Sigma-1 Receptor Agonists and Their Clinical Implications in Neuropsychiatric Disorders

Accumulating evidence suggests that sigma-1 receptors play a role in the pathophysiology of neuropsychiatric diseases, as well as in the mechanisms of some selective serotonin reuptake inhibitors (SSRIs). Among the SSRIs, the order of affinity for sigma-1 receptors is as follows: fluvoxamine > sertraline > fluoxetine > escitalopram > citalopram >> paroxetine. Some SSRIs (e.g., fluvoxamine, fluoxetine and escitalopram) and other drugs (donepezil , ifenprodil , dehydroepiandeterone (DHEA)) potentiate nerve-growth factor (NGF)-induced neurite outgrowth in PC12 cells, and these effects could be antagonized by the selective sigma-1 receptor antagonist NE-100. Furthermore, fluvoxamine, donepezil, and DHEA, but not paroxetine or sertraline, improved phencyclidine-induced cognitive deficits in mice, and these effects could be antagonized by NE-100. Several clinical studies showed that sigma-1 receptor agonists such as fluvoxamine and ifenprodil could have beneficial effects in patients with neuropsychiatric disorders. In this chapter, the authors will discuss the role of sigma-1 receptors in the mechanistic action of some SSRIs, donepezil, neurosteroids, and ifenprodil, and the clinical implications for sigma-1 receptor agonists .

Fluvoxamine inhibits some inflammatory genes expression in LPS/stimulated human endothelial cells, U937 macrophages, and carrageenan-induced paw edema in rat

OBJECTIVES

Fluvoxamine is a well-known selective serotonin reuptake inhibitor (SSRI); Despite its anti-inflammatory effect, little is known about the precise mechanisms involved. In our previous work, we found that IP administration of fluvoxamine produced a noticeable anti-inflammatory effect in carrageenan-induced paw edema in rats. In this study, we aimed to evaluate the effect of fluvoxamine on the expression of some inflammatory genes like intercellular adhesion molecule (ICAM₁), vascular cell adhesion molecule (VCAM₁), cyclooxygenases2 (COX₂), and inducible nitric oxide synthase (iNOS).

MATERIALS AND METHODS

An in vitro model of LPS stimulated human endothelial cells and U937 macrophages were used. Cells were pretreated with various concentrations of fluvoxamine, from 10^-8 M to 10^-6 M. For in vivo model, fluvoxamine was administered IP at doses of 25 and 50 mg/kg^-1 , before injection of carrageenan. At the end of experiment, the expression of mentioned genes were measured by quantitative real time (RT)-PCR in cells and in paw edema in rat.

RESULTS

The expression of ICAM₁, VCAM₁, COX₂, and iNOS was significantly decreased by fluvoxamine in endothelial cells, macrophages, and in rat carrageenan-induced paw edema. Our finding also confirmed that IP injection of fluvoxamine inhibits carrageenan-induced inflammation in rat paw edema.

CONCLUSION

The results of present study provide further evidence for the anti-inflammatory effect of fluvoxamine. This effect appears to be mediated by down regulation of inflammatory genes. Further studies are needed to evaluate the complex cellular and molecular mechanisms of immunomodulatory effect of fluvoxamine.

The role of sigma-1 receptor and brain-derived neurotrophic factor in the development of diabetes and comorbid depression in streptozotocin-induced diabetic rats

RATIONALE

Depression is highly prevalent in diabetes (DM). Brain-derived neurotrophic factor (BDNF) which is mainly regulated by the endoplasmic reticulum chaperon sigma-1 receptor (S1R) plays a relevant role in the development of depression.

OBJECTIVES

We studied the dose-dependent efficacy of S1R agonist fluvoxamine (FLU) in the prevention of DM-induced depression and investigated the significance of the S1R-BDNF pathway.

METHODS

We used streptozotocin to induce DM in adult male rats that were treated for 2 weeks p.o. with either different doses of FLU (2 or 20 mg/bwkg) or FLU + S1R antagonist NE100 (1 mg/bwkg) or vehicle. Healthy controls were also enrolled. Metabolic, behaviour, and neuroendocrine changes were determined, and S1R and BDNF levels were measured in the different brain regions.

RESULTS

In DM rats, immobility time was increased, adrenal glands were enlarged, and thymuses were involuted. FLU in 20 mg/bwkg, but not in 2 mg/bwkg dosage, ameliorated depression-like behaviour. S1R and BDNF protein levels were decreased in DM, while FLU induced SIR-BDNF production. NE100 suspended all effects of FLU.

CONCLUSIONS

We suggest that disturbed S1R-BDNF signaling in the brain plays a relevant role in DM-induced depression. The activation of this cascade serves as an additional target in the prevention of DM-associated depression.

The clinical potentials of adjunctive fluvoxamine to clozapine treatment: a systematic review

RATIONALE

New clozapine optimization strategies are warranted, as some patients do not achieve sufficient response and experience various adverse effects. Fluvoxamine is a potent CYP1A2 inhibitor and may increase the ratio of clozapine to its primary metabolite N-desmethylclozapine (NDMC).

OBJECTIVES

This study aims to review all pharmacodynamic effects and the adverse effect profile of changing the clozapine/NDMC ratio with adjunctive fluvoxamine.

METHODS

MEDLINE, Embase, and the Cochrane Library were searched with the search terms "clozapine" and "fluvoxamine" without any time limit. Language was restricted to English, Scandinavian, Polish, and German. Studies were sorted for relevance based on title and abstract. Clinical recommendations of potential indications/effects were graded as level A, B, C, or D depending on studies of high, moderate, low, or very low quality, respectively.

RESULTS

Based on data from 24 case reports/series, seven cohort studies, and two randomized controlled trials, 241 patients were studied. Evidence (A) supported that adjunctive fluvoxamine increased clozapine plasma levels. This may increase the probability of response in patients, where sufficient clozapine plasma levels cannot be achieved. Adjunctive fluvoxamine reduced metabolic adverse effects of clozapine (B) but not agranulocytosis risk (B). Although depressive or obsessive-compulsive symptoms may improve, a SSRI with no CYP1A2 inhibition should rather be used (C). No studies investigated the effect of adjunctive fluvoxamine to minimize clozapine rebound psychosis (D) or to reduce the effects of smoking on clozapine plasma levels (D).

CONCLUSIONS

Adjunctive fluvoxamine may have clinical potentials for optimizing clozapine treatment but further clinical studies are warranted to explore the clinical implications.

Fluvoxamine alleviates paclitaxel-induced neurotoxicity

Paclitaxel (Px) is an effective chemotherapeutic agent for the treatment of various cancers. However, it is often associated with neurological side effects, including chemotherapy-associated cognitive impairment (CACI), such as "chemobrain". Previously, we reported that endoplasmic reticulum (ER) stress is involved in Px-induced neurotoxicity, and immunoglobulin heavy chain binding protein (BiP) inducer X (BIX) alleviates Px-induced neurotoxicity. However, BIX has not been used in clinical practice yet. We recently reported that fluvoxamine (Flv) alleviates ER stress via induction of sigma-1 receptor (Sig-1R). The purpose of this study was to investigate whether Flv could alleviate Px-induced neurotoxicity in vitro. SK-N-SH cells were pre-treated for 12 h with or without 10 μg/ml Flv followed by treatment with 1 μM Px with or without co-existence of 10 μg/ml Flv for 24 h. To investigate the involvement of Sig-1R in alleviation effect on Px-induced neurotoxicity,1 μM NE100, an antagonist of Sig-1R, was added for 24 h. Neurotoxicity was assessed using the MTS viability assay and ER stress-mediated neurotoxicity was assessed by evaluating the expression of C/EBP homologous protein (CHOP), cleaved caspase 4, and cleaved caspase 3. Pre-treatment with Flv significantly alleviated the induction of CHOP, cleaved caspase 4, and cleaved caspase 3 in SK-N-SH cells. At the same time, pre-treatment with Flv significantly induced Sig-1R in SK-N-SH cells. In addition, viability was significantly higher in Flv-treated cells than in untreated cells, which was reversed by treatment with NE100. Our results suggest that Flv alleviates Px-induced neurotoxicity in part through the induction of Sig-1R. Our findings should contribute to one of the novel approaches for the alleviation of Px-induced neurotoxicity, including chemobrain.

Effects of selective serotonin reuptake inhibitors on three sex steroids in two versions of the aromatase enzyme inhibition assay and in the H295R cell assay

Selective serotonin reuptake inhibitors are known to have a range of disorders that are often linked to the endocrine system e.g. hormonal imbalances, breast enlargement, sexual dysfunction, and menstrual cycle disorders. The mechanisms behind most of these disorders are not known in details. In this study we investigated whether the endocrine effect due to SSRI exposure could be detected in well adopted in vitro steroidogenesis assays, two versions of the aromatase enzyme inhibition assay and the H295R cell assay. The five drugs citalopram, fluoxetine, fluvoxamine, paroxetine and sertraline, were shown to inhibit the aromatase enzyme in both types of aromatase assays. The IC50 values ranged from 3 to 600 μM. All five SSRIs, were further investigated in the H295R cell line. All compounds altered the steroid secretion from the cells, the lowest observed effect levels were 0.9 μM and 3.1 μM for sertraline and fluvoxamine, respectively. In general the H295R cell assay was more sensitive to SSRI exposure than the two aromatase assays, up to 20 times more sensitive. This indicates that the H295R cell line is a better tool for screening endocrine disrupting effects. Our findings show that the endocrine effects of SSRIs may, at least in part, be due to interference with the steroidogenesis.

Assignment refusal and its relation to outcome in a randomized controlled trial comparing Cognitive Therapy and Fluvoxamine in treatment-resistant patients with obsessive compulsive disorder

The effectiveness of Fluvoxamine was compared to that of Cognitive Therapy (CT) in a 12-week randomized controlled trial (RCT) in 48 patients with obsessive-compulsive disorder (OCD), who were treatment-resistant to a previous behavior therapy (BT). A considerable amount of patients did not comply with the assigned treatment and switched treatments. The aim of this study was to identify patient characteristics predictive of assignment compliance and to study whether these characteristics were related to outcome. A logistic model, based on psychological and social patient characteristics, in addition to or in interaction with the assignment, was used for the explanation of compliance with treatment assignment. Especially patients who have a higher score on the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) tend to comply with the effective Fluvoxamine treatment. The same set of variables was related to both compliance and outcome of therapy received. Therefore, the logistic model of compliance could be used to reduce the positive bias of As-Treated analysis (AT). The difference between the results of Fluvoxamine and Cognitive Therapy remained statistically significant after correcting for the positive bias as the result of assignment refusal and after applying the assumption that two drop-out patients needed imputation of lesser results.

A Stability Indicating HPLC Method for the Determination of Fluvoxamine in Pharmaceutical Dosage Forms

Fluvoxamine maleate is a selective serotonin reuptake inhibitor, which is used for the treatment of different types of depressive disorders. In the present study, a stability indicating HPLC method was developed and validated for the determination of fluvoxamine maleate. The chromatographic separation was carried out using a Nova-Pak CN column and a mixture of K2HPO4 50 mM (pH 7.0) and acetonitrile (60: 40, v/v) as the mobile phase. Target compounds were detected using a UV detector set at 235 nm. The developed method was linear over the concentration range of 1-80 μg/ml with acceptable precision (CV values < 2.0%) and accuracy (error values < 1.6%). The degradation studies showed that fluvoxamine maleate is relatively unstable under acidic, basic and oxidative conditions and also when exposed to UV radiation. On the other hand, the bulk powder of fluvoxamine maleate was relatively stable when exposed to visible light or heat. The proposed method was successfully applied for the determination of active ingredient of fluvoxamine dosage form without any interference from tablet excipients.

Evaluation of anti-colitic effect of fluvoxamine against acetic acid-induced colitis in normal and reserpinized depressed rats

High prevalence of psychological comorbidities such as depression and anxiety in patients with inflammatory bowel disease (IBD) supports the premise that adding an anti-depressant drug with known anti-inflammatory effect to the medical treatment have beneficial effect in the course of the underlying disease. Colitis was induced by intracolonic instillation of 2 ml of 4% v/v acetic acid solution in rats. Anti-colitic effect of fluvoxamine was evaluated in two categories: A: normal rats, B: reserpinized (6 mg/kg, i.p.) depressed rats. In group A, fluvoxamine (2.5, 5, 10 mg/kg, i.p.) was administered 2 h after induction of colitis and in group B: reserpine (6 mg/kg, i.p.) was administered 1 h prior to colitis induction and then fluvoxamine (2.5, 5, 10 mg/kg, i.p.) was administered 2 h after colitis induction. Dexamethasone (1 mg/kg) was used as reference drug. All the treatments continued daily for five days. The effect was assessed on the basis of macroscopic score, biochemical (myeloperoxidase) changes and histopathological studies. Results showed that fluvoxamine (2.5 and 5 mg/kg) and dexamethasone treatment markedly reduced disease severity in both reserpinized and non-reserpinized rats as indicated by reduction in macroscopic and microscopic colonic damages while reserpine adversely exacerbated the colitis damage. Myeloperoxidase activity which was increased following colitis induction was also decreased. The findings of this study elucidate the anti-colitic and anti-inflammatory properties of fluvoxamine and so introduced it as a good candidate to treat depressive symptoms in people comorbid to IBD.

Serotonin: a never-ending story

The neurotransmitter serotonin is an evolutionary ancient molecule that has remarkable modulatory effects in almost all central nervous system integrative functions, such as mood, anxiety, stress, aggression, feeding, cognition and sexual behavior. After giving a short outline of the serotonergic system (anatomy, receptors, transporter) the author's contributions over the last 40 years in the role of serotonin in depression, aggression, anxiety, stress and sexual behavior is outlined. Each area delineates the work performed on animal model development, drug discovery and development. Most of the research work described has started from an industrial perspective, aimed at developing animals models for psychiatric diseases and leading to putative new innovative psychotropic drugs, like in the cases of the SSRI fluvoxamine, the serenic eltoprazine and the anxiolytic flesinoxan. Later this research work mainly focused on developing translational animal models for psychiatric diseases and implicating them in the search for mechanisms involved in normal and diseased brains and finding new concepts for appropriate drugs.

Promoter variation in the catechol-O-methyltransferase gene is associated with remission of symptoms during fluvoxamine treatment for major depression

We investigated the association between remission of depressive symptoms in fluvoxamine treatment and catechol-O-methyltransferase (COMT) gene. Sixteen SNPs in the COMT gene were investigated in 123 outpatients with major depression. Three single nucleotide polymorphisms located in the 5' region were associated with remission in fluvoxamine-treated outpatients with moderate to severe depression.

Serotonin and sudden death: differential effects of serotonergic drugs on seizure-induced respiratory arrest in DBA/1 mice

In the DBA/1 mouse model of sudden unexpected death in epilepsy (SUDEP), administration of a selective serotonin (5-HT) reuptake inhibitor (SSRI), fluvoxamine, completely suppressed seizure-induced respiratory arrest (S-IRA) at 30 min after administration (i.p.) in a dose-related manner without blocking audiogenic seizures (AGSz), but another SSRI, paroxetine, reduced S-IRA but with a delayed (24 h) onset and significant toxicity. A serotonin-norepinephrine reuptake inhibitor, venlafaxine, reduced S-IRA incidence, but higher doses were ineffective. A selective 5-HT7 agonist, AS-19, was totally ineffective in reducing S-IRA. In developing DBA/1 mice that had not previously experienced AGSz, administration of a nonselective 5-HT antagonist, cyproheptadine, induced a significantly greater incidence of S-IRA than that of saline. This study confirms that certain drugs that enhance the activation of 5-HT receptors are able to prevent S-IRA, but not all serotonergic drugs are equally effective, which may be relevant to the potential use of these drugs for SUDEP prevention. Serotonergic antagonists may be problematic in patients with epilepsy.

Fluvoxamine moderates reduced voluntary activity following chronic dexamethasone infusion in mice via recovery of BDNF signal cascades

Major depression is a complex disorder characterized by genetic and environmental interactions. Selective serotonin reuptake inhibitors (SSRIs) effectively treat depression. Neurogenesis following chronic antidepressant treatment activates brain derived neurotrophic factor (BDNF) signaling. In this study, we analyzed the effects of the SSRI fluvoxamine (Flu) on locomotor activity and forced-swim behavior using chronic dexamethasone (cDEX) infusions in mice, which engenders depression-like behavior. Infusion of cDEX decreased body weight and produced a trend towards lower locomotor activity during darkness. In the forced-swim test, cDEX-mice exhibited increased immobility times compared with mice administered saline. Flu treatment reversed decreased locomotor activity and mitigated forced-swim test immobility. Real-time polymerase chain reactions using brain RNA samples yielded significantly lower BDNF mRNA levels in cDEX-mice compared with the saline group. Endoplasmic reticulum stress-associated X-box binding protein-1 (XBP1) gene expression was lower in cDEX-mice compared with the saline group. However, marked expression of the XBP1 gene was observed in cDEX-mice treated with Flu compared with mice given saline and untreated cDEX-mice. Expression of 5-HT2A and Sigma-1 receptors decreased after cDEX infusion compared with the saline group, and these decreases normalized to control levels upon Flu treatment. Our results indicate that the Flu moderates reductions in voluntary activity following chronic dexamethasone infusions in mice via recovery of BDNF signal cascades.

Serum proBDNF/BDNF and response to fluvoxamine in drug-naïve first-episode major depressive disorder patients

BACKGROUND

We investigated the association between serum proBDNF, a precursor of brain-derived neurotrophic factor (BDNF), and response to fluvoxamine in patients with major depressive disorder (MDD) using the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR): physically healthy and free of current alcohol or drug abuse, comorbid anxiety, or personality disorders.

METHODS

Fifty-one patients with MDD (M/F, 19:32; age, 38 ± 19 years) and 51 healthy controls (M/F, 22:29; age, 34 ± 17 years) were studied using DSM-IV-TR: physically healthy and free of current alcohol or drug abuse, comorbid anxiety, or personality disorders. Serum levels of proBDNF and MDNF were measured by sandwich enzyme-linked immunosorbent assay (ELISA).

RESULTS

Serum mature BDNF levels in the MDD patients were significantly lower than those in the healthy controls (t = 3.046, p = 0.0018). On the other hand, no difference was found in serum proBDNF between the MDD patients and the healthy controls (t = -0.979, p = 0.833). A trend of negative correlation was found between baseline serum BDNF and baseline scores of the 17 items of the Hamilton Rating Scale for Depression (HAMD17) (r = -0.183, p = 0.071). No correlation was however found between HAMD17 scores and proBDNF at baseline (r = 0.092, p = 0.421). Furthermore, no correlation was observed between baseline HAMD17 scores and baseline proBDNF/BDNF (r = -0.130, p = 0.190). No changes were observed in serum levels of proBDNF and BDNF during the treatment periods.

CONCLUSIONS

These results suggest that there is no association between serum proBDNF/BDNF and fluvoxamine response in MDD patients at least within 4 weeks of the treatment.

Fluvoxamine rescues mitochondrial Ca2+ transport and ATP production through σ(1)-receptor in hypertrophic cardiomyocytes

AIMS

We previously reported that fluvoxamine, a selective serotonin reuptake inhibitor with high affinity for the σ1-receptor (σ1R), ameliorates cardiac hypertrophy and dysfunction via σ1R stimulation. Although σ1R on non-cardiomyocytes interacts with the IP3 receptor (IP3R) to promote mitochondrial Ca(2+) transport, little is known about its physiological and pathological relevance in cardiomyocytes.

MAIN METHODS

Here we performed Ca(2+) imaging and measured ATP production to define the role of σ1Rs in regulating sarcoplasmic reticulum (SR)-mitochondrial Ca(2+) transport in neonatal rat ventricular cardiomyocytes treated with angiotensin II to promote hypertrophy.

KEY FINDING

These cardiomyocytes exhibited imbalances in expression levels of σ1R and IP3R and impairments in both phenylephrine-induced mitochondrial Ca(2+) mobilization from the SR and ATP production. Interestingly, σ1R stimulation with fluvoxamine rescued impaired mitochondrial Ca(2+) mobilization and ATP production, an effect abolished by treatment of cells with the σ1R antagonist, NE-100. Under physiological conditions, fluvoxamine stimulation of σ1Rs suppressed intracellular Ca(2+) mobilization through IP3Rs and ryanodine receptors (RyRs). In vivo, chronic administration of fluvoxamine to TAC mice also rescued impaired ATP production.

SIGNIFICANCE

These results suggest that σ1R stimulation with fluvoxamine promotes SR-mitochondrial Ca(2+) transport and mitochondrial ATP production, whereas σ1R stimulation suppresses intracellular Ca(2+) overload through IP3Rs and RyRs. These mechanisms likely underlie in part the anti-hypertrophic and cardioprotective action of the σ1R agonists including fluvoxamine.

Benefical effects of sigma-1 agonist fluvoxamine for tardive dyskinesia and tardive akathisia in patients with schizophrenia: report of three cases

Fluvoxamine is a selective serotonin reuptake inhibitor that is approved for psychiatric disorders such as major depressive episodes and obsessive-compulsive disorder. Beside inhibition of serotonin reuptake, fluvoxamine is also a potent agonist of endoplasmic reticulum (ER) protein sigma-1 receptors, which play a role in the pathophysiology of a number of psychiatric and neurodegenerative disorders. This report presents beneficial effects of sigma-1 agonist fluvoxamine on hyperkinetic movement disorders such as tardive dyskinesia and tardive akathisia. Fluvoxamine might be a novel treatmet approach in the treatment of hyperkinetic movement disorders.

Effect of Animal Condition and Fluvoxamine on the Result of [(18)F]N-3-Fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl) Nortropane ([(18)F]FP-CIT) PET Study in Mice

PURPOSE

PET (positron emission tomography) is a noninvasive imaging technique, visualizing biological aspects in vivo. In animal models, the result of PET study can be affected more prominently than in humans by the animal conditions or drug pretreatment. We assessed the effects of anesthesia, body temperature, and pretreatment with selective serotonin reuptake inhibitor on the results of [(18)F]N-3-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl) nortropane ([(18)F]FP-CIT) PET in mice.

METHODS

[(18)F]FP-CIT PET of C57BL/6 mice was performed in three different conditions: (1) anesthesia (isoflurane) with active warming (38°C) as a reference; (2) no anesthesia or warming; (3) anesthesia without warming at room temperature. Additional groups of mice pretreated with escalating doses of fluvoxamine (5, 20, 40, 80 mg/kg) were imaged in condition (1). The time activity curve and standardized uptake value of the striatum, cerebral cortex, and bone were compared among these conditions.

RESULTS

In all conditions, radioactivities of the striatum and cortex tended to form a plateau after rapid uptake and washout, but that of bone tended to increase gradually. When anesthetized without any warming, all the mice developed hypothermia and showed reduced bone uptake with slightly increased striatal and cortical uptakes compared to the reference condition. In conditions without anesthesia, striatal and cortical uptakes were reduced, whereas the bone uptake showed no change. Pretreatment with fluvoxamine increased the striatal uptake and striatal specific to cortical non-specific uptake ratio, whereas the bone uptake was reduced.

CONCLUSION

Anesthesia, body temperature, and fluvoxamine affect the result of [(18)F]FP-CIT PET in mice by altering striatal and bone uptakes.

The Selective Serotonin Reuptake Inhibitor Paroxetine, but not Fluvoxamine, Decreases Methamphetamine Conditioned Place Preference in Mice

Monoamine transporters are the main targets of methamphetamine (METH). Recently, we showed that fluoxetine, a selective serotonin reuptake inhibitor (SSRI), decreased METH conditioned place preference (CPP), suggesting that serotonin transporter (SERT) inhibition reduces the rewarding effects of METH. To further test this hypothesis, in the present study we investigated the effects of additional SSRIs, paroxetine and fluvoxamine, on METH CPP in C57BL/6J mice. In the CPP test, pretreatment with 20 mg/kg paroxetine abolished the CPP for METH, whereas pretreatment with 100 mg/kg fluvoxamine prior to administration of METH failed to inhibit METH CPP. These results suggest that paroxetine, a medication widely used to treat depression, may be a useful tool for treating METH dependence. Further, these data suggest that molecules other than the SERT [such as G protein-activated inwardly rectifying K+ (GIRK) channels] whose activities are modulated by paroxetine and fluoxetine, but not by fluvoxamine, are involved in reducing METH CPP by paroxetine and fluoxetine.

Effect of fluvoxamine on carrageenan-induced paw edema in rats evaluation of the action sites

The present study was designed to explore the anti-inflammatory effect of fluvoxamine, as a selective serotonin reuptake inhibitor (SSRI) anti-depressant, on carrageenan-induced paw edema in more details. At first, fluvoxamine was administered intra-peritoneally (2.5, 12.5, 25 and 50 mg Kg(-1)) 30 min before the subplantar injection of carrageenan. Fluvoxamine was also injected intra-peritoneally at a dose of 50 mg Kg(-1) 30 or 90 min after carrageenan injection. Then, fluvoxamine was given intra-cerebroventricularly (25, 50 and 100 μg/rat) and intra-thecally (25, 50 and 100 μg/rat) 30 min before the carrageenan challenge. Finally, the effect of mifepristone (5 mg Kg(-1)), an antagonist of the glucocorticoid receptor, on the anti-edema effect of fluvoxamine (50 mg Kg(-1)) was investigated. Results showed that intra-peritoneal (IP) administration of fluvoxamine before or after carrageenan injection considerably inhibited paw edema response at 4 h post-carrageenan (p < 0.001), but intra-cerebroventricular (i.c.v.) and intra-thecal (i.t.) injection of fluvoxamine did not alter the degree of paw swelling. The inhibitory effect of fluvoxamine was reduced by the pretreatment of mifepristone (p < 0.01). Our results suggest that IP administration of fluvoxamine produces a noticeable anti-inflammatory effect in the carrageenan-induced paw edema in rats and at least, a part of this effect is mediated through glucocorticoid receptor. Moreover, it seems unlikely that central sites have an important role in this inhibitory effect of fluvoxamine.

Study of the effect of nortriptyline and fluvoxamine on psychomotor functions in healthy volunteers

BACKGROUND

Today, many antidepressants are available, but they often cause adverse effects, particularly psychomotor and cognitive. It leads to patient maladjustment and may impair psychomotor performance. Fluvoxamine is a newer antidepressant and hence the present study was planned to investigate its effect on psychomotor functions and compare with nortriptyline and record their adverse reactions.

MATERIALS AND METHODS

A total of 26 healthy volunteers were included in this double-blind, placebocontrolled, crossover study. Single oral doses of fluvoxamine 50 mg, nortriptyline 50 mg and placebo were administered following a Latin square design. The objective parameters-six digit cancellation test, digit symbol substitution test, critical flicker fusion test, arithmetic ability test, hand steadiness test and subjective parameters such as visual analogue scale 1, 2, 3 were tested at 0, 2 and 4 h. The side-effects were also investigated.

RESULTS

Nortriptyline impaired all subjective and objective psychomotor functions while fluvoxamine did not show any significant effect on objective tests. However, on subjective parameters, there was a significant effect. The side-effects observed were dryness of mouthwith the nortriptyline and nausea and headache with fluvoxamine.

CONCLUSION

Fluvoxamine is a better antidepressant drug in comparison with nortriptyline as it causes a less impairment of psychomotor functions.

Changes of functional MRI findings in a patient whose pathological gambling improved with fluvoxamine

Legalized gambling is a growing industry, and is probably a factor in the presently increasing prevalence of pathological gambling. We present a case of a 36-year-old pathological gambler who was treated with fluvoxamine, a selective serotonin reuptake inhibitor, and who was assessed by functional MRI before and after drug administration. During activation periods, the pathological gambler was shown cards as stimuli, and fMRI results in several brain regions showed differential effects before and after medication and a maintenance period. This case demonstrates that the treatment response to fluvoxamine in a pathological gambler was observed not only by subjective self-report, but also by objective fMRI results. Therefore, fMRI may be a useful tool in the diagnosis and prediction of treatment response in patients afflicted with pathological gambling.

Fluvoxamine for the treatment of depression and parkinsonism in progressive supranuclear palsy

Progressive supranuclear palsy (PSP) is a parkinsonian-like disorder characterized by postural instability, rigidity, bradykinesia, supranuclear ocular palsy, dysarthria, dysphagia and dementia. There is no satisfactory treatment. A 68-year-old woman with initial progressive supranuclear palsy is described, who was generally apathetic, withdrawn, lacked spontaneity in speech and behavior, and suffered episodes of depression. Treatment with levodopa/carbidopa was ineffective in controlling her parkinsonism and depression, but these symptoms responded to fluvoxamine. This response may be related to fluvoxamine's putative effect on the serotonin system.