RESUMO

Colorectal cancer (CRC) is a leading cause of cancer-related mortality worldwide. Serotonin (5-HT) is a biogenic monoamine that acts as a neurotransmitter in the central nervous system and as a paracrine, exocrine, or endocrine messenger in peripheral tissues. In this study, we hypothesized that inhibition of serotonin signaling using 5-HT receptor 2B (HTR2B) inhibitors could potentially impede the progression of CRC. We treated CT26 and COLO-205 cells with SB204741, an inhibitor of HTR2B, and evaluated CRC cell proliferation and migration. We then evaluated the effects of HTR2B inhibition in a xenograft mouse model of human colorectal cancer. We also evaluated the role of a novel inhibitor, GM-60186, using both in vitro and in vivo models. RNA sequencing analysis was performed to elucidate the underlying mechanism of the anti-tumor effects of pharmacological inhibition of HTR2B on CRC. In both CRC cell lines and xenograft mouse models, we show that pharmacological inhibition of HTR2B with SB204741 and GM-60186 significantly inhibits CRC cell proliferation and migration. HTR2B inhibition leads to the suppression of extracellular signal-regulated kinase (ERK) signaling, a critical pathway in CRC pathogenesis. Notably, transcriptomic analysis reveals distinct gene expression changes associated with HTR2B inhibition, providing insight into its therapeutic potential. In this study, we found that pharmacological inhibition of HTR2B suppressed CRC proliferation via ERK signaling. In addition, we proposed a novel HTR2B inhibitor for the treatment of CRC. This study highlights the potential role of HTR2B signaling in CRC. These inhibitors may contribute to new therapeutics for CRC treatment.

Assuntos

Movimento Celular , Proliferação de Células , Neoplasias Colorretais , Sistema de Sinalização das MAP Quinases , Receptor 5-HT2B de Serotonina , Serotonina , Animais , Neoplasias Colorretais/patologia , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/metabolismo , Humanos , Proliferação de Células/efeitos dos fármacos , Receptor 5-HT2B de Serotonina/metabolismo , Linhagem Celular Tumoral , Serotonina/metabolismo , Serotonina/farmacologia , Movimento Celular/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Camundongos , Ensaios Antitumorais Modelo de Xenoenxerto , Camundongos Nus , Camundongos Endogâmicos BALB C , Antagonistas do Receptor 5-HT2 de Serotonina/farmacologia , Transdução de Sinais/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos

RESUMO

Recent evidence indicates that neuronal activity within the claustrum (CLA) may be central to cellular and behavioral responses to psychedelic hallucinogens. The CLA prominently innervates many cortical targets and displays exceptionally high levels of serotonin (5-HT) binding. However, the influence of serotonin receptors, prime targets of psychedelic drug action, on CLA activity remains unexplored. We characterize the CLA expression of all known 5-HT subtypes and contrast the effects of 5-HT and the psychedelic hallucinogen, 2,5-dimethoxy-4-iodoamphetamine (DOI), on excitability of cortical-projecting CLA neurons. We find that the CLA is particularly enriched with 5-HT2C receptors, expressed predominantly on glutamatergic neurons. Electrophysiological recordings from CLA neurons that project to the anterior cingulate cortex (ACC) indicate that application of 5-HT inhibits glutamate receptor-mediated excitatory postsynaptic currents (EPSCs). In contrast, application of DOI stimulates EPSCs. We find that the opposite effects of 5-HT and DOI on synaptic signaling can both be reversed by inhibition of the 5-HT2C, but not 5-HT2A, receptors. We identify specific 5-HT receptor subtypes as serotonergic regulators of the CLA excitability and argue against the canonical role of 5-HT2A in glutamatergic synapse response to psychedelics within the CLA-ACC circuit.

Assuntos

Anfetaminas , Claustrum , Potenciais Pós-Sinápticos Excitadores , Alucinógenos , Receptores de Serotonina , Serotonina , Animais , Serotonina/farmacologia , Serotonina/metabolismo , Alucinógenos/farmacologia , Anfetaminas/farmacologia , Claustrum/efeitos dos fármacos , Claustrum/fisiologia , Receptores de Serotonina/metabolismo , Receptores de Serotonina/efeitos dos fármacos , Potenciais Pós-Sinápticos Excitadores/efeitos dos fármacos , Potenciais Pós-Sinápticos Excitadores/fisiologia , Masculino , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/fisiologia , Camundongos , Camundongos Endogâmicos C57BL

RESUMO

5-Hydroxytryptamine (5-HT) is an inhibitory neurotransmitter widely distributed in mammalian tissues, exerting its effects through binding to various receptors. It plays a crucial role in the proliferation of granulosa cells (GCs) and the development of follicles in female animals, however, its effect on porcine follicle development is not clear. The aim of this study is to investigate the expression of 5-HT and its receptors in various parts of the pig ovary, as well as the effect of 5-HT on porcine follicular development by using ELISA, quantitative real-time PCR (qPCR) and EdU assays. Firstly, we examined the levels of 5-HT and its receptors in porcine ovaries, follicles, and GCs. The findings revealed that the expression of different 5-HT receptors varied among follicles of different sizes. To investigate the relationship between 5-HT and its receptors, we exposed the GCs to 5-HT and found a decrease in 5-HT receptor expression compared to the control group. Subsequently, the treatment of GCs with 0.5 µM, 5 µM, and 50 µM 5-HT showed an increase in the expression of cell cycle-related genes, and EdU results indicated cell proliferation after the 0.5 µM 5-HT treatment. Additionally, the expression of genes involved in E2 synthesis was examined after the treatment of granulosa cells with 0.5 µM 5-HT. The results showed that CYP19A1 and HSP17ß1 expression was decreased. These results suggest that 5-HT might affect the development of porcine follicle by promoting the proliferation of GCs and inhibiting the synthesis of estrogen. This provides a new finding for exploring the effect of 5-HT on follicular development, and lays a foundation for further research on the mechanism of 5-HT in follicles.

Assuntos

Proliferação de Células , Células da Granulosa , Folículo Ovariano , Receptores de Serotonina , Serotonina , Animais , Serotonina/farmacologia , Serotonina/metabolismo , Feminino , Suínos , Folículo Ovariano/metabolismo , Folículo Ovariano/efeitos dos fármacos , Folículo Ovariano/crescimento & desenvolvimento , Células da Granulosa/metabolismo , Células da Granulosa/efeitos dos fármacos , Receptores de Serotonina/metabolismo , Receptores de Serotonina/genética , Proliferação de Células/efeitos dos fármacos

RESUMO

Methyl-eugenol (ME) and eugenol (EUG) are phenylpropanoids with vasodilatory effects. While EUG's vasorelaxant effect in human umbilical artery (HUA) is known, their action in veins is unclear. This study aimed to evaluate ME and EUG in human umbilical vein (HUV). Isolated HUV underwent tension recordings. ME and EUG caused 100 % relaxation in HUV, with EC50 values corresponding to: 174.3 ± 7.3 and 217.3 ± 6.2 µM for ME and EUG respectively in presence of K+; 362.3 ± 5.4 and 227.7 ± 4.9 µM for ME and EUG respectively and in presence of serotonin (5-HT). It was observed that in presence of BaCl2 and CaCl2 evoked contractions, ME (800 and 1000 µM) and EUG (1000 and 1400 µM) prevent the contractions. In presence of K+ channel blockers it was observed that ME promoted relaxation compared to its control, except in presence of 4-AP, suggesting a possible Ca2+-dependent K+ channel activation for this molecule; EUG increased all EC50 in presence of the K+ blockers except in presence of TEA 1 mM. Greater pharmacological potency was observed for ME. This study highlights natural substances' effects on HUV contractile parameters, suggesting ME and EUG as potential vasodilators in maintaining fetal oxygenation and venous flow during gestational hypertensive syndromes.

Assuntos

Eugenol , Veias Umbilicais , Vasodilatação , Vasodilatadores , Eugenol/farmacologia , Eugenol/análogos & derivados , Humanos , Vasodilatadores/farmacologia , Vasodilatação/efeitos dos fármacos , Veias Umbilicais/efeitos dos fármacos , Feminino , Relação Dose-Resposta a Droga , Bloqueadores dos Canais de Potássio/farmacologia , Técnicas In Vitro , Serotonina/farmacologia , Serotonina/metabolismo

RESUMO

To better understand mechanisms of serotonin- (5-HT) mediated vasorelaxation, isolated lateral saphenous veins from cattle were assessed for vasoactivity using myography in response to increasing concentrations of 5-HT or selective 5-HT receptor agonists. Vessels were pre-contracted with 1 × 10-4 M phenylephrine and exposed to increasing concentrations of 5-HT or 5-HT receptor agonists that were selective for 5-HT1B, 5-HT2B, 5-HT4, and 5-HT7. Vasoactive response data were normalized as a percentage of the maximum contractile response induced by the phenylephrine pre-contraction. At 1 × 10-7 M 5-HT, a relaxation was observed with an 88.7% decrease (p < 0.01) from the phenylephrine maximum. At 1 × 10-4 M 5-HT, a contraction was observed with a 165% increase (p < 0.01) from the phenylephrine maximum. Increasing concentrations of agonists selective for 5-HT2B, 5-HT4, or 5-HT7 resulted in a 27%, 92%, or 44% (p < 0.01) decrease from the phenylephrine maximum, respectively. Of these 5-HT receptor agonists, the selective 5-HT4 receptor agonist resulted in the greatest potency (-log EC50) value (6.30) compared with 5-HT2B and 5-HT7 receptor agonists (4.21 and 4.66, respectively). To confirm the involvement of 5-HT4 in 5-HT-mediated vasorelaxation, blood vessels were exposed to either DMSO (solvent control) or a selective 5-HT4 antagonist (1 × 10-5 M) for 5-min prior to the phenylephrine pre-contraction and 5-HT additions. Antagonism of the 5-HT4 receptor attenuated the vasorelaxation caused by 5-HT. Approximately 94% of the vasorelaxation occurring in response to 5-HT could be accounted for through 5-HT4, providing strong evidence that 5-HT-mediated vasorelaxation occurs through 5-HT4 activation in bovine peripheral vasculature.

Assuntos

Veia Safena , Serotonina , Vasodilatação , Animais , Bovinos , Vasodilatação/efeitos dos fármacos , Vasodilatação/fisiologia , Veia Safena/metabolismo , Veia Safena/efeitos dos fármacos , Veia Safena/fisiologia , Serotonina/farmacologia , Receptores de Serotonina/metabolismo , Receptores 5-HT4 de Serotonina/metabolismo , Fenilefrina/farmacologia , Agonistas do Receptor de Serotonina/farmacologia , Masculino

RESUMO

Serotonin or 5-hydroxytryptamine (5-HT) is a monoamine that plays a critical role in insulin secretion, energy metabolism, and mitochondrial biogenesis. However, the action of serotonin in insulin production and secretion by pancreatic ß cells has not yet been elucidated. Here, we investigated how exogenous nanomolar serotonin concentrations regulate insulin synthesis and secretion in rat insulinoma INS-1E cells. Nanomolar serotonin concentrations (10 and 50 nM) significantly increased insulin protein expression above the constant levels in untreated control cells and decreased insulin protein levels in the media. The reductions in insulin protein levels in the media may be associated with ubiquitin-mediated protein degradation. The levels of membrane vesicle trafficking-related proteins including Rab5, Rab3A, syntaxin6, clathrin, and EEA1 proteins were significantly decreased by serotonin treatment compared to the untreated control cells, whereas the expressions of Rab27A, GOPC, and p-caveolin-1 proteins were significantly reduced by serotonin treatment. In this condition, serotonin receptors, Gαq-coupled 5-HT2b receptor (Htr2b), and ligand-gated ion channel receptor Htr3a were significantly decreased by serotonin treatment. To confirm the serotonylation of Rab3A and Rab27A during insulin secretion, we investigated the protein levels of Rab3A and Rab27A, in which transglutaminase 2 (TGase2) serotonylated Rab3A but not Rab27A. The increases in ERK phosphorylation levels were consistent with increases in the expression of p-Akt. Also, the expression level of the Bcl-2 protein was significantly increased by 50 and 100 nM serotonin treatment compared to the untreated control cells, whereas the levels of Cu/Zn-SOD and Mn-SOD proteins decreased. These results indicate that nanomolar serotonin treatment regulates the insulin protein level but decreases this level in media through membrane vesicle trafficking-related proteins (Rab5, Rab3A, syntaxin6, clathrin, and EEA1), the Akt/ERK pathway, and Htr2b/Htr3a in INS-1E cells.

Assuntos

Secreção de Insulina , Insulina , Insulinoma , Serotonina , Animais , Serotonina/metabolismo , Serotonina/farmacologia , Ratos , Insulinoma/metabolismo , Insulinoma/patologia , Secreção de Insulina/efeitos dos fármacos , Insulina/metabolismo , Linhagem Celular Tumoral , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/metabolismo

RESUMO

BACKGROUND & AIMS: Portal hypertension (PH) is one of the most frequent complications of chronic liver disease. The peripheral 5-hydroxytryptamine (5-HT) level was increased in cirrhotic patients. We aimed to elucidate the function and mechanism of 5-HT receptor 1A (HTR1A) in the portal vein (PV) on PH. METHODS: PH models were induced by thioacetamide injection, bile duct ligation, or partial PV ligation. HTR1A expression was detected using real-time polymerase chain reaction, in situ hybridization, and immunofluorescence staining. In situ intraportal infusion was used to assess the effects of 5-HT, the HTR1A agonist 8-OH-DPAT, and the HTR1A antagonist WAY-100635 on portal pressure (PP). Htr1a-knockout (Htr1a-/-) rats and vascular smooth muscle cell (VSMC)-specific Htr1a-knockout (Htr1aΔVSMC) mice were used to confirm the regulatory role of HTR1A on PP. RESULTS: HTR1A expression was significantly increased in the hypertensive PV of PH model rats and cirrhotic patients. Additionally, 8-OH-DPAT increased, but WAY-100635 decreased, the PP in rats without affecting liver fibrosis and systemic hemodynamics. Furthermore, 5-HT or 8-OH-DPAT directly induced the contraction of isolated PVs. Genetic deletion of Htr1a in rats and VSMC-specific Htr1a knockout in mice prevented the development of PH. Moreover, 5-HT triggered adenosine 3',5'-cyclic monophosphate pathway-mediated PV smooth muscle cell contraction via HTR1A in the PV. We also confirmed alverine as an HTR1A antagonist and demonstrated its capacity to decrease PP in rats with thioacetamide-, bile duct ligation-, and partial PV ligation-induced PH. CONCLUSIONS: Our findings reveal that 5-HT promotes PH by inducing the contraction of the PV and identify HTR1A as a promising therapeutic target for attenuating PH. As an HTR1A antagonist, alverine is expected to become a candidate for clinical PH treatment.

Assuntos

Hipertensão Portal , Camundongos Knockout , Pressão na Veia Porta , Veia Porta , Receptor 5-HT1A de Serotonina , Agonistas do Receptor 5-HT1 de Serotonina , Animais , Feminino , Humanos , Masculino , Camundongos , Ratos , 8-Hidroxi-2-(di-n-propilamino)tetralina/farmacologia , AMP Cíclico/metabolismo , Modelos Animais de Doenças , Hipertensão Portal/metabolismo , Hipertensão Portal/genética , Hipertensão Portal/fisiopatologia , Hipertensão Portal/etiologia , Ligadura , Cirrose Hepática/metabolismo , Cirrose Hepática/genética , Cirrose Hepática/patologia , Cirrose Hepática Experimental/metabolismo , Cirrose Hepática Experimental/genética , Cirrose Hepática Experimental/patologia , Cirrose Hepática Experimental/induzido quimicamente , Cirrose Hepática Experimental/fisiopatologia , Camundongos Endogâmicos C57BL , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/patologia , Miócitos de Músculo Liso/metabolismo , Miócitos de Músculo Liso/efeitos dos fármacos , Miócitos de Músculo Liso/patologia , Piperazinas/farmacologia , Pressão na Veia Porta/efeitos dos fármacos , Veia Porta/metabolismo , Piridinas/farmacologia , Ratos Sprague-Dawley , Ratos Wistar , Receptor 5-HT1A de Serotonina/metabolismo , Receptor 5-HT1A de Serotonina/genética , Serotonina/metabolismo , Serotonina/farmacologia , Agonistas do Receptor 5-HT1 de Serotonina/farmacologia , Antagonistas do Receptor 5-HT1 de Serotonina/farmacologia , Transdução de Sinais , Tioacetamida/toxicidade

RESUMO

BACKGROUND: We previously found that cardioplegic arrest and cardiopulmonary bypass are associated with altered coronary arteriolar response to serotonin in patients undergoing cardiac surgery. In this study, we investigated the effects of hypertension on coronary microvascular vasomotor tone in response to serotonin and alterations in serotonin receptor protein expression in the setting of cardioplegic arrest and cardiopulmonary bypass. METHODS: Coronary arterioles were dissected from harvested pre- and post-cardioplegic arrest and cardiopulmonary bypass right atrial tissue samples of patients undergoing cardiac surgery with normotension, well-controlled hypertension, and uncontrolled hypertension. Vasomotor tone was assessed by video-myography, and protein expression was measured with immunoblotting. RESULTS: Pre-cardioplegic arrest and cardiopulmonary bypass, serotonin induced moderate relaxation responses of coronary arterioles in normotension and well-controlled hypertension patients, whereas serotonin caused moderate contractile responses in uncontrolled hypertension patients. Post-cardioplegic arrest and cardiopulmonary bypass, serotonin caused contractile responses of coronary arterioles in all 3 groups. The post-cardioplegic arrest and cardiopulmonary bypass contractile response to serotonin was significantly higher in the uncontrolled hypertension group compared with the normotension or well-controlled hypertension groups (P < .05). Pre-cardioplegic arrest and cardiopulmonary bypass, expression of the serotonin 1A receptor was significantly lower in the uncontrolled hypertension group compared with the well-controlled hypertension and normotension groups (P = .01 and P < .001). Serotonin 1B receptor expression was higher in the uncontrolled hypertension group compared with the normotension or well-controlled hypertension groups post-cardioplegic arrest and cardiopulmonary bypass (P = .03 and P = .046). CONCLUSION: Uncontrolled hypertension is associated with an increased coronary contractile response of coronary microvessels to serotonin and altered serotonin receptor protein expression after cardioplegic arrest and cardiopulmonary bypass. These findings may contribute to a worse postoperative coronary spasm and worsened recovery of coronary perfusion in patients with uncontrolled hypertension after cardioplegic arrest and cardiopulmonary bypass and cardiac surgery.

Assuntos

Ponte Cardiopulmonar , Vasos Coronários , Hipertensão , Serotonina , Humanos , Ponte Cardiopulmonar/efeitos adversos , Masculino , Feminino , Serotonina/metabolismo , Serotonina/farmacologia , Hipertensão/fisiopatologia , Hipertensão/metabolismo , Hipertensão/etiologia , Pessoa de Meia-Idade , Idoso , Vasos Coronários/fisiopatologia , Arteríolas/metabolismo , Arteríolas/fisiopatologia , Arteríolas/efeitos dos fármacos , Parada Cardíaca Induzida/efeitos adversos , Vasoconstrição/efeitos dos fármacos , Receptores de Serotonina/metabolismo , Vasodilatação/efeitos dos fármacos

RESUMO

We examined the localization of the 5-hydroxytryptamine (5-HT) receptor and its effects on mouse colonic interstitial cells of Cajal (ICCs) using electrophysiological techniques. Treatment with 5-HT increased the pacemaker activity in colonic ICCs with depolarization of membrane potentials in a dose-dependent manner. Hyperpolarization-activated cyclic nucleotide-gated (HCN) channel blockers blocked pacemaker activity and 5-HT-induced effects. Moreover, an adenylate cyclase inhibitor inhibited 5-HT-induced effects, and cell-permeable 8-bromo-cAMP increased the pacemaker activity. Various agonists of the 5-HT receptor subtype were working in colonic ICCs, including the 5-HT4 receptor. In small intestinal ICCs, 5-HT depolarized the membrane potentials transiently. Adenylate cyclase inhibitors or HCN blockers did not show any influence on 5-HT-induced effects. Anoctamin-1 (ANO1) or T-type Ca2+ channel blockers inhibited the pacemaker activity of colonic ICCs and blocked 5-HT-induced effects. A tyrosine protein kinase inhibitor inhibited pacemaker activity in colonic ICCs under controlled conditions but did not show any influence on 5-HT-induced effects. Among mitogen-activated protein kinase (MAPK) inhibitors, a p38 MAPK inhibitor inhibited 5-HT-induced effects on colonic ICCs. Thus, 5-HT's effect on pacemaker activity in small intestinal and colonic ICCs has excitatory but variable patterns. ANO1, T-type Ca2+, and HCN channels are involved in 5-HT-induced effects, and MAPKs are involved in 5-HT effects in colonic ICCs.

Assuntos

Doenças do Colo , Células Intersticiais de Cajal , Animais , Camundongos , Masculino , Serotonina/farmacologia , Células Intersticiais do Testículo , Inibidores de Adenilil Ciclases , Bloqueadores dos Canais de Cálcio , Inibidores de Proteínas Quinases

RESUMO

For most quadrupeds, locomotion involves alternating movements of the fore- and hindlimbs. In birds, however, while walking generally involves alternating movements of the legs, to generate lift and thrust, the wings are moved synchronously with each other. Neural circuits in the spinal cord, referred to as central pattern generators (CPGs), are the source of the basic locomotor rhythms and patterns. Given the differences in the patterns of movement of the wings and legs, it is likely that the neuronal components and connectivity of the CPG that coordinates wing movements differ from those that coordinate leg movements. In this study, we used in vitro preparations of embryonic chicken spinal cords (E11-E14) to compare the neural responses of spinal CPGs that control and coordinate wing flapping with those that control alternating leg movements. We found that in response to N-methyl-D-aspartate (NMDA) or a combination of NMDA and serotonin (5-HT), the intact chicken spinal cord produced rhythmic outputs that were synchronous both bilaterally and between the wing and leg segments. Despite this, we found that this rhythmic output was disrupted by an antagonist of glycine receptors in the lumbosacral (legs), but not the brachial (wing) segments. Thus, our results provide evidence of differences between CPGs that control the wings and legs in the spinal cord of birds.

Assuntos

Geradores de Padrão Central , N-Metilaspartato , Serotonina , Medula Espinal , Animais , Medula Espinal/fisiologia , Embrião de Galinha , Geradores de Padrão Central/fisiologia , Serotonina/metabolismo , Serotonina/farmacologia , N-Metilaspartato/farmacologia , N-Metilaspartato/metabolismo , Asas de Animais/fisiologia , Locomoção/fisiologia , Periodicidade , Membro Posterior/fisiologia , Membro Posterior/inervação , Neurônios Motores/fisiologia , Potenciais de Ação/fisiologia

RESUMO

Depression's link to serotonin dysregulation is well-known. The monoamine theory posits that depression results from impaired serotonin activity, leading to the development of antidepressants targeting serotonin levels. However, their limited efficacy suggests a more complex cause. Recent studies highlight mitochondria as key players in depression's pathophysiology. Mounting evidence indicates that mitochondrial dysfunction significantly correlates with major depressive disorder (MDD), underscoring its pivotal role in depression. Exploring the serotonin-mitochondrial connection, our study investigated the effects of chronic serotonin treatment on induced-pluripotent stem cell-derived astrocytes and neurons from healthy controls and two case study patients. One was a patient with antidepressant non-responding MDD ("Non-R") and another had a non-genetic mitochondrial disorder ("Mito"). The results revealed that serotonin altered the expression of genes related to mitochondrial function and dynamics in neurons and had an equalizing effect on calcium homeostasis in astrocytes, while ATP levels seemed increased. Serotonin significantly decreased cytosolic and mitochondrial calcium in neurons. Electrophysiological measurements evidenced that serotonin depolarized the resting membrane potential, increased both sodium and potassium current density and ultimately improved the overall excitability of neurons. Specifically, neurons from the Non-R patient appeared responsive to serotonin in vitro, which seemed to improve neurotransmission. While it is unclear how this translates to the systemic level and AD resistance mechanisms are not fully elucidated, our observations show that despite his treatment resistance, this patient's cortical neurons are responsive to serotonergic signals. In the Mito patient, evidence suggested that serotonin, by increasing excitability, exacerbated an existing hyperexcitability highlighting the importance of considering mitochondrial disorders in patients with MDD, and avoiding serotonin-increasing medication. Taken together, our findings suggested that serotonin positively affects calcium homeostasis in astrocytes and increases neuronal excitability. The latter effect must be considered carefully, as it could have beneficial or detrimental implications based on individual pathologies.

Assuntos

Astrócitos , Cálcio , Transtorno Depressivo Maior , Células-Tronco Pluripotentes Induzidas , Mitocôndrias , Neurônios , Serotonina , Humanos , Serotonina/metabolismo , Serotonina/farmacologia , Mitocôndrias/metabolismo , Mitocôndrias/efeitos dos fármacos , Células-Tronco Pluripotentes Induzidas/metabolismo , Células-Tronco Pluripotentes Induzidas/efeitos dos fármacos , Astrócitos/metabolismo , Astrócitos/efeitos dos fármacos , Transtorno Depressivo Maior/metabolismo , Neurônios/metabolismo , Neurônios/efeitos dos fármacos , Cálcio/metabolismo , Adulto , Masculino , Feminino , Depressão/metabolismo , Antidepressivos/farmacologia , Transmissão Sináptica/efeitos dos fármacos , Transmissão Sináptica/fisiologia , Pessoa de Meia-Idade

RESUMO

Mosapride (4-amino-5-chloro-2-ethoxy-N-[[4-[(4-fluorophenyl) methyl]-2-morpholinyl]-methyl] benzamide) is a potent agonist at gastrointestinal 5-HT4 receptors. Mosapride is an approved drug to treat several gastric diseases. We tested the hypothesis that mosapride also stimulates 5-HT4 receptors in the heart. Mosapride increased the force of contraction and beating rate in isolated atrial preparations from mice with cardiac overexpression of human 5-HT4-serotonin receptors (5-HT4-TG). However, it is inactive in wild-type mouse hearts (WT). Mosapride was less effective and potent than serotonin in raising the force of contraction or the beating rate in 5-HT4-TG. Only in the presence of cilostamide (1 µM), a phosphodiesterase III inhibitor, mosapride, and its primary metabolite time dependently raised the force of contraction under isometric conditions in isolated paced human right atrial preparations (HAP, obtained during open heart surgery). In HAP, mosapride (10 µM) reduced serotonin-induced increases in the force of contraction. Mosapride (10 µM) shifted the concentration-response curves to serotonin in HAP to the right. These data suggest that mosapride is a partial agonist at 5-HT4-serotonin receptors in HAP.

Assuntos

Benzamidas , Morfolinas , Contração Miocárdica , Receptores 5-HT4 de Serotonina , Agonistas do Receptor 5-HT4 de Serotonina , Receptores 5-HT4 de Serotonina/metabolismo , Animais , Humanos , Benzamidas/farmacologia , Morfolinas/farmacologia , Agonistas do Receptor 5-HT4 de Serotonina/farmacologia , Masculino , Contração Miocárdica/efeitos dos fármacos , Camundongos Transgênicos , Camundongos , Átrios do Coração/efeitos dos fármacos , Átrios do Coração/metabolismo , Serotonina/farmacologia , Serotonina/metabolismo , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Agonistas do Receptor de Serotonina/farmacologia

RESUMO

Flopropione (Flo) has been used for gallstone and urolithiasis as a spasmolytic agent almost exclusively in Japan. According to the package insert, its main mechanism is catechol-O-methyltransferase (COMT) inhibition and anti-serotonergic effect. This is obviously contrary to pharmacological common sense, but it is described that way in pharmacology textbooks and occurs in questions in the National Examination for Pharmacists in Japan. As this is a serious problem in education, we re-examined the action of Flo. The guinea pig ureter was hardly contracted by serotonin, but noradrenaline (NA) elicited repetitive twitch contraction, which was inhibited by Flo. The sphincter of Oddi (SO) exhibited a spontaneous repetitive twitch contraction, which was inhibited by NA and Flo. The inhibitory effect of NA was reversed by α- and ß-blockers, whereas that of Flo was not. Entacapone, a representative COMT inhibitor, did not affect the movement of the ureter and the SO. Nifedipine suppressed carbachol-induced contraction of the taenia coli, spontaneous movement of the SO, and NA-induced contraction of the ureter to almost the same extent, whereas Flo did not inhibit the taenia coli, but inhibited the contraction of the SO and the ureter. The inhibitory pattern of Flo resembled that of the ryanodine receptor agonist 4-chloro-m-cresol and the inositol 1,4,5-trisphosphate (IP3) receptor antagonist 2-aminoethoxydiphenyl borate. It is concluded that COMT inhibition or serotonin inhibition is not involved in the spasmolytic action of Flo. Flo might act on ryanodine receptors and/or IP3 receptors, which are responsible for periodic Ca release from Ca stores, to disrupt coordinated Ca dynamics.

Assuntos

Contração Muscular , Parassimpatolíticos , Propiofenonas , Animais , Cobaias , Parassimpatolíticos/farmacologia , Catecol O-Metiltransferase/farmacologia , Serotonina/farmacologia , Catecóis/farmacologia , Cálcio/farmacologia

RESUMO

New psychoactive substances (NPS) are typically synthesized in clandestine laboratories in an attempt to chemically modify already federally regulated drugs in an effort to circumvent the law. Drugs derived from a phenethylamine pharmacophore, such as 4-chloroamphetamine and 3,4-methylenedioxymethamphetamine (MDMA), reliably induce thermogenesis and serotonergic deficits in the striatum and hippocampus of rodents. 4-methylamphetamine (4-MA), a relative newcomer to the NPS scene, was originally investigated in the mid-1900 s as a potential anorexigenic agent. With its phenethylamine pharmacophore, 4-MA was hypothesized to produce similar toxicological alterations as its chemical analogs. In the present study, three doses (1.0, 2.5, and 5.0 mg/kg, ip.) of 4-MA were administered to rats twice daily for two days. Core temperature data were calculated and analyzed as temperature area under the curve (TAUC). On the second day of dosing, a hypothermic response to 4-MA (2.5 and 5.0 mg/kg) was noted between 0.5 and 2.0 h post-treatment. Only the highest dose of 4-MA decreased body weight on the second day of treatment and maintained this reduction in weight for seven days after treatment ceased. None of the doses of 4-MA evaluated significantly altered serotonin levels in the hippocampus or striatum seven days after final treatment. The present findings demonstrate that the 4-methyl substitution to amphetamine generates a pharmacological and toxicological profile that differs from other similar phenethylamine analogs.

Assuntos

Anfetaminas , Drogas Desenhadas , Metanfetamina , N-Metil-3,4-Metilenodioxianfetamina , Ratos , Animais , Metanfetamina/farmacologia , Serotonina/farmacologia , Drogas Desenhadas/farmacologia , Temperatura , N-Metil-3,4-Metilenodioxianfetamina/farmacologia , Anfetamina/farmacologia , Hipocampo , Serotoninérgicos/farmacologia , Serotoninérgicos/análise

RESUMO

Serotonin-releasing fibers depart from the raphe nuclei to profusely innervate the entire central nervous system, displaying in some brain regions high structural plasticity in response to genetically induced abrogation of serotonin synthesis. Chronic fluoxetine treatment used as a tool to model peri-physiological, clinically relevant serotonin elevation is also able to cause structural rearrangements of the serotonergic fibers innervating the hippocampus. Whether this effect is limited to hippocampal-innervating fibers or extends to other populations of axons is not known. Here, we used confocal imaging and three-dimensional (3-D) modeling analysis to expand our morphological investigation of fluoxetine-mediated effects on serotonergic circuitry. We found that chronic treatment with a behaviorally active dose of fluoxetine affects the morphology and reduces the density of serotonergic axons innervating the medial prefrontal cortex, a brain region strongly implicated in the regulation of depressive- and anxiety-like behavior. Axons innervating the somatosensory cortex were unaffected, suggesting differential susceptibility to serotonin changes across cortical areas. Importantly, a 1-month washout period was sufficient to reverse morphological changes in both the medial prefrontal cortex and in the previously characterized hippocampus, as well as to normalize behavior, highlighting an intriguing relationship between axon density and an antidepressant-like effect. Overall, these results further demonstrate the bidirectional plasticity of defined serotonergic axons and provide additional insights into fluoxetine effects on the serotonergic system.

Assuntos

Fluoxetina , Serotonina , Fluoxetina/farmacologia , Serotonina/farmacologia , Antidepressivos/farmacologia , Hipocampo , Encéfalo

RESUMO

Identifying additional noninvasive biomarkers for affective disorders, such as unipolar major depressive disorder (MDD) and bipolar disorder (BD), could aid in the diagnosis and treatment of these prevalent and debilitating neuropsychiatric conditions. One such candidate biomarker is the loudness dependence of the auditory evoked potential (LDAEP), an event-related potential that measures responsiveness of the auditory cortex to different intensities of sound. The LDAEP has been associated with MDD and BD, including therapeutic response to particular classes of antidepressant drugs, while also correlating with several other neuropsychiatric disorders. It has been suggested that increased values of the LDAEP indicate low central serotonergic neurotransmission, further implicating this EEG measure in depression. Here, we briefly review the literature on the LDAEP in affective disorders, including its association with serotonergic signaling, as well as with that of other neurotransmitters such as dopamine. We summarize key findings on the LDAEP and the genetics of these neurotransmitters, as well as prediction of response to particular classes of antidepressants in MDD, including SSRIs versus noradrenergic agents. The possible relationship between this EEG measure and suicidality is addressed. We also briefly analyze acute pharmacologic studies of serotonin and/or dopamine precursor depletion and the LDAEP. In conclusion, the existing literature suggests that serotonin and norepinephrine may modulate the LDAEP in an opposing manner, and that this event-related marker may be of use in predicting response to chronic treatment with particular pharmacologic agents in the context of affective disorders, such as MDD and BD, including in the presence of suicidality.

Assuntos

Transtorno Depressivo Maior , Serotonina , Humanos , Serotonina/farmacologia , Transtorno Depressivo Maior/tratamento farmacológico , Dopamina/farmacologia , Inibidores Seletivos de Recaptação de Serotonina , Potenciais Evocados Auditivos/fisiologia , Antidepressivos/farmacologia , Antidepressivos/uso terapêutico , Eletroencefalografia

RESUMO

5-HT2 receptors on motoneurones play a critical role in facilitating persistent inward currents (PICs). Although facilitation of PICs can enhance self-sustained firing after periods of excitation, the relationship between 5-HT2 receptor activity and self-sustained firing in human motor units (MUs) has not been resolved. MU activity was assessed from the tibialis anterior of 10 healthy adults (24.9 ± 2.8 years) during two contraction protocols. Both protocols featured steady-state isometric contractions with constant descending drive to the motoneurone pool. However, one protocol also included an additional phase of superimposed descending drive. Adding and then removing descending drive in the middle of steady-state contractions altered MU firing behaviour across the motor pool, where newly recruited units in the superimposed phase were unable to switch off (P = 0.0002), and units recruited prior to additional descending drive reduced their discharge rates (P < 0.0001, difference in estimated marginal means (∆) = 2.24 pulses/s). The 5-HT2 receptor antagonist, cyproheptadine, was then administered to determine whether changes in MU firing were mediated by serotonergic mechanisms. 5-HT2 receptor antagonism caused reductions in MU discharge rate (P < 0.001, ∆ = 1.65 pulses/s), recruitment threshold (P = 0.00112, ∆ = 1.09% maximal voluntary contraction) and self-sustained firing duration (P < 0.0001, ∆ = 1.77s) after the additional descending drive was removed in the middle of the steady-state contraction. These findings indicate that serotonergic neuromodulation plays a key role in facilitating discharge and self-sustained firing of human motoneurones, where adaptive changes in MU recruitment must occur to meet the demands of the contraction. KEY POINTS: Animal and cellular preparations indicate that somato-dendritic 5-HT2 receptors regulate the intrinsic excitability of motoneurones. 5-HT2 receptor antagonism reduces estimates of persistent inward currents in motoneurones, which contribute to self-sustained firing when synaptic inputs are reduced or removed. This human study employed a contraction task that slowly increased (and then removed) the additional descending drive in the middle of a steady-state contraction where marked self-sustained firing occurred when the descending drive was removed. 5-HT2 receptor antagonism caused widespread reductions in motor unit (MU) discharge rates during contractions, which was accompanied by reduced recruitment threshold and attenuation of self-sustained firing duration after the removal of the additional descending drive to motoneurones. These findings support the role that serotonergic neuromodulation is a key facilitator of MU discharge and self-sustained firing of human motoneurones, where adaptative changes in MU recruitment must occur to meet the demands of the contraction.

Assuntos

Receptores 5-HT2 de Serotonina , Serotonina , Adulto , Humanos , Serotonina/farmacologia , Músculo Esquelético/fisiologia , Contração Isométrica/fisiologia , Neurônios Motores/fisiologia , Eletromiografia/métodos , Contração Muscular/fisiologia , Recrutamento Neurofisiológico/fisiologia

RESUMO

Infertility affects 15% of all couples worldwide and 50% of cases of infertility are solely due to male factors. A decrease in motility in the semen is considered one of the main factors that is directly related to infertility. The use of supplementation to improve the overall sperm quality has become increasingly popular worldwide. The purpose of this study was to evaluate whether sperm motility was affected by the combination of serotonin (5-HT), selenium (Se), zinc (Zn), and vitamins D, and E supplementation. Semen samples were incubated for 75 min at 37°C in medium containing varying concentrations of 5-HT, Se, Zn, vitamin D, and E. 5-HT (200 µM), Se (2 µg/ml), Zn (10 µg/ml), vitamin D (100 nM), and vitamin E (2 mmol) have also been shown to increase progressive sperm motility. Three different mixtures of supplements were also tested for their combined effects on sperm motility and reactive oxygen species (ROS) production. While the total motility in the control group was 71.96%, this was found to increase to 82.85% in the first mixture. In contrast the average ROS level was 8.97% in the control group and decreased to 4.23% in the first mixture. Inclusion of a supplement cocktail (5-HT, Se, Zn, vitamins D and E) in sperm processing and culture medium could create an overall improvement in sperm motility while decreasing ROS levels during the incubation period. These molecules may enhance the success of assisted reproduction techniques when present in sperm preparation medium.

Assuntos

Espécies Reativas de Oxigênio , Selênio , Serotonina , Motilidade dos Espermatozoides , Espermatozoides , Vitamina D , Vitamina E , Zinco , Motilidade dos Espermatozoides/efeitos dos fármacos , Masculino , Humanos , Serotonina/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Zinco/farmacologia , Zinco/administração & dosagem , Selênio/farmacologia , Selênio/administração & dosagem , Vitamina E/farmacologia , Espermatozoides/efeitos dos fármacos , Espermatozoides/fisiologia , Espermatozoides/metabolismo , Vitamina D/farmacologia , Suplementos Nutricionais , Adulto

RESUMO

Serotonin (5-HT) imbalances in the developing prefrontal cortex (PFC) are linked to long-term behavioral deficits. However, the synaptic mechanisms underlying 5-HT-mediated PFC development are unknown. We found that chemogenetic suppression and enhancement of 5-HT release in the PFC during the first two postnatal weeks decreased and increased the density and strength of excitatory spine synapses, respectively, on prefrontal layer 2/3 pyramidal neurons in mice. 5-HT release on single spines induced structural and functional long-term potentiation (LTP), requiring both 5-HT2A and 5-HT7 receptor signals, in a glutamatergic activity-independent manner. Notably, LTP-inducing 5-HT stimuli increased the long-term survival of newly formed spines ( ≥ 6 h) via 5-HT7 Gαs activation. Chronic treatment of mice with fluoxetine, a selective serotonin-reuptake inhibitor, during the first two weeks, but not the third week of postnatal development, increased the density and strength of excitatory synapses. The effect of fluoxetine on PFC synaptic alterations in vivo was abolished by 5-HT2A and 5-HT7 receptor antagonists. Our data describe a molecular basis of 5-HT-dependent excitatory synaptic plasticity at the level of single spines in the PFC during early postnatal development.

Assuntos

Fluoxetina , Serotonina , Camundongos , Animais , Serotonina/farmacologia , Fluoxetina/farmacologia , Células Piramidais/fisiologia , Córtex Pré-Frontal/fisiologia , Sinapses/fisiologia

RESUMO

Rapid adenosine transiently regulates dopamine and glutamate via A1 receptors, but other neurotransmitters, such as serotonin, have not been studied. In this study, we examined the rapid modulatory effect of adenosine on serotonin release in the dorsal raphe nuclei (DRN) of mouse brain slices by using fast-scan cyclic voltammetry. To mimic adenosine release during damage, a rapid microinjection of adenosine at 50 pmol was applied before electrical stimulation of serotonin release. Transient adenosine significantly reduced electrically evoked serotonin release in the first 20 s after application, but serotonin release recovered to baseline as adenosine was cleared from the slice. The continuous perfusion of adenosine did not change the evoked serotonin release. Surprisingly, the modulatory effects of adenosine were not regulated by A1 receptors as adenosine still inhibited serotonin release in A1KO mice and also after perfusion of an A1 antagonist (8-cyclopentyl-1,3-dipropyl xanthine). The inhibition was also not regulated by A3 receptors as perfusion of the A3 antagonist (MRS 1220) in A1KO brain slices did not eliminate the inhibitory effects of transient adenosine. In addition, adenosine also inhibited serotonin release in A2AKO mice, showing that A2A did not modulate serotonin. However, perfusion of a selective 5HT1A autoreceptor antagonist drug [(S)-WAY 100135 dihydrochloride] abolished the inhibitory effect of transient adenosine on serotonin release. Thus, the transient neuromodulatory effect of adenosine on DRN serotonin release is regulated by serotonin autoreceptors and not by adenosine receptors. Rapid, transient adenosine modulation of neurotransmitters such as serotonin may have important implications for diseases such as depression and brain injury.

Assuntos

Núcleo Dorsal da Rafe , Serotonina , Camundongos , Animais , Serotonina/farmacologia , Adenosina , Antagonistas da Serotonina/farmacologia , Receptores de Serotonina/fisiologia