The selective serotonin reuptake inhibitor citalopram induces the storage of serotonin in catecholaminergic terminals.
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We investigated whether selective inhibition of serotonin (5-hydroxytryptamine; 5-HT) transporter with citalopram leads to accumulation of 5-HT in catecholaminergic neurons. In the rabbit olfactory tubercle, citalopram (1-10 microM) inhibited [(3)H]5-HT uptake; however, the maximal degree of inhibition achieved was 70%. Addition of nomifensine (1-10 microM) was required for complete inhibition of [(3)H]5-HT uptake. In slices labeled with 0.1 microM [(3)H]5-HT, cold 5-HT (0.03-1 microM) induced a large increase in the efflux (release) of stored [(3)H]5-HT, an effect blocked by coperfusion with 1 microM citalopram. Similar concentrations (0.03-1 microM) of norepinephrine (NE) or dopamine (DA) failed to release [(3)H]5-HT. When labeling with 0.1 microM [(3)H]5-HT was carried out in the presence of citalopram, 1) low concentrations of 5-HT failed to release [(3)H]5-HT; 2) DA and NE were more potent and effective in releasing [(3)H]5-HT than in control slices; 3) coperfusion of NE, DA, or 5-HT with citalopram enhanced the release of [(3)H]5-HT induced by the catecholamines but not by 5-HT; and 4) coperfusion of NE or DA with nomifensine antagonized NE- and DA-evoked [(3)H]5-HT release, with a greater effect on NE than on DA. These results suggest that in the rabbit olfactory tubercle, where there is coexistence of 5-HT, NE, and DA neurons, inhibition of the 5-HT transporter led to accumulation of 5-HT in catecholaminergic terminals. Thus, during treatment with selective serotonin uptake inhibitors (SSRIs), 5-HT may be stored in catecholaminergic neurons acting as a false neurotransmitter and/or affecting the disposition of DA and/or NE. Transmitter relocation may be involved in the antidepressant action of SSRIs. (+info)
Efficacy of citalopram in the prevention of recurrent depression in elderly patients: placebo-controlled study of maintenance therapy.
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BACKGROUND: The highly recurrent nature of major depression in the young and the elderly warrants long-term antidepressant treatment. AIMS: To compare the prophylactic efficacy of citalopram and placebo in elderly patients; to evaluate long-term tolerability of citalopram. METHOD: Out-patients, > or =65 years, with unipolar major depression (DSM-IV: 296.2 x or 296.3 x) and Montgomery-Asberg Depression Rating Scale score > or =22 were treated with citalopram 20-40 mg for 8 weeks. Responders continued on their final fixed dose of citalopram for 16 weeks before randomisation to double-blind treatment with citalopram or placebo for at least 48 weeks. RESULTS: Nineteen of the 60 patients using citalopram v. 41 of the 61 patients using placebo had recurrence. Time to recurrence was significantly different between citalopram- and placebo-patients, in favour of citalopram (log-rank test, P<0.0001). Long-term treatment was well tolerated. CONCLUSIONS: Long-term treatment with citalopram is effective in preventing recurrence of depression in the elderly and is well tolerated. (+info)
Serotonin transporter promoter variants in autism: functional effects and relationship to platelet hyperserotonemia.
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The well-replicated platelet hyperserotonemia of autism has stimulated interest in serotonin (5-HT) in autism. We have examined the effects of the serotonin transporter gene (5-HTT, locus SLC6A4) promoter polymorphism (5-HTTLPR) on platelet 5-HT physiology in autism. Platelet 5-HT uptake rates and affinities (V(max) and K(m)), uptake site densities (B(max)) and 5-HT levels were examined in 31 French individuals with autism genotyped with respect to the 5-HTTLPR. Platelet 5-HT uptake and 5-HT levels were measured using HPLC; uptake sites were determined by radioligand binding. A 1.5-fold increased rate (V(max)) of platelet 5-HT uptake was observed in ll genotype individuals compared to those with ls and ss genotypes (Mann- Whitney U-test, P = 0.022). However, no significant relationship was observed between genotype and uptake site density (U-test, P = 0.51). Although median levels of platelet 5-HT in platelet-rich plasma were higher in the ll group, only trend level significance was observed (U-test, P= 0.069); platelet 5-HT content measured in whole blood was similar across genotypes. Uptake rates were well correlated with B(max) values (r = 0.66, P = 0.002); correlations between uptake and platelet 5-HT levels and between B(max) values and 5-HT levels were somewhat lower. While 5-HTTLPR alleles had an appreciable effect on platelet 5-HT uptake rates, effects on 5-HT levels and uptake site density were smaller or absent. Based on these preliminary data and prior studies of allele frequencies, we conclude that the 5-HTTLPR is not a major determinant of the group mean platelet serotonin elevation seen in autism. However, a role for increased uptake in the hyperserotonemia of autism can not be ruled out. In addition, it appears that studies of platelet 5-HT measures in autism and other disorders should take account of the effects of 5-HTTLPR genotype on 5-HT uptake (+info)
Citalopram inhibits L-type calcium channel current in rat cardiomyocytes in culture.
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Selective serotonine reuptake inhibitors (SSRI) are believed to be less dangerous in the treatment of depressive disorder in comparison with tricyclic antidepressants (TCA) due to their relative lack of cardiotoxicity. Thus, we investigated the effect of citalopram (SSRI) on membrane electrophysiology in rat cardiomyocytes in tissue culture. The results were compared with those from amitriptyline (TCA). The whole-cell configuration patch-clamp technique was used. Both citalopram and amitriptyline exhibited the concentration-dependent inhibition of the L-type calcium channel current (ICa). Citalopram in concentrations of 3 microM and 10 microM inhibited peak calcium current by 2.7% and 8%, respectively. We demonstrated the same potency of citalopram and amitriptyline to inhibit ICa. These observations led us to conclude that citalopram and amitriptyline are drugs, which exhibit a similar potency for causing concentration-dependent inhibition of ICa. (+info)
A prospective study of the incidence and open-label treatment of interferon-induced major depressive disorder in patients with hepatitis C.
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Interferon (IFN) therapy has been associated with the development of Major Depressive Disorder (MDD) when given to patients with hepatitis C (HCV). The incidence, time course, risk factors, and treatment of IFN-induced MDD are poorly understood. The objectives of the present study were to determine the incidence of IFN-induced MDD, as well as to determine the efficacy of open-label antidepressant treatment, in particular selective serotonin reuptake inhibitors (SSRIs) for IFN-induced MDD. Thirty-nine HCV patients on IFN therapy were monitored weekly using the Beck Depression Inventory (BDI). Those who became depressed were treated with citalopram, a SSRI antidepressant. Main outcome measures included the incidence of IFN-induced MDD, as well as response rates to antidepressants in those patients who developed IFN-induced MDD. Our results showed that 13 of 39 patients (33%) developed IFN-induced MDD. There were no differences in age, gender, past history of MDD, or substance use between those who became depressed and those who did not. However, there were significantly fewer African American patients in the depressed group. Patients who developed IFN-induced MDD were on IFN therapy for an average of 12.1 weeks prior to the development of MDD. Eleven of 13 patients (85%) were responsive to antidepressant treatment. We conclude that IFN-induced MDD is common in HCV patients. Health care providers should follow IFN-treated HCV patients for the development of MDD, particularly between the 2nd and 5th months of IFN therapy. SSRIs, in particular citalopram, are an effective treatment for IFN-induced depression in HCV patients. (+info)
Effect of YM992, a novel antidepressant with selective serotonin re-uptake inhibitory and 5-HT 2A receptor antagonistic activity, on a marble-burying behavior test as an obsessive-compulsive disorder model.
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YM992 ((S)-2-[[(7-fluoroindan-4-yl)oxy]methyl]morpholine) monohydrochloride is a novel antidepressant with selective serotonin (5-hydroxytryptamine, 5-HT) re-uptake inhibition and 5-HT(2A) receptor antagonistic activity. The effects of YM992 and two selective 5-HT re-uptake inhibitors (SSRIs) were studied in a marble-burying behavior test as a model of an obsessive-compulsive disorder (OCD) in mice at doses of 5, 10 and 15 mg/kg, i.p. YM992 and fluoxetine significantly inhibited marble-burying behavior at a dose of 15 mg/kg (i.p.) without affecting spontaneous locomotor activities. Citalopram also significantly inhibited the behavior at doses of 5, 10 and 15 mg/kg (i.p.) without affecting spontaneous locomotor activities. These results suggest that YM992, as well as SSRIs, may exhibit anti-OCD activity in addition to an antidepressive effect in clinical use. (+info)
The efficacy of citalopram in the treatment of premature ejaculation: a placebo-controlled study.
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BACKGROUND: Despite the limited number of available study comparing of their efficacy, selective serotonin re-uptake inhibitors (SSRI) have been thought to have beneficial effects for the patients with premature ejaculation. In the present study, we decided to examine the efficacy of citalopram, an SSRI, in the treatment of premature ejaculation. METHOD: The study was consisted of 26 married patients diagnosed with premature ejaculation according to Diagnostic and Statistical Manual of Mental Disorders Third Revised Version (DSM-III-R). The patients were randomly assigned to two groups, citalopram (group I) and placebo (group II), each consisting of 13 patients. The effects of drug on the ejaculatory function were assessed by the intravaginal ejaculation latency time. Additionally, all patients were screened by using Clinical Global Impression-Improvement Scale (CGI-I) and Yonsei Sexual Function Inventory-II (YSFI-II). RESULTS: The increase in the intravaginal ejaculation latency time in the citalopram group was statistically significant than that of placebo group. In addition, with respect to the subscales of the YSFI-II scale, similar overall significant improvements were seen in the patients given citalopram compared to those given placebo. Of group I patients, five (38.5%) were considered as 'very much improved' and four (30.8%) 'much improved' by CGI-I and only one of group II patients (7.7%) showed 'much improved'. CONCLUSION: The patients treated with citalopram showed significantly greater improvement compared to the patients receiving placebo. (+info)
Acute SSRI administration affects the processing of social cues in healthy volunteers.
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Enhancement of serotonin neurotransmission plays an important role in the antidepressant response to agents presently available to treat depression. This response forms the major evidence for the role of serotonin in affective and social behaviour in humans. The present study investigated the effects of acute administration of the selective serotonin reuptake inhibitor (SSR1), citalopram (10 mg, i.v.) upon a measure of emotional processing in healthy female volunteers. Subjects completed a facial expression recognition task following infusion of citalopram or saline (between-subjects design, double-blind). Facial expressions associated with five basic emotions--happiness, sadness, fearfulness, anger and disgust--were displayed. Each face had been 'morphed' between neutral (0%) and each emotional standard (100%) in 10% steps, leading to a range of emotional intensities. Mood and subjective experience were also monitored throughout the testing session. Volunteers receiving citalopram detected a higher number of facial expressions of fear and happiness, with reduced response times, relative to those given the placebo. By contrast, changes in the recognition of other basic emotions were not observed following citalopram. Notable differences in mood were also not apparent in these volunteers. These results suggest that acute administration of antidepressant drugs may affect neural processes involved in the processing of social information. This effect may represent an early acute effect of SSRIs on social and emotional processing that is relevant to their therapeutic actions. (+info)