminobutyric acid receptor type A (GABAAR)-, and N-methyl-D-aspartic acid receptor (NMDAR)-mediated neurotransmissions and their involvement in the differential regulation of plasticity between 5 and 8 weeks. AMPAR-mediated currents were not affected by 5-HT at both 5 and 8 weeks. GABAAR-mediated currents were enhanced by 5-HT at both age groups. However, 5-HT enhanced NMDAR-mediated currents only at 8 weeks. The enhancement of NMDAR-mediated currents appeared to be mediated by the enhanced function of GluN2B subunit-containing NMDAR. The enhanced GABAAR- and NMDAR-mediated neurotransmissions were responsible for the suppression of LTP at 5 weeks and the facilitation of LTP at 8 weeks, respectively. These results indicate that the effects of 5-HT on neurotransmission change with development, and the changes may underlie the differential regulation of synaptic plasticity between different age groups. Thus, the developmental changes in 5-HT function should be carefully considered while investigating the 5-HT-mediated metaplastic control of the cortical network.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.5
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• pp.337-343
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• 2010

Long-term potentiation (LTP) and long-term depression (LTD) have both been studied as mechanisms of ocular dominance plasticity in the rat visual cortex. In a previous study, we suggested that a developmental increase in serotonin [5-hydroxytryptamine (5-HT)] might be involved in the decline of LTP, since 5-HT inhibited its induction. In the present study, to further understand the role of 5-HT in a developmental decrease in plasticity, we investigated the effect of 5-HT on the induction of LTD in the pathway from layer 4 to layer 2/3. LTD was inhibited by 5-HT ($10{\mu}M$) in 5-week-old rats. The inhibitory effect was mediated by activation of 5-$HT_2$ receptors. Since 5-HT also regulates the development of visual cortical circuits, we also investigated the role of 5-HT on the development of inhibition. The development of inhibition was retarded by chronic (2 weeks) depletion of endogenous 5-HT in 5-week-old rats, in which LTD was reinstated. These results suggest that 5-HT regulates the induction of LTD directly via activation of 5-$HT_2$ receptors and indirectly by regulating cortical development. Thus, the present study provides significant insight into the roles of 5-HT on the development of visual cortical circuits and on the age-dependent decline of long-term synaptic plasticity.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.7 no.1
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• pp.77-91
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• 1996

In order to elucidate the biological etiology and the effects of comorbidity on biological variables in tic disorders, plasma serotonin (5-hydroxlfryptamine, 5-HT) and 5-hydroxy- indoleacetic acid (5-HIAA) we.e measured in 87 tic disorders and 30 control subjects. The 87 tic disorder were composed of 45 Tourette's disorder(TS), 22 chronic motor tic disorders (CMT) and 20 transient tic disorders (TTD). Among these patients,43 patients were pure tic disorder (PT), 28 subject also had attention deficit hyperactivity disorder (T+ADHD) and 16 subjects had obsessive compulsive disorders (T+ OCD) as comorbid disorders. The results are summarized as follows : 1) Plasma 5-HT levels showed significant positive correlations with plasma 5-HIAA levels (Pennon r=0.77, p<0.05). 2) Plasma 5-HT and 5-HIAA levels showed no significant correlation with age in tic disorders. 3) Plasma 5-HIAA and 5-HT levels showed no significant correlations with age in control subjects. 4) There was significant difference in plasma 5-HT levels among TS, CMT, TTD and control groups (ANOVA F=34.48, df=3, 113, p<0.01), and post-hoc test using Scheffe method showed significant differences between control and TS, control and CMT, control and ITD groups. But, post-hoc test showed no significant differences between TS and CMT, TS and TTD, CMT and TTD groups. 5) There was significant difference in plasma 5-HIAA levels among TS, CMT, TTD and control groups (ANOVA F=26.48, df=3, 113, p<0.01), and post-hoc test using Scheffe method showed significant differences between control and TS, control and CMT, control and TTD groups. But, post-hoc test showed no significant differences between TS and CMT, TS and TTD, CMT and TID groups.f) There was significant difference in plasma 5-HT and 5-HIAA levels among PT, T+ADHD, T+OCD and contol groups (ANOVA 5-HT, F=37.59, df=3, 113, p<0.01, 5-HIAA, F=27.37, df=3, 113, p<0.01), and post-hoc test using Scheffe method showed signiscant differences between control and PT, control and T+ADHD and control and T+OCB. But, post-hoc test showed no significant differences between PT and T+ADHD, PT and T+ OCD and T+ADHD and T+ OCD. These results show that decreased 5-HT and 5-HIAA levels may play a role in the genesis of tic disorders, but these findings have no significant correlations with the severity of tic disorders. And the comorbid disorders of tics may have minimal effects on the biochemical abnormalities. Future studies must be focused on the effects of serotonin agonists and antagonists on tic disorders and molecular biological methodology may enhance to elucidate the mechanisms of these abnormal findings.