ABSTRACT
Genetic variation of the serotonin transporter gene (SLC6A4) has been suggested as potential mediator for antidepressant response in patients with depression. This study aimed to determine whether DNA methylation in SLC6A4 changes after antidepressant treatment and whether it affects treatment response in patients with depression. Overall, 221 Korean patients with depression completed 6 weeks of selective serotonin reuptake inhibitor (SSRI) monotherapy. DNA was extracted from venous blood pre- and post-treatment, and DNA methylation was analyzed using polymerase chain reaction. We used Wilcoxon's signed-rank test to verify the difference in methylation after treatment. Treatment response was assessed using the 17-item Hamilton Depression Rating Scale, and mRNA levels were quantified. After adjusting for relevant covariates, DNA methylation was significantly altered in specific CpG sites in SLC6A4 (p < .001 in CpG3, CpG4, and CpG5) following 6 weeks of treatment. Methylation change's magnitude (ΔDNA methylation) after drug treatment was not associated with treatment response or mRNA level change. SSRI antidepressants can influence SLC6A4 methylation in patients with depression. However, ΔDNA methylation at CpG3, CpG4, and CpG5 in SLC6A4 was not associated with treatment response. Future studies should investigate the integrative effect of other genetic variants and CpG methylation on gene transcription and antidepressant treatment response.
Subject(s)
DNA Methylation , Depressive Disorder, Major , Serotonin Plasma Membrane Transport Proteins , Humans , Antidepressive Agents/pharmacology , Antidepressive Agents/therapeutic use , Depressive Disorder, Major/drug therapy , Depressive Disorder, Major/genetics , DNA Methylation/drug effects , DNA Methylation/genetics , RNA, Messenger/genetics , Selective Serotonin Reuptake Inhibitors/pharmacology , Selective Serotonin Reuptake Inhibitors/therapeutic use , Serotonin Plasma Membrane Transport Proteins/drug effects , Serotonin Plasma Membrane Transport Proteins/geneticsABSTRACT
Depression associated with poor general medical condition, such as post-stroke (PSD) or post-myocardial infarction (PMID) depression, is characterized by resistance to classical antidepressants. Special treatment strategies should thus be developed for these conditions. Our study aims to investigate the mechanism of action of 2-morpholino-5-phenyl-6H-1,3,4-thiadiazine, hydrobromide (L-17), a recently designed thiadiazine derivative with putative neuro- and cardioprotective and antidepressant-like effects, using combined in silico (for prediction of the molecular binding mechanisms), ex vivo (for assessment of the neural excitability using c-Fos immunocytochemistry), and in vivo (for direct examination of the neuronal excitability) methodological approaches. We found that the predicted binding affinities of L-17 to serotonin (5-HT) transporter (SERT) and 5-HT3 and 5-HT1A receptors are compatible with selective 5-HT serotonin reuptake inhibitors (SSRIs) and antagonists of 5-HT3 and 5-HT1A receptors, respectively. L-17 robustly increased c-Fos immunoreactivity in the amygdala and decreased it in the hippocampus. L-17 dose-dependently inhibited 5-HT neurons of the dorsal raphe nucleus; this inhibition was partially reversed by the 5-HT1A antagonist WAY100135. We suggest that L-17 is a potent 5-HT reuptake inhibitor and partial antagonist of 5-HT3 and 5-HT1A receptors; the effects of L-17 on amygdaloid and hippocampal excitability might be mediated via 5-HT, and putatively mediate the antidepressant-like effects of this drug. Since L-17 also possesses neuro- and cardioprotective properties, it can be beneficial in PSD and PMID. Combined in silico predictions with ex vivo neurochemical and in vivo electrophysiological assessments might be a useful strategy for early assessment of the efficacy and neural mechanism of action of novel CNS drugs.
Subject(s)
Antidepressive Agents/pharmacology , Depression/drug therapy , Hydrazines/pharmacology , Myocardial Infarction/complications , Stroke/complications , Animals , Antidepressive Agents/therapeutic use , Computer Simulation , Depression/etiology , Hippocampus/drug effects , Hippocampus/metabolism , Hydrazines/therapeutic use , Male , Neurons/drug effects , Neurons/metabolism , Neuroprotective Agents/pharmacology , Neuroprotective Agents/therapeutic use , Protective Agents/pharmacology , Protective Agents/therapeutic use , Rats , Rats, Wistar , Receptor, Serotonin, 5-HT1A/drug effects , Receptors, Serotonin, 5-HT3/drug effects , Serotonin 5-HT1 Receptor Antagonists , Serotonin 5-HT3 Receptor Antagonists , Serotonin Plasma Membrane Transport Proteins/drug effects , Selective Serotonin Reuptake Inhibitors/pharmacologyABSTRACT
Clandestine chemists are currently exploiting the pyrrolidinophenone scaffold to develop new designer drugs that carry the risk of abuse and overdose. These drugs promote addiction through the rewarding effects of increased dopaminergic neurotransmission. 3,4-Methylenedioxypyrovalerone (MDPV) and its analogs are illicit psychostimulants of this class that are â¼50-fold more potent than cocaine at inhibiting the human dopamine transporter (hDAT). In contrast, MDPV is a weak inhibitor at both the human serotonin transporter (hSERT) and, as it is shown here, the Drosophila melanogaster DAT (dDAT). We studied three conserved residues between hSERT and dDAT that are unique in hDAT (A117, F318, and P323 in dDAT), and one residue that is different in all three transporters (D121 in dDAT). hDAT residues were replaced in the dDAT sequence at these positions using site-directed mutagenesis and stable cell lines were generated expressing these mutant transporters. The potencies of MDPV and two of its analogs were determined using a Ca2+-mobilization assay. In this assay, voltage-gated Ca2+ channels are expressed to sense the membrane electrical depolarization evoked when dopamine is transported through DAT. Each individual mutant slightly improved MDPV's potency, but the combination of all four increased its potency â¼100-fold (2 log units) in inhibiting dDAT activity. Molecular modeling and docking studies were conducted to explore the possible mode of interaction between MDPV and DAT in silico. Two of the studied residues (F318 and P323) are at the entrance of the S1 binding site, whereas the other two (A117 and D121) face the aryl moiety of MDPV when bound to this site. Therefore, these four non-conserved residues can influence MDPV selectivity not only by stabilizing binding, but also by controlling access to its binding site at DAT.
Subject(s)
Benzodioxoles/pharmacology , Designer Drugs/chemistry , Designer Drugs/pharmacology , Dopamine Plasma Membrane Transport Proteins/drug effects , Pyrrolidines/pharmacology , Serotonin Plasma Membrane Transport Proteins/drug effects , Animals , Benzodioxoles/chemistry , Biological Transport/drug effects , Calcium Channels/drug effects , Cell Line , Dopamine Uptake Inhibitors/pharmacology , Drosophila melanogaster , Molecular Docking Simulation , Pyrrolidines/chemistry , Synthetic CathinoneABSTRACT
The serotonin transporter (SERT) shapes serotonergic neurotransmission by retrieving its eponymous substrate from the synaptic cleft. Ligands that discriminate between SERT and its close relative, the dopamine transporter DAT, differ in their association rate constant rather than their dissociation rate. The structural basis for this phenomenon is not known. Here we examined the hypothesis that the extracellular loops 2 (EL2) and 4 (EL4) limit access to the ligand-binding site of SERT. We employed an antibody directed against EL4 (residues 388-400) and the antibody fragments 8B6 scFv (directed against EL2 and EL4) and 15B8 Fab (directed against EL2) and analyzed their effects on the transport cycle of and inhibitor binding to SERT. Electrophysiological recordings showed that the EL4 antibody and 8B6 scFv impeded the initial substrate-induced transition from the outward to the inward-facing conformation but not the forward cycling mode of SERT. In contrast, binding of radiolabeled inhibitors to SERT was enhanced by either EL4- or EL2-directed antibodies. We confirmed this observation by determining the association and dissociation rate of the DAT-selective inhibitor methylphenidate via electrophysiological recordings; occupancy of EL2 with 15B8 Fab enhanced the affinity of SERT for methylphenidate by accelerating its binding. Based on these observations, we conclude that (i) EL4 undergoes a major movement during the transition from the outward to the inward-facing state, and (ii) EL2 and EL4 limit access of inhibitors to the binding of SERT, thus acting as a selectivity filter. This insight has repercussions for drug development.
Subject(s)
Dopamine Plasma Membrane Transport Proteins/genetics , Membrane Transport Proteins/genetics , Protein Conformation/drug effects , Selective Serotonin Reuptake Inhibitors/pharmacology , Serotonin Plasma Membrane Transport Proteins/genetics , Amino Acid Sequence/genetics , Animals , Binding Sites/drug effects , COS Cells , Chlorocebus aethiops , Dopamine Plasma Membrane Transport Proteins/antagonists & inhibitors , Dopamine Plasma Membrane Transport Proteins/ultrastructure , HEK293 Cells , Humans , Ligands , Membrane Transport Proteins/chemistry , Membrane Transport Proteins/ultrastructure , Patch-Clamp Techniques , Protein Domains/genetics , Serotonin/chemistry , Serotonin/genetics , Serotonin Plasma Membrane Transport Proteins/drug effects , Serotonin Plasma Membrane Transport Proteins/ultrastructure , Selective Serotonin Reuptake Inhibitors/chemistryABSTRACT
BACKGROUND: Dopamine transporter (DAT) and serotonin transporter (SERT) are targets for many psychoactive substances. Functional assays including uptake inhibition and release assays often involve radiolabeled compounds like [3H]-dopamine and [3H]-serotonin to assess drug activity at transporters, which have high requirements on handling radioactive samples. AIMS: The aim of this study was to establish a label-free method to assess drug activity at DAT and SERT. METHODS: A liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method was established using transporter-transfected human embryonic kidney 293T (HEK293T) cells. This method was evaluated by testing the effects of amphetamine and cocaine in the assay procedure. RESULTS: The limits of detection of this method were 0.2 nM for both dopamine (DA) and serotonin (5-HT), with good linearities in the range of 0.5-160 nM. Amphetamine and cocaine's IC50 and EC50 on DAT and SERT determined by this method were consistent with previous reports. CONCLUSIONS: A rapid, reliable and label-free LC-MS/MS method for assessing drug activity was established, which affords an attractive alternative for those laboratories that do not have a radiation license or capabilities.
Subject(s)
Chromatography, Liquid/methods , Dopamine Plasma Membrane Transport Proteins/drug effects , Serotonin Plasma Membrane Transport Proteins/drug effects , Tandem Mass Spectrometry/methods , Amphetamine/administration & dosage , Amphetamine/pharmacology , Cocaine/administration & dosage , Cocaine/pharmacology , Dopamine/metabolism , Dopamine Plasma Membrane Transport Proteins/metabolism , Dopamine Uptake Inhibitors/administration & dosage , Dopamine Uptake Inhibitors/pharmacology , Dose-Response Relationship, Drug , HEK293 Cells , Humans , Reproducibility of Results , Serotonin/metabolism , Serotonin Plasma Membrane Transport Proteins/metabolismABSTRACT
While classical cathinones, such as methcathinone, have been shown to be monoamine releasing agents at human monoamine transporters, the subgroup of α-pyrrolidinophenones has thus far solely been characterized as monoamine transporter reuptake inhibitors. Herein, we report data from previously undescribed α-pyrrolidinopropiophenone (α-PPP) derivatives and compare them with the pharmacologically well-researched α-PVP (α-pyrrolidinovalerophenone). Radiotracer-based in vitro uptake inhibition assays in HEK293 cells show that the investigated α-PPP derivatives inhibit the human high-affinity transporters of dopamine (hDAT) and norepinephrine (hNET) in the low micromolar range, with α-PVP being ten times more potent. Similar to α-PVP, no relevant pharmacological activity was found at the human serotonin transporter (hSERT). Unexpectedly, radiotracer-based in vitro release assays reveal α-PPP, MDPPP and 3Br-PPP, but not α-PVP, to be partial releasing agents at hNET (EC50 values in the low micromolar range). Furthermore, uptake inhibition assays at low-affinity monoamine transporters, i.e., the human organic cation transporters (hOCT) 1-3 and human plasma membrane monoamine transporter (hPMAT), bring to light that all compounds inhibit hOCT1 and 2 (IC50 values in the low micromolar range) while less potently interacting with hPMAT and hOCT3. In conclusion, this study describes (i) three new hybrid compounds that efficaciously block hDAT while being partial releasers at hNET, and (ii) highlights the interactions of α-PPP-derivatives with low-affinity monoamine transporters, giving impetus to further studies investigating the interaction of drugs of abuse with OCT1-3 and PMAT.
Subject(s)
Norepinephrine Plasma Membrane Transport Proteins/drug effects , Norepinephrine/metabolism , Propiophenones/pharmacology , Pyrroles/pharmacology , Pyrrolidines/pharmacology , Dopamine Plasma Membrane Transport Proteins/drug effects , Dopamine Plasma Membrane Transport Proteins/metabolism , Equilibrative Nucleoside Transport Proteins/drug effects , Equilibrative Nucleoside Transport Proteins/metabolism , HEK293 Cells , Humans , In Vitro Techniques , Norepinephrine Plasma Membrane Transport Proteins/metabolism , Organic Cation Transport Proteins/drug effects , Organic Cation Transport Proteins/metabolism , Organic Cation Transporter 1/drug effects , Organic Cation Transporter 1/metabolism , Organic Cation Transporter 2/drug effects , Organic Cation Transporter 2/metabolism , Serotonin Plasma Membrane Transport Proteins/drug effects , Serotonin Plasma Membrane Transport Proteins/metabolismABSTRACT
The early characterization of ligands at the dopamine and serotonin transporters, DAT and SERT, respectively, is important for drug discovery, forensic sciences, and drug abuse research. 4-Methyl amphetamine (4-MA) is a good example of an abused drug whose overdose can be fatal. It is a potent substrate at DAT and SERT where its simplest secondary amine (N-methyl 4-MA) retains substrate activity at them. In contrast, N-n-butyl 4-MA is very weak, therefore it was categorized as inactive at these transporters. Here, N-octyl 4-MA and other related compounds were synthesized, and their activities were evaluated at DAT and SERT. To expedite this endeavor, cells expressing DAT or SERT were co-transfected with a voltage-gated Ca2+ channel and, the genetically-encoded Ca2+ sensor, GCaMP6s. Control compounds and the newly synthesized molecules were tested on these cells using an automated multi-well fluorescence plate reader; substrates and inhibitors were identified successfully at DAT and SERT. N-Octyl 4-MA and three bivalent compounds were inhibitors at these transporters. These findings were validated by measuring Ca2+-mobilization using quantitative fluorescence microscopy. The bivalent molecules were the most potent of the series and were further characterized in an uptake-inhibition assay. Compared to cocaine, they showed comparable potency inhibiting uptake at DAT and higher potency at SERT. These observations support a previous hypothesis that amphetamine-related (and, here, N-extended alkyl and) bivalent arylalkylamine molecules are active at monoamine transporters, showing potent activity as reuptake inhibitors, and implicate the involvement of a distant auxiliary binding feature to account for their actions at DAT and SERT.
Subject(s)
Biosensing Techniques , Calcium Channels/metabolism , Calcium/metabolism , Dopamine Plasma Membrane Transport Proteins/antagonists & inhibitors , Dopamine Uptake Inhibitors/toxicity , Green Fluorescent Proteins/metabolism , Methamphetamine/toxicity , Selective Serotonin Reuptake Inhibitors/toxicity , Serotonin Plasma Membrane Transport Proteins/drug effects , Calcium Channels/genetics , Dopamine Plasma Membrane Transport Proteins/genetics , Dopamine Plasma Membrane Transport Proteins/metabolism , Green Fluorescent Proteins/genetics , HEK293 Cells , Humans , Methamphetamine/analogs & derivatives , Methamphetamine/chemical synthesis , Microscopy, Fluorescence , Molecular Structure , Serotonin Plasma Membrane Transport Proteins/genetics , Serotonin Plasma Membrane Transport Proteins/metabolism , Structure-Activity Relationship , Time FactorsABSTRACT
AIMS: 5-Methoxy-N,N-diisopropyltryptamine (5-MeO-DIPT) is a synthetic orally active hallucinogenic tryptamine analogue. The present study examined whether the effects of 5-MeO-DIPT involve the serotonin transporter (SERT) and serotonin 5-hydroxytryptamine-1A (5-HT1A ) receptor in the striatum and prefrontal cortex (PFC). METHODS: We investigated the effects of 5-MeO-DIPT on extracellular 5-HT (5-HTex ) and dopamine (DAex ) levels in the striatum and PFC in wildtype and SERT knockout (KO) mice using in vivo microdialysis, and for comparison the effects of the 5-HT1A receptor antagonist WAY100635 and the 5-HT1A receptor agonist 8-OH-DPAT on 5-HTex . RESULTS: 5-MeO-DIPT decreased 5-HTex levels in the striatum, but not PFC. In SERT-KO mice, 5-MeO-DIPT did not affect 5-HTex levels in the striatum or PFC. In the presence of WAY100635, 5-MeO-DIPT substantially increased 5-HTex levels, suggesting that 5-MeO-DIPT acts on SERT and these effects are masked by its 5-HT1A actions in the absence of WAY100635. 8-OH-DPAT decreased 5-HTex levels in the striatum and PFC in wildtype mice. WAY100635 antagonized the 8-OH-DPAT-induced decrease in 5-HTex levels. In SERT-KO mice, 8-OH-DPAT did not decrease 5-HTex levels in the striatum and PFC. 5-MeO-DIPT dose-dependently increased DAex levels in the PFC, but not striatum, in wildtype and SERT-KO mice. The increase in DAex levels that was induced by 5-MeO-DIPT was not antagonized by WAY100635. CONCLUSION: 5-MeO-DIPT influences both 5-HTex and DAex levels in the striatum and PFC. 5-MeO-DIPT dually acts on SERT and 5-HT1A receptors so that elevations in 5-HTex levels produced by reuptake inhibition are limited by actions of the drug on 5-HT1A receptors.
Subject(s)
5-Methoxytryptamine/analogs & derivatives , Corpus Striatum/drug effects , Prefrontal Cortex/drug effects , Receptor, Serotonin, 5-HT1A/drug effects , Serotonin 5-HT1 Receptor Agonists/pharmacology , Serotonin 5-HT1 Receptor Antagonists/pharmacology , Serotonin Plasma Membrane Transport Proteins/drug effects , 5-Methoxytryptamine/pharmacology , 8-Hydroxy-2-(di-n-propylamino)tetralin/pharmacology , Animals , Corpus Striatum/metabolism , Female , Male , Mice , Mice, Knockout , Microdialysis , Piperazines/pharmacology , Prefrontal Cortex/metabolism , Pyridines/pharmacology , Receptor, Serotonin, 5-HT1A/metabolism , Serotonin Plasma Membrane Transport Proteins/metabolismABSTRACT
Vulnerability to drug addiction relies on substantial individual differences. We previously demonstrated that serotonin transporter knockout (SERT-/- ) rats show increased cocaine intake and develop signs of compulsivity. However, the underlying neural mechanisms are not fully understood. Given the pivotal role of glutamate and prefrontal cortex in cocaine-seeking behavior, we sought to investigate the expression of proteins implicated in glutamate neurotransmission in the prefrontal cortex of naïve and cocaine-exposed rats lacking SERT. We focused on the infralimbic (ILc) and prelimbic (PLc) cortices, which are theorized to exert opposing effects on the control over subcortical brain areas. SERT-/- rats, which compared to wild-type (SERT+/+ ) rats show increased ShA and LgA intake short-access (ShA) and long-access (LgA) cocaine intake, were sacrificed 24 h into withdrawal for ex vivo molecular analyses. In the ILc homogenate of SERT-/- rats, we observed a sharp increase in glial glutamate transporter 1 (GLT-1) after ShA, but not LgA, cocaine intake. This was paralleled by ShA-induced increases in GluN1, GluN2A, and GluN2B NMDA receptor subunits and their scaffolding protein SAP102 in the ILc homogenate, but not postsynaptic density, of these knockout animals. In the PLc, we found no major changes in the homogenate; conversely, the expression of GluN1 and GluN2A NMDA receptor subunits was increased in the postsynaptic density under ShA conditions and reduced under LgA conditions. These results point to SERT as a critical regulator of glutamate homeostasis in a way that differs between the subregions investigated, the duration of cocaine exposure as well as the cellular compartment analyzed.
Subject(s)
Cocaine/pharmacology , Glutamic Acid/drug effects , Prefrontal Cortex/drug effects , Serotonin Plasma Membrane Transport Proteins/drug effects , Animals , Male , Rats , Synaptic Transmission/drug effectsABSTRACT
Fluoxetine is one of SSRIs commonly used as first-line antidepressants. It also induces adverse effects, including bleeding events. This study clarified the bleeding effect of fluoxetine and explored the action cascade of this drug leading to a longer bleeding time. A total of 48 male adult mice were evenly distributed into four groups and given fluoxetine in saline at 0, 4, 8, or 16 mg/kg, for 14 days. On day 15, tail bleeding time of 6 mice/group was measured, and their blood samples were collected for analyses of relevant platelet functions. The remained mice were allowed to survive for another 14 days without fluoxetine, and subjected to the same analyses on day 29. A significant effect of fluoxetine was reveled on bleeding time (F (3,20) = 16.842, P < 0.01) and intraplatelet serotonin (F (3,20) = 90.967, P < 0.01). Moreover, fluoxetine effectively inhibited platelet aggregation (F(3, 20) = 30.247, P < 0.01), decreased amount of GPIbα (F(3, 20) = 23.855, P < 0.01), suppressed GPIIb/IIIa activation (F(3, 20) = 89.441, P < 0.01), and lowered P-selectin (F(3, 20) = 7.960, P < 0.01) on platelet surface. Negative correlations existed between bleeding time and the aforementioned four indices, whereas correlations between intraplatelet serotonin and the same indices were positive. All changes returned to same levels as Control group after fluoxetine withdrawal. These data suggest an action pathway of fluoxetine starting at binding to serotonin transporter, followed by decreased intraplatelet serotonin, increased GPIbα shedding, suppressed GPIIb/IIIa activation, and inhibited α-granule release, and concluding with prolonged bleeding time in mice.
Subject(s)
Antidepressive Agents, Second-Generation/toxicity , Blood Platelets/drug effects , Fluoxetine/toxicity , Platelet Activation/drug effects , Selective Serotonin Reuptake Inhibitors/toxicity , Animals , Bleeding Time , Blood Platelets/metabolism , Cytoplasmic Granules/drug effects , Cytoplasmic Granules/metabolism , Male , Mice, Inbred ICR , Platelet Aggregation/drug effects , Platelet Glycoprotein GPIIb-IIIa Complex/metabolism , Platelet Glycoprotein GPIb-IX Complex/metabolism , Serotonin/blood , Serotonin Plasma Membrane Transport Proteins/blood , Serotonin Plasma Membrane Transport Proteins/drug effects , Time FactorsABSTRACT
Lumateperone (ITI-007) is a tosylate salt with binding affinities to receptors implicated in the therapeutic actions of antipsychotic medications, including the serotonin 5HT2A receptors, dopamine D2 and D1 receptors and the serotonin transporter. It has a unique mechanism of action because it simultaneously modulates serotonin, dopamine, and glutamate neurotransmission, implicated in serious mental illness. It can be considered a multi-target-directed ligand and a multifunctional modulator of serotoninergic system with possible precognitive, antipsychotic, antidepressant and anxiolytic properties. Lumateperone has been investigated as a novel agent for the treatment of schizophrenia, but it represents a new potential option for other psychiatric and neurological diseases, such as behavioural symptoms of dementia or Alzheimer's disease, sleep disturbances, bipolar depression. Besides, it has demonstrated a favourable safety profile without significant extrapyramidal side effects, hyperprolactinemia or changes in cardiometabolic or endocrine factors versus placebo. Additional studies are warranted to confirm and examine the benefit of lumateperone and possible therapeutic targets. This paper is a comprehensive and thorough summary of the most important findings and potential future role of this particular compound in personalized treatments.
Subject(s)
Alzheimer Disease/drug therapy , Dopamine D2 Receptor Antagonists/therapeutic use , Heterocyclic Compounds, 4 or More Rings/therapeutic use , Schizophrenia/drug therapy , Serotonin 5-HT2 Receptor Antagonists/therapeutic use , Sleep Wake Disorders/drug therapy , Alzheimer Disease/psychology , Bipolar Disorder/drug therapy , Dementia/drug therapy , Dementia/psychology , Dopamine D2 Receptor Antagonists/pharmacology , Drug Partial Agonism , Heterocyclic Compounds, 4 or More Rings/pharmacology , Humans , Receptor, Serotonin, 5-HT2A/drug effects , Receptors, Dopamine D1/drug effects , Receptors, Dopamine D2/drug effects , Serotonin 5-HT2 Receptor Antagonists/pharmacology , Serotonin Plasma Membrane Transport Proteins/drug effectsABSTRACT
Many women diagnosed with a major depression continue or initiate antidepressant treatment during pregnancy. Both maternal stress and selective serotonin inhibitor (SSRI) antidepressant treatment during pregnancy have been associated with changes in offspring behavior, including increased anxiety and depressive-like behavior. Our aim was to investigate the effects of the SSRI fluoxetine (FLX), with and without the presence of a maternal depression, on affective behavior in male and female rat offspring. As reduced serotonin transporter (SERT) availability has been associated with altered behavioral outcome, both offspring with normal (SERT+/+) and reduced (SERT+/-) SERT expression were included. For our animal model of maternal depression, SERT+/- dams exposed to early life stress were used. Perinatal FLX treatment and early life stress in dams (ELSD) had sex- and genotype-specific effects on affective behavior in the offspring. In female offspring, perinatal FLX exposure interacted with SERT genotype to increase anxiety and depressive-like behavior in SERT+/+, but not SERT+/-, females. In male offspring, ELSD reduced anxiety and interacted with SERT genotype to decrease depressive-like behavior in SERT+/-, but not SERT+/+, males. Altogether, SERT+/+ female offspring appear to be more sensitive than SERT+/- females to the effects of perinatal FLX exposure, while SERT+/- male offspring appear more sensitive than SERT+/+ males to the effects of ELSD on affective behavior. Our data suggest a role for offspring SERT genotype and sex in FLX and ELSD-induced effects on affective behavior, thereby contributing to our understanding of the effects of perinatal SSRI treatment on offspring behavior later in life.
Subject(s)
Affect , Fluoxetine , Serotonin Plasma Membrane Transport Proteins , Stress, Psychological , Animals , Female , Male , Pregnancy , Rats , Affect/drug effects , Animals, Newborn , Antidepressive Agents/pharmacology , Anxiety , Anxiety Disorders/drug therapy , Behavior, Animal/drug effects , Depression , Depressive Disorder/drug therapy , Disease Models, Animal , Fluoxetine/pharmacology , Genotype , Maternal Behavior/drug effects , Prenatal Exposure Delayed Effects/drug therapy , Rats, Wistar , RNA-Binding Proteins/genetics , RNA-Binding Proteins/metabolism , Selective Serotonin Reuptake Inhibitors/pharmacology , Serotonin Plasma Membrane Transport Proteins/drug effects , Serotonin Plasma Membrane Transport Proteins/genetics , Sex FactorsABSTRACT
This study is to investigate the effect of Paeonia lactiflora extract on PMS anxiety and on expression of estrogen receptor ß (ERß), tryptophan hydroxylase-2 (TPH2), and serotonin transporter (SERT) in the premenstrual syndrome (PMS) anxiety model rats. The vaginal smear and open field test were used to screen rats in nonreception phase of estrus cycle with similar macroscopic behaviors and regular estrus cycle. PMS anxiety model rats were prepared by electrical stimulation. RT-PCR and immunofluorescence were used to measure the expression of ERß, TPH2, and SERT. Compared with normal rats, the total distance in the open field test of the model rats was significantly increased (P < 0.05). The model rats showed nervous alertness, irritability, and sensitivity to external stimuli. After treatment with the Paeonia lactiflora extract, the total distance of rats was significantly reduced (P < 0.05). In reception stage, there was no significant difference in the mRNA and protein expression of ERß, TPH2, and SERT. In nonreception stage, the expression of ERß and TPH2 in the model group was significantly decreased (P < 0.05) as compared with the control group, but not SERT. Abnormal changes of the above indicators were reversed after the administration of the Paeonia lactiflora extract. In conclusion, Paeonia lactiflora extract can increase the expression of ERß and TPH2 and decrease SERT in PMS model rats, which may be one of the mechanisms underlying the effect of Paeonia lactiflora extract on PMS.
Subject(s)
Anxiety/complications , Estrogen Receptor beta/drug effects , Paeonia/chemistry , Plant Extracts/pharmacology , Premenstrual Syndrome/complications , Serotonin Plasma Membrane Transport Proteins/drug effects , Tryptophan Hydroxylase/drug effects , Animals , Anxiety/metabolism , Anxiety Disorders/complications , Anxiety Disorders/metabolism , Disease Models, Animal , Estrogen Receptor beta/metabolism , Female , Male , Rats , Rats, Wistar , Serotonin Plasma Membrane Transport Proteins/metabolism , Tryptophan Hydroxylase/metabolismABSTRACT
Two decades ago, the observation of a rapid and sustained antidepressant response after ketamine administration provided an exciting new avenue in the search for more effective therapeutics for the treatment of clinical depression. Research elucidating the mechanism(s) underlying ketamine's antidepressant properties has led to the development of several hypotheses, including that of disinhibition of excitatory glutamate neurons via blockade of N-methyl-d-aspartate (NMDA) receptors. Although the prominent understanding has been that ketamine's mode of action is mediated solely via the NMDA receptor, this view has been challenged by reports implicating other glutamate receptors such as AMPA, and other neurotransmitter systems such as serotonin and opioids in the antidepressant response. The recent approval of esketamine (Spravato™) for the treatment of depression has sparked a resurgence of interest for a deeper understanding of the mechanism(s) underlying ketamine's actions and safe therapeutic use. This review aims to present our current knowledge on both NMDA and non-NMDA mechanisms implicated in ketamine's response, and addresses the controversy surrounding the antidepressant role and potency of its stereoisomers and metabolites. There is much that remains to be known about our understanding of ketamine's antidepressant properties; and although the arrival of esketamine has been received with great enthusiasm, it is now more important than ever that its mechanisms of action be fully delineated, and both the short- and long-term neurobiological/functional consequences of its treatment be thoroughly characterized.
Subject(s)
Antidepressive Agents/therapeutic use , Depressive Disorder, Major/drug therapy , Depressive Disorder, Treatment-Resistant/drug therapy , Ketamine/therapeutic use , Antidepressive Agents/pharmacology , Dopamine Plasma Membrane Transport Proteins/drug effects , Excitatory Amino Acid Antagonists/pharmacology , Excitatory Amino Acid Antagonists/therapeutic use , Humans , Ketamine/pharmacology , Norepinephrine Plasma Membrane Transport Proteins/drug effects , Receptor, Muscarinic M1/drug effects , Receptors, AMPA/drug effects , Receptors, Dopamine D2/drug effects , Receptors, N-Methyl-D-Aspartate/drug effects , Receptors, Opioid, delta/drug effects , Receptors, Opioid, kappa/drug effects , Receptors, Opioid, mu/drug effects , Receptors, Serotonin, 5-HT3/drug effects , Receptors, sigma/drug effects , Serotonin Plasma Membrane Transport Proteins/drug effectsABSTRACT
Despite recent advances, current antidepressants have considerable limitations: late onset of action and the high profile of refractoriness. Biomedical research with natural products has gained growing interest in the last years, and had provide useful candidates for new antidepressants. Riparins are a group of natural alkamides obtained from Aniba riparia, which had marked neuroactive effects, mainly as antidepressant and antinociceptive agents. We made modifications of the basic structure of riparins, originating a synthetic alkamide, also known as riparin IV (RipIV). RipIV demonstrated a superior analgesic effect than its congeners and a marked antidepressant-like effect. However, the basic mechanism for the central effects of RipIV remains unknown. Here, we aimed to investigate the participation of monoaminergic neurotransmission targets in the antidepressant-like effects of RipIV. To do this, we applied a combined approach of experimental (classical pharmacology and neurochemistry) and computer-aided techniques. Our results demonstrated that RipIV presented antidepressant- and anxiolytic-like effects without modifying locomotion and motor coordination of mice. Also, RipIV increased brain monoamines and their metabolite levels. At the higher dose (100â¯mg/kg), RipIV increased serotonin concentrations in all studied brain areas, while at the lower one (50â¯mg/kg), it increased mainly dopamine and noradrenaline levels. When tested with selective receptor antagonists, RipIV antidepressant effect showed dependence of the activation of multiple targets, including D1 and D2 dopamine receptors, 5-HT2A/2, 5-HT3 receptors and α2 adrenergic receptors. Molecular docking demonstrated favorable binding conformation and affinity of RipIV to monoamine oxidase B (MAO-B), serotonin transporter (SERT), α1 receptor, D2 receptor, dopamine transporter (DAT) and at some extent GABA-A receptor. RipIV also presented a computationally predicted favorable pharmacokinetic profile. Therefore, this study demonstrated the involvement of monoaminergic targets in the mechanism of RipIV antidepressant-like action, and provide evidence of it as a promising new antidepressant.
Subject(s)
Anti-Anxiety Agents/pharmacology , Antidepressive Agents/pharmacology , Monoamine Oxidase/drug effects , Receptors, Adrenergic, alpha-2/drug effects , Receptors, Dopamine/drug effects , Receptors, Serotonin/drug effects , Tyramine/analogs & derivatives , Animals , Brain/drug effects , Brain/metabolism , Bupropion/pharmacology , Dopamine/metabolism , Dopamine Plasma Membrane Transport Proteins/drug effects , Dopamine Plasma Membrane Transport Proteins/metabolism , Fluoxetine/pharmacology , Imipramine/pharmacology , Mice , Molecular Docking Simulation , Monoamine Oxidase/metabolism , Norepinephrine/metabolism , Receptor, Serotonin, 5-HT2A/drug effects , Receptor, Serotonin, 5-HT2A/metabolism , Receptors, Adrenergic, alpha-2/metabolism , Receptors, Dopamine/metabolism , Receptors, Dopamine D1 , Receptors, Dopamine D2 , Receptors, GABA-A/drug effects , Receptors, GABA-A/metabolism , Receptors, Serotonin/metabolism , Receptors, Serotonin, 5-HT2/drug effects , Receptors, Serotonin, 5-HT2/metabolism , Receptors, Serotonin, 5-HT3/drug effects , Receptors, Serotonin, 5-HT3/metabolism , Serotonin/metabolism , Serotonin Plasma Membrane Transport Proteins/drug effects , Serotonin Plasma Membrane Transport Proteins/metabolism , Tyramine/pharmacologyABSTRACT
The aim of this study was to investigate the causal role of an early serotonin injury on parkinsonian-like motor symptomatology. Monkeys were pretreated with 3,4-methylenedioxy-N-methamphetamine (MDMA, or "ecstasy"), known to lesion serotonergic fibers, before being administered 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). We combined behavioural assessment, PET imaging, and immunohistochemistry. Strikingly, prior MDMA administration aggravated MPTP-induced Parkinsonism and associated dopaminergic injury. Monkeys with early MDMA lesions developed parkinsonian deficits more rapidly and more severely. Interestingly, not all symptoms were impacted. Bradykinesia, rigidity and freezing were not affected by early MDMA lesions, whereas spontaneous activities, tremor and abnormal posture were significantly aggravated. Finally, as expected, MDMA induced a decrease of the serotonergic transporter availability. More surprisingly, we found that MDMA evoked also a decreased availability of the dopaminergic transporter to a lesser extent. Altogether, these results show that MDMA administration in non-human primates not only damage serotonergic terminals, but also injure dopaminergic neurons and enhance MPTP neurotoxic action, a completely new result in primates.
Subject(s)
Dopamine Plasma Membrane Transport Proteins/drug effects , Dopaminergic Neurons/drug effects , N-Methyl-3,4-methylenedioxyamphetamine/toxicity , Parkinsonian Disorders , Serotonin Agents/toxicity , Serotonin Plasma Membrane Transport Proteins/drug effects , Animals , Dopamine Plasma Membrane Transport Proteins/metabolism , Dopaminergic Neurons/metabolism , Dopaminergic Neurons/pathology , Macaca fascicularis , Male , Serotonin Plasma Membrane Transport Proteins/metabolismABSTRACT
Neonatal ventral hippocampal-lesioned (NVHL) rats have been shown to display neurochemical and behavioral abnormalities at adulthood, analogous to some of those seen in schizophrenia. Serotonergic neurotransmission is implicated the pathophysiology and treatment of schizophrenia. In this study, we evaluated possible role of serotonergic transmission is the behaviors of NVHL-lesioned rats. Bilateral lesions to the ventral hippocampus (VH) in rat pups were made using the excitotoxin ibotenic acid. We investigated 5-HT2A-receptor and SERT binding sites in cortical and subcortical areas in post-pubertal NVHL and sham-lesioned rats, using quantitative receptor autoradiography. We compared a 5-HT-dependent behavior in NVHL and sham animals, the wet-dog shake response (WDSr) to a 5-HT2A receptor agonist DOI. In addition, we studied prepulse inhibition (PPI) of startle responses in NVHL and Sham-lesioned animals treated with antipsychotic drugs haloperidol, risperidone and clozapine and 5-HT2A antagonists ketanserin or MDL100907. The WDSr elicited by DOI was enhanced in post-pubertal NVHL rats compared to sham-lesioned controls. Moreover, post-pubertal NVHL rats exhibited PPI deficits which was reversed by atypical antipsychotics, ketanserin and MDL100907. A significant increase in 5-HT2A-like receptor binding was observed in the medial prefrontal cortex (mPFC) in post-pubertal NVHL rats without any significant change in the striatum and ventral pallidum. A significant increase in SERT-like binding was also observed in the mPFC and striatum of NVHL rats at pre-pubertal period; however, at post-pubertal age, the binding remained elevated in mPFC only. These data suggest that increased prefrontal cortical 5-HT transmission may play a role in the behavioral deficits observed in this neurodevelopmental model of schizophrenia.
Subject(s)
Antipsychotic Agents/pharmacology , Behavior, Animal/physiology , Hippocampus/pathology , Prefrontal Cortex/metabolism , Prepulse Inhibition/physiology , Receptor, Serotonin, 5-HT2A/metabolism , Schizophrenia , Serotonin 5-HT2 Receptor Agonists/pharmacology , Serotonin 5-HT2 Receptor Antagonists/pharmacology , Serotonin Plasma Membrane Transport Proteins/metabolism , Age Factors , Animals , Animals, Newborn , Autoradiography , Behavior, Animal/drug effects , Disease Models, Animal , Prefrontal Cortex/drug effects , Prepulse Inhibition/drug effects , Rats , Receptor, Serotonin, 5-HT2A/drug effects , Reflex, Startle/drug effects , Reflex, Startle/physiology , Schizophrenia/drug therapy , Schizophrenia/metabolism , Schizophrenia/physiopathology , Serotonin Plasma Membrane Transport Proteins/drug effects , Sexual Maturation/physiologyABSTRACT
BACKGROUND: The potential long-term effects of childhood fluoxetine therapy on brain serotonin systems were studied using a nonhuman primate model, the rhesus monkey. METHODS: Juvenile male rhesus (1-4 years of age, corresponding to 4-11 years of age in children) were treated orally with fluoxetine (2 mg/kg) or vehicle daily for 2 years and removed from treatment during the third year. Each treatment group was assigned an equal number of subjects with low and high transcription polymorphisms of MAOA. One year after discontinuation of treatment, positron emission tomography scans were conducted (n = 8 treated monkeys, n = 8 control monkeys) using [11C]DASB to quantify serotonin transporter in 16 cortical and subcortical regions. RESULTS: Fluoxetine-treated monkeys with MAOA low transcription polymorphism had significantly lower [11C]DASB binding potentials than control monkeys. This finding was seen throughout the brain but was strongest in prefrontal and cingulate cortices. The MAOA × fluoxetine interaction was enhanced by binding potentials that were nonsignificantly higher in monkeys with high transcription polymorphism. CONCLUSIONS: Juvenile fluoxetine treatment has residual posttreatment effects on brain serotonin transporter that depend on MAOA genotype. MAOA genotype may be important to consider when treating children with fluoxetine.
Subject(s)
Brain/drug effects , Fluoxetine/pharmacology , Monoamine Oxidase/genetics , Selective Serotonin Reuptake Inhibitors/pharmacology , Serotonin Plasma Membrane Transport Proteins/drug effects , Age Factors , Aniline Compounds/pharmacokinetics , Animals , Brain/diagnostic imaging , Female , Fluoxetine/administration & dosage , Gyrus Cinguli/diagnostic imaging , Gyrus Cinguli/drug effects , Macaca mulatta , Male , Positron-Emission Tomography , Prefrontal Cortex/diagnostic imaging , Prefrontal Cortex/drug effects , Protein Binding , Selective Serotonin Reuptake Inhibitors/administration & dosage , Sulfides/pharmacokinetics , Time FactorsABSTRACT
Major depression and anxiety are highly incapacitating psychiatric disorders often present simultaneously, and the causal relationship between these disorders and inflammation are under extensive investigation. The treatment for this comorbidity still relies on drugs acting on the serotonergic neurotransmission, but the modulation of immune-inflammatory pathways has attained an increasing interest in the drug discovery. We have previously demonstrated that the selenoorganic compound 3-[(4-chlorophenyl)selanyl]-1-methyl-1H-indole (CMI) possess antioxidant, anti-inflammatory, antinociceptive and antidepressant-like effect in mice. Considering these pharmacological properties and the structural similarities between tryptophan, serotonin and CMI, the aim of the present study was to investigate whether CMI ameliorates depression- and anxiogenic-like behavior induced by lipopolysaccharide (LPS) in Swiss male mice by modulating the serotonergic system and reducing neuroinflammation. The administration of CMI (1â¯mg/kg, i.g) reversed the behavioral deficits induced by LPS (0.83â¯mg/kg, i.p) in the tail suspension test, splash test and elevated plus maze. The pre-treatment of mice with WAY100635 (5-HT1A receptor antagonist), ketanserin (5-HT2A/2C receptor antagonist) and ondansetron (5-HT3 receptor antagonist) prevented the antidepressant- and anxiolytic-like effect elicited by CMI treatment after the LPS challenge. The administration of CMI also counteracted the increased expression of pro-inflammatory cytokines and indoleamine 2,3-dioxygenase (IDO) in the prefrontal cortex and hippocampus of mice challenged with LPS. Additionally, a molecular docking analysis showed that CMI binds to the active site of the serotonin transporter and IDO. These findings suggest that CMI reversed behavioral and biochemical alterations in the depression-anxiety comorbidity induced by LPS, possibly by modulation of neuroinflammatory mediators and the serotonergic system.
Subject(s)
Anti-Anxiety Agents/pharmacology , Antidepressive Agents/pharmacology , Anxiety/drug therapy , Behavior, Animal/drug effects , Depression/drug therapy , Hippocampus/drug effects , Indoleamine-Pyrrole 2,3,-Dioxygenase/drug effects , Indoles/pharmacology , Prefrontal Cortex/drug effects , Selenium Compounds/pharmacology , Serotonin Plasma Membrane Transport Proteins/drug effects , Animals , Anxiety/chemically induced , Anxiety/immunology , Depression/chemically induced , Depression/immunology , Disease Models, Animal , Lipopolysaccharides , Male , Mice , Molecular Docking SimulationABSTRACT
Serotonin (5-HT) plays a crucial role in modulating the afferent fiber discharge rate in the inferior colliculus, auditory cortex, and other nuclei of the ascending auditory system. Resveratrol, a natural polyphenol phytoalexin, can inhibit serotonin transporters (SERT) to increase synaptic 5-HT levels. In this study, we investigated the effects of resveratrol on noise-induced damage in the serotonergic system. Male Sprague-Dawley rats were anaesthetized and exposed to an 8-kHz tone at 116 dB for 3.5 h. Resveratrol (30 mg/kg, intraperitoneal injection [IP]) and citalopram (20 mg/kg, IP), a specific SERT inhibitor used as a positive control, were administered once a day for four consecutive days, with the first treatment occurring 2 days before noise exposure. Auditory brainstem response testing and positron emission tomography (PET) with N,N-dimethyl-2-(2-amino-4-[18F]fluorophenylthio)benzylamine (4-[18F]-ADAM, a specific radioligand for SERT) were used to evaluate functionality of the auditory system and integrity of the serotonergic system, respectively, before and after noise exposure. Finally, immunohistochemistry was performed 1 day after the last PET scan. Our results indicate that noise-induced serotonergic fiber loss occurred in multiple brain regions including the midbrain, thalamus, hypothalamus, striatum, auditory cortex, and frontal cortex. This noise-induced damage to the serotonergic system was ameliorated in response to treatment with resveratrol and citalopram. However, noise exposure increased the hearing threshold in the rats regardless of drug treatment status. We conclude that resveratrol has protective effects against noise-induced loss of SERT.