Dopamine transporter binding in females with panic disorder may vary with clinical status

Background

To date the involvement of dopamine system in neurobiology of panic disorder (PD) has been not investigated by imaging studies in humans. In this study, we evaluated the binding potential of dopamine transporter (DAT) in striatum of patients with PD.

Methods

Subjects comprised seven female patients with current PD, seven female PD patients in remission and seven female healthy controls, matched by age. Striatal DAT binding was evaluated using single-photon emission computed tomography and [¹²³I]nor-β-CIT tracer.

Results

Significantly higher DAT binding in striatum was detected in remitted PD females as compared with both currently ill PD and control females. The females with current PD demonstrated non-significant lowering in striatal DAT binding as compared with healthy controls. The correlation analysis in total sample of female patients showed significant and inverse relationship between striatal DAT binding characteristics and severity of panic symptoms.

Conclusions

This is first report showing that DAT binding in striatum may depend on the clinical status in females with PD. Our data suggest that increased level of DAT may contribute to stability of remission; however, the exact involvement of dopamine system in PD pathogenesis requires further investigations. The preliminary results of current study should be confirmed by other independent studies and should also be extended to include male patients.     

Availability of the serotonin transporter in patients with alcohol dependence

Abstract

Objectives. Evidence has suggested that the serotonin transporter (SERT) plays a role in the pathogenesis of alcohol dependence, anxiety and depression and that polymorphisms of the serotonin-transporter-linked promoter region (5-HTTLPR) may influence the SERT. This study evaluated the differences in SERT availability between healthy controls and alcoholic patients and the impact of 5-HTTLPR polymorphisms on SERT availability. Methods. Eleven healthy controls and 28 alcoholic patients were recruited. SERT availability was measured in vivo with single photon emission computed tomography and ¹²³I-labelled 2-((2-((dimethyl-amino)methyl)phenyl)thio)-5-iodophenylamine in the midbrain, thalamus and striatum. Each subject was genotyped for the 5-HTTLPR polymorphism. Results. Compared to healthy controls, there was a significantly lower availability of SERT in the midbrain among patients with pure alcohol dependence (pure ALC). Of patients with anxiety, depression and alcohol dependence (ANX/DEPALC), the carriers of one L_A allele showed a significantly higher availability of SERT in the striatum compared to non-L_A carriers. After Bonferroni correction, these significances vanished. There were no significant differences in SERT availability between controls and ANX/DEP ALC. Conclusions. The results suggest that pure alcoholics may have lower SERT availability in the midbrain; the 5HTTLPR polymorphism may influence SERT availability in ANX/DEP ALC. These findings may serve as a springboard for future large-scale studies.     

Decreased brain serotonin transporter binding in the euthymic state of bipolar I but not bipolar II disorder: a SPECT study

Chou Y‐H, Wang S‐J, Lin C‐L, Mao W‐C, Lee S‐M, Liao M‐H. Decreased brain serotonin transporter binding in the euthymic state of bipolar I but not bipolar II disorder: a SPECT study.
Bipolar Disord 2010: 12: 312–318. © 2010 The Authors.
Journal compilation © 2010 John Wiley & Sons A/S. Objectives: Previous positron emission tomography studies have demonstrated that serotonin transporter (SERT) binding in the midbrain is decreased in the depressive state of bipolar disorder (BD). The aim of this study was to assess SERT binding in the midbrain of patients in a euthymic state of BD. Methods: Twenty‐eight healthy controls and 24 patients in a euthymic state of medicated BD were recruited. Euthymic state was defined as Montgomery‐Åsberg Depression Rating Scale scores < 10 and Young Mania Rating Scale scores < 7 within a consecutive eight‐week period. Single photon emission computed tomography with the radiotracer ¹²³I‐ADAM was used to measure SERT binding in the midbrain. An equilibrium ratio model was used for data analysis. Specific uptake ratio (SUR), which represents availability of SERT binding in the midbrain, was the primary measurement outcome. Results: The averaged SURs were not different between healthy controls and BD patients in euthymic state (p = 0.27). However, a three‐way ANCOVA analysis comparing SURs in healthy controls, bipolar I disorder (BD I) patients, and bipolar II disorder (BD II) patients, covarying education duration and sex, showed that the averaged SURs were significantly lower in BD I than BD II patients and healthy controls (p = 0.042). The decreased SURs in BD I patients were well correlated with duration of illness (R = ?0.742, p = 0.014) only. Conclusions: Our findings demonstrate that there is differential biological regulation in BD I and BD II patients after stable treatment, which may support the existence of a dichotomy in BD.     

Elevated serotonin transporter binding in major depressive disorder assessed using positron emission tomography and [11C]DASB; comparison with bipolar disorder.

BACKGROUND: Altered serotonergic function is thought to play a role in the pathophysiology of major depressive episodes based upon evidence from neuroimaging, pharmacological, postmortem and genetic studies. It remains unclear, however, whether depressed samples that differ with respect to having shown a unipolar versus a bipolar illness course also would show distinct patterns of abnormalities within the serotonergic system. The current study compared serotonin transporter (5-HTT) binding between unipolar-depressives (MDD), bipolar-depressives (BD) and healthy-controls (HC) to assess whether the abnormalities in 5-HTT binding recently found in depressed subjects with BD extend to depressed subjects with MDD. METHODS: The 5-HTT binding-potential (BP) measured using positron emission tomography (PET) and [(11)C]DASB was compared between unmedicated, depressed subjects with MDD (n = 18) or BD (n = 18) and HC (n = 34). RESULTS: Relative to the healthy group both MDD and BD groups showed significantly increased 5-HTT BP in the thalamus (24%, 14%, respectively), insula (15%) and striatum (12%). The unipolar-depressives had elevated 5-HTT BP relative to both BD and HC groups in the vicinity of the periaqueductal gray (PAG, 20%, 22%, respectively). The bipolar-depressives had reduced 5-HTT BP relative to both HC and MDD groups in the vicinity of the pontine raphe nuclei. Depression-severity correlated negatively with 5-HTT BP in the thalamus in MDD-subjects. CONCLUSIONS: The depressed phases of MDD and BD both were associated with elevated 5-HTT binding in the insula, thalamus and striatum, but showed distinct abnormalities in the brainstem. The latter findings conceivably could underlie differences in the patterns of illness symptoms and pharmacological sensitivity observed between MDD and BD.     

5-羟色胺转运体基因第二内含子多态性与强迫症的关联分析

目的　探索上海地区汉族人口中 5 羟色胺转运体 ( 5 HTT)基因第二内含子多态性与强迫症的关系。方法　采用聚合酶链反应扩增片段长度多态 (PCR AmFLP)技术测定 10 2例强迫症 (OCD)患者和 110名健康对照的基因型。结果　强迫症患者 5 HTT第二内含子基因型与等位基因分布与健康对照之间均存在显著性差异 (P <0 0 5 ) ;等位基因 10和 12 / 10基因型与强迫症存在显著正关联 (OR值分别为 2 4 5和 2 4 2 ,P <0 0 5 )。结论　汉族人群中 5 HTT基因第二内含子多态性与强迫症的发病可能有遗传关联 ,等位基因 10和 12 / 10基因型可能是强迫症的风险因子     

强迫症与5-羟色胺转运体基因多态的关联分析

目的 探索汉族人群中5-羟色胺转运体SLC6A4基因多态与强迫症发病的关系。方法采用聚合酶链反应扩增片段长度多态技术测定120例强迫症患者(强迫症组)和130名健康人(对照组)的SLC6A4基因型。结果 强迫症组SLC6A4第2内含子及启动子的基因型多态分布与对照组间的差异有显著性(X2=6.70,P=0.035;X2=6.35,P=0.042);第2内含子等位基因频数分布与对照组之间的差异有非常显著性(X2=7.54,P=0.006);第2内含子的等位基因10,12/10基因型和启动子的L/L基因型与强迫症存在显著正关联[比数比(OR)值分别为2.24,2.12和3.57,P<0.05];强迫症组及对照组内不同性别间基因型分布的差异均无显著性(P>0.05)。结论 在汉族人群中SLC6A4基因可能与强迫症存在遗传关联,第2内含子的等位基因10和12/10基因型、启动子的L/L基因型可能是强迫症的风险因子。     

Changes in midbrain serotonin transporter availability in atypically depressed subjects after one year of psychotherapy

BACKGROUND: Psychotherapy is an effective treatment method for depression, but no differences in the psychotherapy response have been found between the subtypes of depression. The effect of psychotherapy on neurotransmitter transporter functions has never been recorded in depressed subjects. METHODS: Depressive outpatients (N=19) received psychodynamic psychotherapy for 12 months. All subjects fulfilled the DSM-IV criteria for depression, and 8 were classified as having atypical depression. The severity of depression was assessed with the 29-item Hamilton Depression Rating Scale (HAM-D-29). Midbrain serotonin transporter (SERT) and striatum dopamine transporter (DAT) densities were recorded using single photon emission computed tomography (SPECT) brain imaging with the [123I]nor-beta-CIT radioligand before and after psychotherapy. RESULTS: Midbrain SERT density significantly increased during psychotherapy in atypicals but not in nonatypicals. There were no changes in the levels of DAT. CONCLUSIONS: The psychotherapy-related SERT elevation of atypically depressed subjects may be due to some unknown adaptive mechanisms inducing an increase in either the levels of SERT or serotonergic nerve terminals and therefore enhancing serotonergic activity and improving mood.     

强迫症伴强迫型人格障碍患者的临床表现

目的 评估强迫型人格障碍（OCPD）在强迫症（OCD）中的发病率,探讨伴OCPD的OCD患者的临床特征.方法 采用DSM-Ⅳ人格障碍临床定式检测手册（SCID-Ⅱ）中有关OCPD的诊断项目对260例OCD患者进行评估,据其是否符合OCPD诊断而将患者分为共病组（OCD＋ OCPD）和非共病组（OCD-OCPD）.对两者的临床特征、焦虑、抑郁水平等进行比较.结果 78例（30％）OCD患者符合OCPD的诊断;共病组有更多的物品污染、囤积以及高道德标准强迫思维和更多的检查、囤积和混合强迫行为等强迫症状,且共病组强迫行为严重程度、抑郁及特质焦虑水平显著高于非共病组,但两组首次出现强迫症状的年龄,有精神疾病家族史的比例以及自知力水平、状态焦虑水平等差异无统计学意义.结论 强迫型人格障碍与强迫症的重叠可能增加了其病理心理的严重程度.     

Serotonin transporters in obsessive-compulsive disorder: a positron emission tomography study with [(11)C]McN 5652.

BACKGROUND: Serotonergic abnormalities have been hypothesized to contribute to obsessive-compulsive disorder (OCD). This study examined whether brain serotonin transporter (SERT) availability is altered in OCD using positron emission tomography (PET) and the SERT PET radiotracer [(11)C]McN 5652. METHODS: Eleven OCD subjects, free of psychiatric medications and comorbid depression, and 11 matched healthy control subjects underwent PET scans following injection of [(11)C]McN 5652 and magnetic resonance imaging (MRI) scans. Total distribution volumes (V(T)) were derived by kinetic analysis (one tissue compartment model) using the arterial input function. Two measures of SERT availability were computed: binding potential (BP) and specific to nonspecific partition coefficient (V(3)"). Groups were compared using region of interest (ROI) analysis and voxelwise analysis of spatially normalized parametric maps; ROIs were selected based on their relatively high SERT density and included subcortical (dorsal caudate, dorsal putamen, ventral striatum, midbrain, thalamus) and limbic (hippocampus, amygdala, anterior cingulate cortex) regions. RESULTS: No significant group differences were observed in [(11)C]McN 5652 BP or V(3)" in the ROIs. No significant group differences were detected in the voxelwise analysis of BP or V(3)" maps. CONCLUSIONS: OCD without comorbid depression, may not be associated with major changes in SERT availability in subcortical and limbic regions.     

Reduced midbrain-pons serotonin transporter binding in patients with obsessive-compulsive disorder

OBJECTIVE: To evaluate current hypothesis regarding the pathophysiology of obsessive-compulsive disorder (OCD) by studying the serotonin receptor binding in patients with OCD using single photon emission computerized tomography (SPECT). METHOD: We studied nine patients (four men and five women, age range 21-56 years) fulfilling the DMS-III-R criteria for OCD using SPECT and the serotonin transporter (SERT) tracer (123)I-beta-CIT. SERT binding potential (BP2) was determined by Logan plot derived from seven scans obtained during 10-400 min. RESULTS: The binding of (123)I-beta-CIT in midbrain-pons was reduced in OCD patients when compared with controls (BP2 0.97 +/- 0.07 vs. 0.84 +/- 0.12, P = 0.011). There was no correlation between BP2 and any of the clinical variables (age at onset, disease duration, and Yale-Brown Obsessive-Compulsive Scale score). CONCLUSION: This study suggests a reduced serotonergic input into the fronto-subcortical circuits in OCD, thereby diminishing the inhibitory regulation of serotonin on these circuits.     

Sex differences in diencephalon serotonin transporter availability in major depression.

BACKGROUND: Major depression is more prevalent in women than men. The present study evaluated if previous findings that demonstrated decreased 5-hydroxytryptamine (5-HT) transporter availability in depressed patients would be confirmed in a larger sample and also evaluated sex differences. METHODS: Depressed (n = 32) and healthy subjects (n = 32), including 16 pairs of women and men, participated in an iodine-123-2 beta-carbomethoxy-3beta-(4-iodophenyltropane) ([(123)I]beta-CIT) single photon emission computed tomography (SPECT) and a magnetic resonance imaging (MRI) scan. Participants were administered [(123)I]beta-CIT (225.7 +/- 3.7 MBq) and imaged 23.0 +/- 1.6 hours later. Statistical analyses included analysis of variance and a regression analysis of the main and interactive effects of age, sex, and depression. RESULTS: Overall, depressed patients demonstrated 12% lower diencephalon and no change in striatal or brainstem [(123)I]beta-CIT uptake. Significant age by sex, sex by depression, and age by sex by depression interactions were noted due to 22% lower diencephalon [(123)I]beta-CIT uptake in depressed women compared with less than a 1% decrease in depressed men. CONCLUSIONS: As observed previously, diencephalon 5-HT transporter availability is decreased in depressed patients. However, the decrease appears to be sex-specific and age-dependent. These findings suggest that serotonergic mechanisms mediating depressed mood differ between men and women in an age-dependent manner and may explain why young women respond better to treatment with selective serotonin reuptake inhibitor (SSRI) antidepressants.     

Relationship between neuroticism personality trait and serotonin transporter binding.

BACKGROUND: Personality trait is thought to be one of the important factors for vulnerability to depression. The relation between serotonin transporter (5-HTT) polymorphism and anxiety-related personality has been investigated in genetic research. In this study, we investigated the relation between in vivo regional 5-HTT binding in the brain and personality inventory measures in normal male volunteers. METHODS: Thirty-one healthy male volunteers underwent positron emission tomography scans with (11)C-labeled 3-amino-4-(2-dimethylaminomethyl-phenylsulfanyl) benzonitrile ([(11)C]DASB) to measure 5-HTT and completed revised NEO Personality Inventory. Correlation of [(11)C]DASB binding potentials (BP) with personality inventory measures was calculated using region-of-interest analysis and statistical parametric mapping based on the BP images. RESULTS: Neuroticism was positively correlated with 5-HTT binding in the thalamus (p = .004). No significant correlation was observed in any other brain region. Within the neuroticism dimension, the facet of depression was positively correlated with 5-HTT binding in the thalamus (p = .001). CONCLUSIONS: Subjects with higher thalamic 5-HTT binding are more likely to express higher levels of neuroticism and depressive feeling. Serotonin transporter binding in the thalamus might be a marker of vulnerability to depression.     

Effects of tryptophan depletion on the serotonin transporter in healthy humans.

BACKGROUND: Lowering of brain serotonin by acute tryptophan depletion (TD) frequently leads to transient symptoms of depression in vulnerable individuals but not in euthymic healthy subjects with a negative family history of depression. The effects of TD on regional serotonin transporter binding potential (5-HTT BP), an index of 5-HTT density and affinity, were studied in healthy individuals using 3-(11)C-amino-4-(2-dimethylaminomethylphenylsulfanyl)benzonitrile ([11C]DASB) positron emission tomography (PET). Adaptive decreases in 5-HTT density and/or affinity during TD would be a possible compensatory mechanism to maintain sufficient extracellular serotonin levels during TD, thereby preventing a depressive relapse. METHODS: Regional noninvasive 5-HTT BP was found in 25 healthy subjects using [11C]DASB PET. Fourteen subjects were scanned twice, once after TD and once after sham depletion, and 11 other healthy subjects were scanned twice to measure test-retest reliability of the method. RESULTS: None of the healthy subjects experienced depressive symptoms during TD and there was no difference in regional 5-HTT BP during TD as compared with sham depletion. CONCLUSIONS: Acute changes in 5-HTT density or affinity are unlikely to play a role in protecting healthy subjects against mood symptoms during TD. Other mechanisms that may be associated with greater resilience against acute lowering of extracellular serotonin should be explored to gain further insight into the neurochemical basis of different vulnerabilities to short-term depressive relapse.     

5-羟色胺转运体基因启动子区域多态性与汉族强迫症的关联分析

目的探讨5-羟色胺转运体（Serotonin transporter,5-HTT）基因SLC6A4（solute car-rier family6,member4）启动子区域上44个碱基对插入/缺失多态性与汉族强迫症的关系,研究强迫症病理生理机制。方法将符合《疾病及有关健康问题的国际分类》（第10版,ICD-10）诊断标准的23例强迫症患者,及其父母纳入研究。用PCR法检测判定各自的基因型,用传递不平衡检测（transmission disequilibriumtest,TDT）及单体型相对风险检测（haplotype-based haplotype relative risk,HHRR）测其等位基因的传递是否平衡。结果在所收23个核心家系中,共有24个父母为杂和基因型,在24个杂合子父母中,13个传递了‘l’等位基因,11个传递了‘s’等位基因,未发现有传递不平衡存在（χ^2 DT=0.167,P〉0.05;χ^2HRR=0.820,P〉0.05）。结论5-羟色胺转运体基因启动子区域多态性与中国汉族强迫症可能不存在关联。     

Cellular localization and expression of the serotonin transporter in mouse brain

The high-affinity serotonin (5-HT) transporter (5-HTT) plays an important role in the removal of extracellular serotonin, thereby modulating and terminating the action of this neurotransmitter at various pre- and post-synaptic serotonergic receptors and heteroreceptors. In order to characterize the anatomical distribution of the 5-HTT in mouse brain, in situ hybridization histochemistry using ³⁵S-labeled riboprobes was performed. These results were compared with 5-HTT binding site distribution as evaluated by [¹²⁵I]RTI-55 autoradiography. High levels of 5-HTT mRNA were detected in all brain stem raphe nuclei, with variations in labeling among the various subnuclei. Those brain areas known to possess serotonergic cell bodies stained intensely for both 5-HTT mRNA and 5-HTT binding sites. In contrast to previous findings in rat brain, the highest densities of 5-HTT sites were found in areas outside the raphe complex, particularly in the substantia nigra, globus pallidus, and superior colliculi.     

Brain serotonin transporter availability predicts treatment response to selective serotonin reuptake inhibitors.

BACKGROUND: Few studies have investigated the predictive value of central serotonin transporter (SERT) availability for treatment response to serotonin reuptake inhibitors (SSRIs). This study used brain imaging to examine the relationship between pretreatment brain SERT availability and transporter occupancy by SSRIs with treatment response in two independent depressed populations. METHODS: Study 1: Twenty-three patients with major depression underwent a single photon emission computed tomography (SPECT) measurement of brain SERT availability using [123I]beta-CIT ([123I]methyl 3beta-(4-iodophenyl) tropane-2beta-carboxylate. The SERT availability was correlated with treatment response to fluoxetine (20 mg/day) assessed with weekly Hamilton Depression Rating Scale (HDRS) for 6 weeks. Study 2: The second group included 10 depressed patients who received 6 weeks of paroxetine treatment (20 mg/day) and serial SPECT scans (baseline, during, and after the treatment). RESULTS: In Study 1, higher pretreatment diencephalic SERT availability significantly predicted better treatment response 4 weeks later. Similar results were found in Study 2 and supported Study 1 findings. The data showed that greater occupancy of diencephalic transporters by paroxetine correlated with better treatment response. CONCLUSIONS: Higher pretreatment availability and greater occupancy of SERT in diencephalon may predict better treatment course in response to SSRIs.     

Serotonin transporter availability in patients with schizophrenia: a positron emission tomography imaging study with [11C]DASB.

BACKGROUND: Postmortem studies have reported several alterations in serotonin transporter (SERT) binding parameters in patients with schizophrenia. The aim of this study was to compare SERT availability in vivo in patients with schizophrenia and matched control subjects. METHODS: Ten medication-free patients with schizophrenia and 10 healthy subjects underwent positron emission tomography (PET) scans for 90 min after 11C-3-amino-4-(2-dimethylaminomethylphenylthio)benzonitrile ([11C]DASB) injection. Metabolite-corrected arterial input function was measured. Regional distribution volumes (mL/g) were derived with a two tissue compartment kinetic model. Outcome measures for SERT availability included binding potential (BP) and the specific-to-nonspecific equilibrium partition coefficient (V3'). Ten brain regions with high density of SERT and where SERT availability can be reliably quantified with [11C]DASB were included in the analysis. RESULTS: No significant differences were observed in regional BP or V3' between patients and control subjects. No significant relationships were observed between regional SERT availability and severity of positive, negative, and depressive symptoms. CONCLUSIONS: This study failed to detect alterations of SERT availability in patients with schizophrenia; however, this study does not rule out the possibility that schizophrenia might be associated with alterations of SERT density in the cortical regions, where the [11C]DASB-specific binding signal is too low for reliable quantification of SERT.     

The degree of depression in Hamilton rating scale is correlated with the density of presynaptic serotonin transporters in 23 patients with Wilson's disease

Objective: One of the most frequent psychiatric symptoms in patients with Wilson's disease (WD) is depression. It has been suggested that depression is associated with deficits in serotonergic neurotransmission, but, hitherto, no measurements have been performed in WD. Methods: We prospectively examined 23 adult patients (12 women, 11 men, mean age 40 years) with WD for symptoms of depression using the Hamilton rating scale for depression (HAMD). We correlated the data with the presynaptic serotonin transporter density (SERT density) in the thalamus–hypothalamus and the midbrain–pons regions measured with high resolution single-photon emission computed tomography (SPECT) 24 hours after the application of 180 MBq 2β-carbomethoxy-3β-(4 [¹²³I]iodophenyl)tropane ( [¹²³I]b-CIT). The regions of interest were determined by coregistration with a standard MRI dataset. Results: A significant negative correlation was found between HAMD and SERT density in the thalamus–hypothalamus region (r = −0.49, p = 0.02), but not in the midbrain–pons (r = −0.31, p = 0.15). Conclusions: We conclude that depression in patients with Wilson's disease is correlated with alterations of serotonergic neurotransmission in the thalamus–hypothalamus region. Received: 24 July 2002, Received in revised form: 20 November 2002, Accepted: 28 November 2002 Correspondence to Wieland Hermanns, MD     

强迫症患者局部脑血流灌注研究

目的　探讨强迫症(OCD)患者局部脑血流灌注(rCBF)特点及临床症状与rCBF的关系。方法　对2 8例符合国际疾病分类第1 0版(ICD 1 0 )强迫障碍诊断标准患者和1 5名正常人进行单光子发射计算机断层扫描(SPECT)脑显像分析。用耶鲁 布朗强迫评定量表(YBOCS)、Hamilton焦虑量表(HAMA)和Hamilton抑郁量表(HAMD)对患者临床症状进行评定。结果　OCD患者两侧丘脑、顶叶和基底神经节的平均放射性计数百分数(PMRC)显著高于正常组;右颞PMRC明显低于正常组;且正常组两侧颞叶和顶叶PMRC值差异非常显著。在强迫恐惧/洗涤、回避组,YBOCS强迫行为分量表评分与右基底PMRC显著正相关(r =0 .70 1 )。结论　OCD患者两侧丘脑、顶叶和基底神经节的血流灌注增加和功能亢进;右颞血流灌注减少和功能低下,两侧颞叶和顶叶血流灌注的不对称性与正常人显著不同,后者的不对称性非常显著;在强迫恐惧/洗涤、回避组,强迫行为与右基底节功能增强有关。