P.1.057 Characterization of the serotonin transporterand its modulation by antidepressants in peripheral blood lymphocytes

PT, Affeetioe disorders and ant~depressauts psychopharmacological profile of this compound. We conducted a set of the basic screening tests (open fold test, plus maze test, forced swimming test and passive avoidance test) to accomplish this. The experiments were performed on male Wistar rats weighting 180-200 g. The drug was injected intraperitoneally in doses of 10 and 50 mg/kg 1 hour before the test sessions. Administrated doses were equal to 1/300 (10 mg/kg) and 1/80 (50 mg/kg) of the LD50. All behavioral tests were performed according standard protocols. We have not observed any significant changes in rat behavior in the open field, plus maze and passive avoidance tests. We revealed decrease in time of immobilization (no movements of rat paws in the water) in the forced swimming test after VMA99-82 administration in comparison with control group. The periods &immobilization in the rats received VMA-99-82 in dose of 10 mg/kg and 50 mg/kg were reduced significantly to 18.24-5.7 s and 26.34-5.4 s, respectively, in comparison with control time of immobilization 62.34-8.5 s (p<0.05, one way ANOVA and Bonferroni post hoc test). We have not observed increase in rats locomotor activity in the open field test. Thus, the reduction of immobility time in the forced swimming teat has been caused rather by antidepressant activity than psychostimulatory effect of the investigated drug. The results obtained in the present study demonstrate the antidepressant-like effect of the new adenine derivative in the forced swimming test.

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Modafinil combined with selective serotonin reuptake inhibitor at treatment initiation enhances the rate and degree of benefit in major depressive disorder

H.A. Haasman 1, S.J. Glass 1, A. Sciamanna 1, P.T. Ninan 2, 1CNS

t~esearc~ f~stitute, PC,, nla, C2ementon, New Jersey, US~A,; 2Emery University School of Medicine, Mood and Anxiety Disorders 2rogram, A#antc~ G~orgia, US.A. Objective: Selective serotonin reuptake inhibitor (SSRI) treatment response in depression typically takes several weeks, with only a modest proportion of patients achieving rapid response or remission. For example, the response at 6 weeks to the SSRI fluoxetine is approximately 50% [1], and patients may still exhibit residual symptoms such as fatigue [2]. The novel wakepromoting drug modafinil has been shown to reduce symptoms of fatigue in depressed patients with an incomplete response to SSRI therapy [3]. We conducted this open-label study to examine the speed of onset, efficacy, and safety of modafinil combined with fluoxetine or paroxetine at treatment initiation on depression and fatigue symptoms in patients with mNor depressive disorder and significant fatigue. Methods: Patients free from antidepressant therapy for at least 4 weeks were enrolled and started on a combination of modafinil and SSRI therapy. Modafinil was initiated (100 my/day titrated to 200 my/day) with fluoxetine or paroxetine 20 my/day for 6 weeks. Assessments included the Hamilton Rating Scale for Deprezsion (I-IAMD) and Fatigue Severity Scale (FSS). The percentage of patients achieving remission (defined as a score of ~<7 in HAMD21 at any postbaseline visit) was also analyzed. Results: 23 of 29 evalnable patients (79%) completed the study. Modafinil combined with an SSRI significantly improved depression symptoms at week 1 (mean change [5Z)] in NAMD31 from baseline -9.3 [9.7]; p<0.01), and this improvement was progressive to week 6 (mean change in HAMD-31 from baseline -21.2 [11.6]; p<0.01). Adjunct modafinil rapidly and significantly

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reduced fatigue at week 1 (mean FSS change from baseline -0.7 [1.1]; p<0.01), and this progressed to week 6. Additionally, 39% and 58% of patients were remitters by week 2 and week 6, respectively, after treatment with modafinil and SSRI. The combination treatments were well tolerated. The most common adverse events were nausea (41%; n=12) and headache (24%; n=7). Concision: Modafinil combined with an SSRI at initiation may enhance the rate and degree of SSRI benefit in patients with depression and fatigue. Source of Fui~ling: CepMlon, Inc., West Chester, PA

References [1] Nierenberg A.A., etal. (2001) Definitions of antidepressant treatment response~ remission, nonresponsE partial response and other relevant outcomes: a focus on treamlent-resistant depression. J Clin Psychiatry. 62 (Suppl 16), 5-9. [2] Zajeoka, J.M. (2000) Clinical issues in long-term treatment with antidepressants. J Clln Psy&iatry. 61 (Suppl 2), 20-25. [3] Marlcovitz,P.J. and Wagner, S. (2003) An open-label trial of modafinil augmentation in patients with partial response to antidepressant therapy. J Clin Psy&opharmaool. 23, 207-209.

~Characterization

of the serotonin transporter and its modulation by antidepressants in peripheral blood lymphoeytes

T. Barkan 1, I). Gutwitz 1, A. Weizman 2, M. Rehavi 1 . 1TelAoio U~ioersity Saekler Yaeu#y of Medicine, P~ysiology and PJ~armacology, Tel-Aviv, Israel; 2Tel-Aoio University Sac;rler Faculty of Medicine, C~t~a Psychiatric i-iospita4 Peta~ Tikva, Israel The serotonin (5-I4T) transporter (5-I4TT) plays a critical role in the termination of serotonin neurotransmisaion and represents the prime target %r selective serotonin reuptake inhibitom (SSRIs), Human peripheral blood lymphooytes possess a high affinity transport system %r 5-HT, The identification of a reliable peripheral marker %r brain 5-KTT and the regulation of its expression in easily accessible cells such as blood lymphooyt~ could contribute to the understanding of neuropsyohiatrio and addictive disorders and their treatment. Recently we have demonstrated that the characteristics of the 5-1-1TT in human lymphocytes are similar to those of the 5-NTT in neuronal tissues and in blood platelets (Barkan et al., In Press). In the present study the serotonin transporter protein was further characterized by high affinity [3I-I]citalopram binding. Furthermore, we confirmed the expression of plasma membrane 5-HTT in human peripheral blood lymphocytes by means of Western immunoblotting. We assessed the regulatory effect of tricyclic antidepressants and SSRI antidepressants on the 5-HTT expression using [3H]citalopram binding. MethocN: Fresh lyrnphocytes were isolated from blood by Ficell Gradient centriNgation. The fresh lymphocytes were assayed for either [3I-I]5-NT uptake, [3N]citalopram binding or 5-I-ITT expression using Western immunoblotting. For regulation studies of the 5-KTT, fresh lymphocytes were resuapended in RPMI medium containing varying concentrations of the teated drugs and incubated for 24 or 48 hours. Expression levels of 5-I-ITT were assayed using [3H]citalopram binding. Results: The specific binding of [3t-I]citalopram to membranes from lymphocytes was found to be saturable and of high affinity. Scatchard analysis of the equilibrium binding data revealed a single class of noninteracting binding sites with an apparent

PI, Affectioe di~ov&rs and ant~cle.pre~sa~t~

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equilibrium dissociation constant (Kd) of 3.4 nM and a t;max of 919 fmol/mg protein. The uptake of [3H]5-t-IT by human lymphocytes was concentration-dependent, with characteristics of saturable kinetics. Lineweaver-t)urk anal~is yielded a km of 370 nM and V ~ of 2059 fmol/min/105 cells. Immunoblot analysis showed a single band of approximately 70 kDa for rat brain striatum as well as for human lymphocytes and lymphoblasts. A significant decrease in [3H]citalopram binding is observed upon incubation of lymphocytes for 24 or 48 hours in the presence of 10-r M tricydic antidepressants or SSRIs. A profound increase in [3H]citalopram binding is detected upon incubation for the same periods of time in the presence of 10-~ and 10.5 M of the same drugs. C o n e l ~ i o m This study demonstrates that human lyrnphocytes possess a high affinity transport system for 5-HT, with general characteristics and pharmaooldnetic properties which are similar to those of the 5-I-ITT in neuronal tissues and in blood platelets. The expression of the 5-HTT in human peripheral blood lyrrphooytes is modulated upon exposure to different concentration of various antidepressant drugs. These findings might help understand the regulatory action and different efficacies of antidepressant drugs.

References [1] Barkan T, Gurwitz D., Levy O., Weizman A., Rehavi M. Bioohemieal and pharmacological characterizationof the serotonin transporterin human peripheralblood lymphoeytes, European Neuropsyohopharmaoology, In Press

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[3t-1]monoamines from the tissue to the medium was determined by measurement of radioactivity. Restflts: Exposure of preloaded brain slices to hyperforin induced small though dose dependent release (2 * 10-hM - 2" 10-CM) of both [3I-I]dopamine and [31-I]serotonin. Depolarization with 25mlv2 KC1 (for dopamine) and 50ram (for serotonin) induced dramatic release of the preloaded monoamines. The K + stimulated release of the monoamines was dose dependently attenuated by 15 rain preincubation with hyperforin. The reduction in K + stimulated release of the [3t-I]monoamines correlated with the duration of the preincubation with hypefforin; longer exposure periods yielded lower values of K + evoked release of the monoamines. Incubation of the brain slices with reserpine before the 'qoading" with radiolabeled monoamines was associated with a dose dependent blunting of release due to hyperforin. Amphetamine induced release of [3t-1]dopamine and fenfiuramine induced release of [3I-I]serotonin was higher (23% and 32% respectively) after exposure of the brain slices to hyperforin (4" 10-~M). The increased amphetamine and fenfluramine induced release of the [3t-1]monoamines correlated with the incubation time with hyperforin. Coilel~ioxlS: The data presented in this report support the assumption that hyperforin collapses the transvesiclular pH gradient inducing a redistribution of the monoamines from the vesicular to the cytoplasmic pool. The increased brain levels of dopamine and serotonin following hyperforin or St. John's weft extract administration may be the consequence of their cytoplasmic accumulation.

• HyperforJn induces release of dopamine and serotonin from rat brain slices

IVi. lkehavi, N, Roz, 7"el-Aoio Unioersi~ gackler Facu#y of

Medicine, Dhyxiology and Pharmacolo~, Tel-Aoio, Israel t-lyperforin, found in t-lypericum perforatum (St, John's wort) extracts has antidepressant properties, I-lyperforin has a unique pharmacological profile and it inhibits uptake ofbiogenic monoamines as wall as amino acid transmitters. We have recently showed that the monoamines uptake inhibition exerted by hyperforin is related to its ability to dissipate the pK gradient across the synaptic vesicle membrane thereby interfering with vesicular monoamines storage. In this study we demonstrate that hyperforin induces dose dependent release of preloaded [~H]5I-IT and [3I-I]DA from rat brain slices. We show that hyperforin attenuates depolarization dependent release of monoamines, while increasing monoamine release by amphetamine or fenfiuramine. We demonstrate that preincubation of brain slices with reserpine is associated with dose dependent blunting of release due to hyperforin. Our data indicate that hyperforin induced release of [3H]5HT and [3H]DA refieot elevated cytoplasmic concentration of the two monoamines secondary to the depletion of the synaptic vesicle content and the compartmental redistribution of nerve ending monoamines. [3I-I]monoamines release: Rat brain cortical slices were incubated with 5"10-8M [3I-I]dopamine or [3I-I]serotonin in the presence of 10~Ivi paegyline for 30 rain. The washed slices were placed in baskets with a mesh bottom. Each basket was transferred at 1 rain intervals through a series of vials containing buffer until stabilization of basal [3I-I]monoamine release. For stimulated release, the baskets were transferred to vials containing different stimulators (25mM or 50mM KC1 for 1 rain, 10btM amphetamine for 5 min, 10~M fenfluramine for 5 rain). The rate of release of

Subacute effects of sertraline on attentional and executive functions in major depression

E,L, Constant j , S, Adam 2, B, Qillain j , X, Geron 3, R, Bruyer 3, A, Seghers 1, 1Unioerxit~ Catholique de Youoain, P~yohiatry,

Bru;celle4 Belgium; 2 University of Li@e, NeuropsyeAology Unit, Li@e, Bel~um; 3 Unioersit~ Catholique de Louoain, Cognitioe Neurosoienee Unit, Louoain-la-Neuoe, Belgium

P~-'pose: Several cognitive dysfunctions in depression have been documented in the literatur% concerning attention,executive functions or memory, Several authors have demonstrated difficulties of inhibition during czecutiv¢ tasks, with material of negative emotional valence, I-Iowever~ divergences concerning the severity and reuersibility of cognitive disturbances exist in the literature due to methodological bias (sensitivity of the tests, age of the patients, heterogeneity of the depressive pathologies), l~Ielheds: By using a precise methodology, this study examines attention and caecutive functions in 20 relatively young depressed patients (mean age, 4"],65 yr), presenting a first or second episode of major unipolar depression, all given the same psychopharmacological treatment (sertraline 50 to 75 my/day) in order to investigate the changes in potential attentional and executive loss during a subacute period of treatment of 7 weeks, We compared their performance with that of a group of 26 control suNeots matched %r age and sociocultural level, The cognitive battery (phasic alertness task, classic Stroop test,supraliminal and subliminal emotional Stroop test) took place the firsttime before antidepressant treatment, the second one 3 weeks later and finally the third one W weeks after the first one, Affeetive symptoms were assessed with the self-rated Beck Depression Inventory (BDI) and anxiety syrnptome with the STAI state/traitscale, For statistical analysis, 2 way ANOVAs (Beck Depression Inventory, STAI), 3 way AN©VAs (phasic alertness, classic Stroop, supra-