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The efflux pump P-glycoprotein (P-gp), a gene product of the ABCB1 gene, plays a pivotal role in the transfer of various molecules across the blood-brain barrier. P-gp protects the brain by selectively extruding its substrates, including certain antidepressive drugs, thereby limiting their uptake into the brain. Uhr et al. [2008] first showed that ABCB1 variants predicted the remission to antidepressants with P-gp substrate properties in patients suffering from major depression (MD). Other studies investigating the influence of ABCB1 polymorphisms on antidepressant treatment response produced inconclusive results. In this meta-analysis, we systematically summarized 16 pharmacogenetic studies focused on the association of ABCB1 variants and antidepressant treatment outcome in patients with MD (overall n = 2695). We investigated the association of treatment outcome and six ABCB1 single nucleotide polymorphisms (SNPs): rs2032583, rs2235015, rs2235040, rs1045642, rs2032582, rs1128503. We stratified for admission status, ethnicity, and prescription of concomitant medication. SNP rs2032583 showed a nominally significant association across all studies (P = 0.035, SNP was studied in a total of 2,037 patients) and a significant Bonferroni-corrected association among inpatients (P = 1.5 × 10(-05) , n = 485). Also SNP rs2235015 was significantly associated with antidepressant treatment outcome withstanding Bonferroni correction (P = 3.0 × 10(-04) ) among inpatients in a smaller subsample (n = 195). There were no significant associations of the other SNPs tested with antidepressant treatment outcome. Future pharmacogenetic association studies should focus on the role of the ABCB1 SNP rs2032583 in antidepressant outcome prediction., (© 2015 Wiley Periodicals, Inc.)

Early-life stress may lead to persistent changes in central corticotropin-releasing hormone (CRH) and the CRH receptor 1 (CRHR1) system that modulates anxiety-related behavior. However, it remains unknown whether CRH-CRHR1 signaling is involved in early-life stress-induced anxiety-related behavior in adult animals. In the present study, we used conditional forebrain CRHR1 knockout (CRHR1-CKO) mice and examined the potential role of forebrain CRHR1 in the anxiogenic effects of early-life stress. As adults, wild-type mice that received unstable maternal care during the first postnatal week showed reduced body weight gain and increased anxiety levels in the open field test, which were prevented in stressed CRHR1-CKO mice. In the light-dark box test, control CRHR1-CKO mice were less anxious, but early-life stress increased anxiety levels in both wild-type and CRHR1-CKO mice. In the elevated plus maze test, early-life stress had only subtle effects on anxiety-related behavior. Moreover, early-life stress did not alter the basal home cage activity and gene expression levels of key hypothalamic-pituitary-adrenal axis regulators in adult wild-type and CRHR1-CKO mice, but enhanced neuroendocrine reactivity to acute immobilization stress in CRHR1-CKO mice. Our findings highlight the importance of forebrain CRHR1 in modulating some of the anxiogenic effects of early-life stress, and suggest that other neural circuits are also involved in the programming effects of early-life stress on anxiety-related behavior., (© 2012 The Authors. European Journal of Neuroscience © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.)

The majority of genetic risk factors for major depressive disorder (MDD) still await identification. Since copy number variants (CNVs) have been implicated in various neuropsychiatric disorders, the question arises as to whether CNVs also play a role in MDD. We performed a genome-wide CNV study using Illumina's SNP array data from 604 MDD patients and 1,643 controls. Putative CNVs were detected with the CNV algorithms QuantiSNP and PennCNV. CNVs with ≥30 consecutive SNPs and a log Bayes Factor/confidence value of ≥30 were statistically analyzed using PLINK. Further analyses and technical verification were only performed in the case of regions for which CNV calls from both programs showed nominal significance. Set-based tests were used to test whether common variants in the CNV regions showed association in two GWAS datasets of MDD. CNVs from four chromosomal regions were associated with MDD. The following were more frequent in patients than controls: microdeletions in 7p21.3 (P = 0.033) and 18p11.32 (P = 0.030); microduplications in 15q26.3 (P = 0.033); and the combination of microdeletion/duplications in 16p11.2 (P ≤ 0.018). SNPs in CNV region 16p11.2 showed significant association in a set-based test (P = 0.026). Microdeletions/duplications in 16p11.2 are the most promising CNVs, since these affect genes and CNVs in this region have been implicated in other neuropsychiatric disorders. The association finding for common SNPs provides further support for the hypothesis that this region is involved in the development of MDD. © 2012 Wiley Periodicals, Inc., (Copyright © 2012 Wiley Periodicals, Inc.)

Patients suffering from major depression have repeatedly been reported to have dysregulations in hypothalamus-pituitary-adrenal (HPA) axis activity along with deficits in cognitive processes related to hippocampal and prefrontal cortex (PFC) malfunction. Here, we utilized three mouse lines selectively bred for high (HR), intermediate, or low (LR) stress reactivity, determined by the corticosterone response to a psychological stressor, probing the behavioral and functional consequences of increased vs. decreased HPA axis reactivity on the hippocampus and PFC. We assessed performance in hippocampus- and PFC-dependent tasks and determined the volume, basal activity, and neuronal integrity of the hippocampus and PFC using in vivo manganese-enhanced magnetic resonance imaging and proton magnetic resonance spectroscopy. The hippocampal proteomes of HR and LR mice were also compared using two-dimensional gel electrophoresis and mass spectrometry. HR mice were found to have deficits in the performance of hippocampus- and PFC-dependent tests and showed decreased N-acetylaspartate levels in the right dorsal hippocampus and PFC. In addition, the basal activity of the hippocampus, as assessed by manganese-enhanced magnetic resonance imaging, was reduced in HR mice. The three mouse lines, however, did not differ in hippocampal volume. Proteomic analysis identified several proteins that were differentially expressed in HR and LR mice. In accordance with the notion that N-acetylaspartate levels, in part, reflect dysfunctional mitochondrial metabolism, these proteins were found to be involved in energy metabolism pathways. Thus, our results provide further support for the involvement of a dysregulated HPA axis and mitochondrial dysfunction in the etiology and pathophysiology of affective disorders., (© 2012 The Authors. European Journal of Neuroscience © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.)

The High-Throughput Disease-specific target Identification Program (HiTDIP) aimed to study case-control association samples for 18 common diseases. Here we present the results of a follow-up case-control association study of HiTDIP in major depressive disorder (MDD). The HiTDIP in MDD was conducted in a sample of 974 cases of recurrent MDD of white German origin collected at the Max-Planck Institute (MP-GSK) and 968 ethnically matched controls screened for lifetime absence of depression. Six genes were identified as of interest for a follow-up, based on the strength of the association and based on the interest as potential candidate target for developing new treatment for depression: Solute Carrier Family 4 Member 10 (SLC4A10), Dipeptidyl Peptidase IV (DPP4), Dopamine Receptor D3 (DRD3), Zinc Finger Protein 80 (ZNF80), Nitric Oxide Synthase 2A (NOS2A) and Peroxisome Proliferator-Activated Receptor-Gamma, Coactivator 1, Alpha (PPARGC1A). Within the current study, we attempted to follow-up these findings in a sample from the UK, the Depression Case Control (DeCC) sample consisting of 1,196 cases and 842 screened controls, phenotyped using exactly the same methods as the MP-GSK sample. Performing Cochran-Mantel-Haenzel statistics to test for genotypic and/or allelic differences between the DeCC and MP-GSK samples, we found no significant differences, thus being able to combine the two samples for association testing. In the combined sample of 2,170 MDD cases and 1,810 controls, there were positive findings in the Nitric Oxide Synthase 2A (NOS2A) gene both using single SNP analysis and haplotype analysis., (Copyright © 2011 Wiley-Liss, Inc.)

Objectives: Recently, associations of several single-nucleotide polymorphisms (SNPs) within the CLEC16A gene with multiple sclerosis (MS), type-I diabetes, and primary adrenal insufficiency were reported., Methods: We performed linkage disequilibrium (LD) fine mapping with 31 SNPs from this gene, searching for the region of highest association with MS in a German sample consisting of 603 patients and 825 controls., Results: Four SNPs located in intron 19 of the CLEC16A gene were found associated. We could replicate the finding for SNP rs725613 and were able to show for the first time the association of rs2041670, rs2080272 and rs998592 with MS., Conclusion: All described base polymorphisms are mapping to one LD block of approximately 50 kb within intron 19 of the CLEC16A gene, suggesting a pivotal role of this region for susceptibility of MS and possibly also for other autoimmune diseases., (© 2010 John Wiley & Sons A/S.)

Glutamate decarboxylase (GAD) is the rate limiting enzyme for conversion of glutamic acid to gamma-aminobutyric acid (GABA). The GAD 65 kDa isoform is encoded by the gene GAD2 and is mainly expressed in synaptic terminals. It serves as an apoenzyme, which shows enhanced availability in situations of stress, responding to short-term demands for GABA. We analyzed 18 single nucleotide polymorphisms (SNPs) in the GAD2-gene region for associations with psychiatric diagnosis and behavioral inhibition (BI) derived from the personality traits neuroticism and extraversion as defined by the Eysenck Personality Questionaire (EPQ). A total of 268 patients with anxiety disorder (AD), 541 with unipolar depression (MD), and 541 healthy controls were included. We observe associations for five tag-SNPs with BI in the AD- and control samples as well as two additional case-control associations in the MD-sample. The associated SNPs lie within a 16KB linkage disequilibrium-block, including putative 5' GAD2-promoter-elements as well as the 3' end of the gene MYO3A. Using open access mRNA-expression data, we could show that BI-associated SNPs appear to be associated with differences in MYO3A- but not GAD2 lymphoblastoid-mRNA expression levels. These results support earlier studies that suggest associations of polymorphisms within the GAD2 locus with anxiety and affective disorders. However, data from expression studies imply that these polymorphisms could tag functional effects on the neighboring gene MYO3A, which is also expressed in the brain, including the cingulate cortex and the amygdala., (2009 Wiley-Liss, Inc.)

Dispositional coping styles are important moderators of the stress reaction and are altered in stress-related disorders like cardiovascular diseases and affective disorders. Heritability studies suggest a considerable genetic contribution to the interindividual variability in coping styles. Since the angiotensin-converting enzyme (ACE) gene has been described to be associated with the vulnerability for stress-related disorders and with altered stress hormone regulation, we investigated the ACE gene as potential candidate gene for coping styles. Five hundred forty one mentally healthy subjects and 194 patients suffering from depression participating in the Munich Antidepressant Response Signature (MARS) project were examined. Coping styles were assessed with a self-report questionnaire (German Stress Coping Questionnaire SVF78) measuring the individual coping style pattern in response to stressful situations. We genotyped 15 single nucleotide polymorphisms (SNPs) and the insertion/Deletion (I/D)-polymorphism in the ACE gene region and investigated their associations with coping styles. In healthy subjects, the highest association was observed between rs8066276, an intronic SNP of the ACE gene, and the coping factor Distraction. A further intronic SNP rs4305, not in linkage disequilibrium with rs8066276, showed an association with Devaluation/Defense. All associated copying styles can be categorized as potentially stress reducing factors (positive coping). Both SNPs were also found to be associated with positive coping styles in the patient sample; rs8066276 was associated with Devaluation/Defense, and rs4305 showed associations with Control. These results suggest that the ACE gene is involved in the development of coping strategies., (2008 Wiley-Liss, Inc.)

Accumulating evidence from animal studies suggests that the corticotropin releasing hormone (CRH) and arginine vasopressin (AVP) neuropeptide systems, contribute to anxiety behavior. To investigate whether polymorphisms in the genes regulating these two systems may alter susceptibility to anxiety disorders in humans, we genotyped 71 single nucleotide polymorphisms (SNPs) in CRH, CRHR1, CRHR2, AVP, AVPR1A, AVPR1B in a German sample from Munich with patients suffering from panic disorder and matched healthy controls (n = 186/n = 299). Significant associations were then replicated in a second German sample with 173 patients with panic disorder and 495 controls. In both samples separately and the combined sample, SNPs within CHRH1 and AVPR1B were nominally associated with panic disorder. We then tested two locus multiplicative and interaction effects of polymorphisms of these two genes on panic disorder. Fifteen SNP pairs showed significant multiplicative effects in both samples. The SNP pair with the most significant association in the combined sample (P = 0.00057), which withstood correction for multiple testing, was rs878886 in CRHR1 and rs28632197 in AVPR1B. Both SNPs are of potential functional relevance as rs878886 is located in the 3' untranslated region of the CRHR1 and rs28632197 leads to an arginine to histidine amino acid exchange at position 364 of AVPR1B which is located in the intracellular C-terminal domain of the receptor. These data suggest that polymorphisms in the AVPR1B and the CRHR1 genes alter the susceptibility to panic disorder.

Mood and anxiety disorders are considered stress-related diseases characterized by an impaired function of mineralocorticoid and glucocorticoid receptors (MR and GR, respectively), the major regulatory elements of the hypothalamus-pituitary-adrenocortical (HPA) axis. A number of so-called chaperone proteins moderate the function of these receptors. Genetic variations in one of these chaperones, FKBP5, were associated with antidepressant treatment response in depression and with a major risk-factor for the development of posttraumatic stress disorder. To further investigate the effect of FKPB5 polymorphisms on corticosteroid receptor-mediated HPA axis regulation we conducted the Trier Social Stress test, a standardized procedure to evaluate psychosocial stress response, in 64 healthy volunteers. We genotyped rs4713916, rs1360780 and rs3800737, the three single nucleotide polymorphisms (SNPs) in the FKBP5 region which had shown the strongest effect in previous studies. In addition, we evaluated the effects of the GR polymorphisms Bcl1 and N363S as well as the MR polymorphism I180V. Subjects homozygous for any of the FKBP5 variants displayed an incomplete normalization of the stress-elicited cortisol secretion. This was also observed following a second test additionally accompanied by an increased self-reported anxiety. Regarding GR and MR, only carriers of the Bcl1 variant displayed an altered cortisol response in the prognosticated direction. While Bcl1 was predominantly associated with anticipatory cortisol, homozygous carriers of the FKBP5 minor allele showed insufficient cortisol recovery and increased self-reported anxiety after psychosocial stress. This reaction pattern suggests that subjects carrying these variants are at risk of displaying chronically elevated cortisol levels after repeated stress constituting a risk factor for stress-related diseases.

Following secretion from the posterior pituitary, the neuropeptide vasopressin (AVP) stimulates the kidney to retain water, and when released centrally it can contribute to anxiety- and depression-like behaviours. We hypothesized that CD1 mice bred for low trait anxiety (LAB) suffer from a deficit in AVP. Both osmotically stimulated peripheral secretion and intra-paraventricular nucleus (PVN) release of AVP were found decreased in LAB animals compared with normal anxiety (NAB) or high anxiety (HAB) controls. Consequently, in addition to their extreme non-anxiety, LAB mice showed signs of central diabetes insipidus (cDI), including increased fluid intake and reduced urine osmolality, as well as a pathological increase in plasma osmolality upon water deprivation. These cDI symptoms were attenuated by administration of a selective AVP V2 receptor agonist. A single nucleotide polymorphism (SNP) in exon 1 (C(+40)T) of the Avp gene of LAB animals causes an amino acid substitution in the signal peptide of the AVP precursor, and is likely to impair processing and trafficking of the precursor, as suggested by reduced axonal transport of AVP from the hypothalamic PVN, finally contributing to cDI symptoms and low trait anxiety. In an F2 panel, this SNP co-segregated with fluid intake and showed a partial contribution to low anxiety-related behaviour, indicated by its co-segregation with time spent on the open arms of the elevated plus-maze in a subset of F2 mice. Thus, the SNP-associated deficit in plasma and central AVP contributes to signs of cDI and, at least partially, to low trait anxiety, both features being typical of LAB animals.

Anxiety disorders and specifically panic disorder (PD) are caused by complex interactions of environmental and genetic factors. The latter comprise many different genes, from which those involved in serotonergic neurotransmission have received particular attention. Here we report the results from an association candidate-gene approach, where we analyzed 15 single nucleotide polymorphisms (SNPs) within the gene coding for the serotonin-receptor 2A (HTR2A) in patients suffering from PD and a control sample. We found that the SNP rs2296972 shows an association between the number of T-alleles and severity of symptoms in PD. By performing tests according to the Fisher product method (FPM), an association between HTR2A and the personality trait reward dependence could be shown. Most pronounced effects were observable for the SNPs rs2770304, rs6313, and rs6311. Furthermore, the polymorphisms rs3742278, rs2296972, and rs2770292 form a haplotype, which may be associated with higher susceptibility for PD. These results further underline a possible important role of genetic variations within the system controlling serotonergic neurotransmission for the development and course of disease in PD., ((c) 2007 Wiley-Liss, Inc.)

High thalamocortical neuronal activity characterizes both, wakefulness and rapid eye movement (REM) sleep, but apparently this network fulfills other roles than processing external information during REM sleep. To investigate thalamic and cortical reactivity during human REM sleep, we used functional magnetic resonance imaging with simultaneous polysomnographic recordings while applying acoustic stimulation. Our observations indicate two distinct functional substates within general REM sleep. Acoustic stimulation elicited a residual activation of the auditory cortex during tonic REM sleep background without rapid eye movements. By contrast, periods containing bursts of phasic activity such as rapid eye movements appear characterized by a lack of reactivity to sensory stimuli. We report a thalamocortical network including limbic and parahippocampal areas specifically active during phasic REM periods. Thus, REM sleep has to be subdivided into tonic REM sleep with residual alertness, and phasic REM sleep with the brain acting as a functionally isolated and closed intrinsic loop.

In the adult, corticotropin-releasing hormone (CRH) is the key mediator for the behavioural and neuroendocrine response to stress. It has also been hypothesized that, during postnatal development of the stress system, CRH controls the activity of the HPA axis and mediates the effects of early disturbances, e.g. 24 h of maternal deprivation. In the current study we investigated the function of specific brain corticotropin-releasing hormone receptor type 1 (CRHR1) subpopulations in the control of the HPA axis during postnatal development under basal conditions as well as after 24 h of maternal deprivation. We used two conditional CRHR1-deficient mouse lines which lack this receptor, either specifically in forebrain and limbic structures (Cam-CRHR1) or in all neurons (Nes-CRHR1). Basal circulating corticosterone was increased in Nes-CRHR1 mice compared to controls. Corticosterone response to maternal deprivation was significantly increased in both CRHR1-deficient lines. In the paraventricular nucleus, Cam-CRHR1 animals displayed enhanced CRH and decreased vasopressin expression levels. In contrast, gene expression in Nes-CRHR1 pups was strikingly similar to that in maternally deprived control pups. Furthermore, maternal deprivation resulted in an enhanced response of Cam-CRHR1 pups in the brain, while expression levels in Nes-CRHR1 mouse pups were mostly unchanged. Our results demonstrate that brainstem and/or hypothalamic CRHR1 contribute to the suppression of basal corticosterone secretion in the neonate, while limbic and/or forebrain CRHR1 dampen the activation of the neonatal HPA axis induced by maternal deprivation.

Previous results from our genetic analyses using pedigrees from a French Canadian population suggested that the interval delimited by markers on chromosome 12, D12S86 and D12S378, was the most probable genomic region to contain a susceptibility gene for affective disorders. Association studies with microsatellite markers using a case/control sample from the same population (n = 427) revealed significant allelic associations between the bipolar phenotype and marker NBG6. Since this marker is located in intron 9 of the P2RX7 gene, we analyzed the surrounding genomic region for the presence of polymorphisms in regulatory, coding and intron/exon junction sequences. Twenty four (24) SNPs were genotyped in a case/control sample and 12 SNPs in all pedigrees used for linkage analysis. Allelic, genotypic or family-based association studies suggest the presence of two susceptibility loci, the P2RX7 and CaMKK2 genes. The strongest association was observed in bipolar families at the non-synonymous SNP P2RX7-E13A (rs2230912, P-value = 0.000708), which results from an over-transmission of the mutant G-allele to affected offspring. This Gln460Arg polymorphism occurs at an amino acid that is conserved between humans and rodents and is located in the C-terminal domain of the P2X7 receptor, known to be essential for normal P2RX7 function.

Prominent local decreases in blood oxygenation level (BOLD) can be observed by functional magnetic resonance imaging (fMRI) upon acoustic stimulation during sleep. The goal of this study was to further characterize this BOLD signal decrease with respect to corresponding neurophysiological phenomena using a simultaneous electroencephalography (EEG)/fMRI approach in sleeping human subjects. Healthy volunteers were subjected to acoustic stimulation during non-rapid eye movement (NREM) sleep. On the basis of statistical parametric maps, the correlations between the fMRI response (both amplitude and extent of the BOLD response) and the concomittant changes in the EEG (delta power and K-complexes) were calculated. Amplitude and extent of the stimulus-induced negative BOLD effect correlated positively with measures of EEG synchronization, namely an increase in the number of K-complexes and EEG delta power. Stimulus-induced BOLD decreases were most prominent during light (stage 2) NREM sleep and disappeared during slow wave sleep, indicating an influence of the baseline degree of hyperpolarization. Our observations provide first evidence that 'negative' BOLD signal changes during human sleep are associated with electrophysiological indicators of altered neuronal activity. Increased number of K-complexes and delta power reflecting hyperpolarization suggests true cortical deactivation upon stimulus presentation. This sleep stage-dependent deactivation might serve to protect the brain from arousing stimuli, particularly during the light phases of sleep shortly after sleep onset.

Objective: We conducted a longitudinal high-risk study to identify psychometric vulnerability markers for affective disorders., Method: We examined 82 healthy subjects [high-risk probands (HRPs)] with at least one first-degree relative suffering from an affective disorder. The premorbid psychometric profile of 20 HRPs who developed a psychiatric disorder during follow-up was compared with the profile of control subjects without personal and family history of psychiatric disorders matched for age and gender., Results: Somatization, complaints (vegetative lability), and perception of strain are increased in HRPs who developed a psychiatric disorder. These alterations were not influenced by the time interval until the onset of the disorder., Conclusion: The premorbid psychometric profile in subjects at high risk for affective disorders is characterized by somatization, complaints, and elevated perception of strain. Together with previous findings our results suggest that these alterations can be regarded as potential vulnerability markers for affective disorders.

Background: The high rate of comorbidity between alcoholism and anxiety disorders suggests some causal link. This study used the startle reflex to investigate whether increased reactivity to stimuli inducing fear or related affective states might be one mechanism by which a family genetic risk promotes the development of alcohol use disorders., Methods: Thirty-one sons of alcoholics (PH+) were recruited from the participants of a longitudinal epidemiologic survey representative of the Munich area population between 18 and 25 years. Thirty male low-risk participants without parental alcoholism (PH-) were matched for age and history of psychiatric disorders. The baseline acoustic startle reflex was elicited before and after subjects drank 0.6 g/kg ethanol or placebo in a randomized, double-blind, placebo-controlled crossover design. Thereafter, the startle response was investigated while the subjects' affective state was manipulated by announcement of aversive electric finger stimuli to induce fear potentiation and by presentation of photographic slides previously rated to be pleasant, unpleasant, or neutral in their emotional valence., Results: Plain startle response was lower in PH+ than PH- participants and was equally dampened by alcohol in PH+ and PH- subjects. Threat of finger shocks increased the startle response to the same extent in both groups. This fear potentiation effect was significantly attenuated by alcohol given on the second experimental day but not if alcohol was administered first and placebo on the second day. Pleasant and unpleasant slides decreased and increased startle response, respectively, and this effect was influenced by neither risk group nor alcohol., Conclusions: The acoustic startle reflex seems to be reduced in sons of alcoholics. The nonsignificant results during startle modification do not support the concept of increased reactivity to anxiety-related environmental stimuli as a mechanism promoting alcohol use disorders in subjects at increased family genetic risk for alcoholism.

Brainstem serotonergic neurotransmission is implicated in sleep regulation. However, the role of serotonin (5-HT) in forebrain regions in sleep-wake mechanisms is still unclear. Here, we have investigated, using a combined in vivo microdialysis/electroencephalogram method, the relationship between hippocampal 5-HT levels and sleep-wake behaviour in the rat. A clear-cut relationship was found between hippocampal 5-HT levels and vigilance state. The highest levels of 5-HT were observed during wakefulness, whereas a progressive decrease of 5-HT going from nonrapid eye movement sleep to rapid eye movement sleep was found. Sleep deprivation (SD) causes a transient enhancement of mood in depressed patients. Given the putative role of 5-HT in the aetiology of depression and the therapeutical efficacy of selective serotonin reuptake inhibitors in this illness, we also studied hippocampal 5-HT during 4 h of SD and during the subsequent recovery period. During the whole SD period, 5-HT levels were elevated substantially when compared to 5-HT levels during basal wakefulness. However, no changes in 5-HT levels and the relationship between hippocampal 5-HT and vigilance state were found during the subsequent recovery period. As SD is a potentially stressful experience and glucocorticoids are involved in the regulation of serotonergic neurotransmission and sleep, we investigated the effects of SD on free corticosterone levels. SD caused a marked rise in free corticosterone levels. However, the effects of SD on 5-HT seem not to be mediated by this hormone, because adrenalectomy did not affect the rise in hippocampal 5-HT during SD. We hypothesize that the elevated hippocampal 5-HT levels during SD may participate in the transient mood enhancing properties of forced wakefulness observed in depressed patients.

We investigated the interaction between behavioural dimensions and cognitive performance in the inbred mouse strains C57BL/6 and DBA/2, which have previously been found to differ in cognitive performance and emotionality. Because it has never been evaluated whether cognitive performance and emotional behaviour are interrelated in these strains, we analysed various behavioural dimensions and cognitive functions in parallel using the modified hole board test. We could show that naive BL6 and DBA mice distinctly differed in terms of anxiety-related behaviour. Principal component analysis on the phenotyping data showed that anxiety-related behaviour was described by identical parameters and was not correlated to locomotion in the two strains. During cognitive testing, DBA mice habituated faster and performed better than BL6 mice. Principal component analysis indicated a close correlation between anxiety-related behaviour and cognitive performance in DBA mice, being associated with a highly successful cognitive performance. In BL6 mice, cognition was correlated to general exploration. This correlation turned out to be less successful in performing the modified hole board test. Our findings support the idea that high anxiety may interact with specific cognitive processing, thus offering a promising animal model for future preclinical research on the interaction of anxiety and cognition.

Serotonin is important for adequate coping with stress. Aberrant serotonin function is implicated in the aetiology of major depression and anxiety disorders. Dysregulation of the hypothalamic-pituitary-adrenocortical axis, involving elevated corticotropin-releasing hormone (CRH) activity, also plays a role in these stress-related illnesses. Here we studied the effects of stress on hippocampal serotonin and the role of the CRH system using in vivo microdialysis. First, rats were subjected to a forced swim stress, resulting in a dramatic increase in hippocampal serotonin (1500% of baseline), which was associated with the occurrence of diving behaviour. The diving-associated increase in serotonin depended on activation of CRH receptors, as it was antagonized by intracerebroventricular pretreatment with D-Phe-CRH12-41. Secondly, the effects of intracerebroventricular administration of CRH and urocortin (0.03-1.0 microg) were studied. Both CRH and urocortin caused a dose-dependent rise in hippocampal serotonin (maximally 350% of baseline) and 5-hydroxyindoleacetic acid levels, suggesting the involvement of CRH receptor type 1. Because the effects of urocortin were prolonged, CRH receptor type 2 could play a role in a later phase of the neurotransmitter response. Experiments using adrenalectomized rats showed that CRH-induced serotonin changes were adrenally independent. These data suggest that the raphe-hippocampal serotonin system is able to mount, CRH receptor-dependent, responses to specific stressful situations that surpass the usually observed maximal increases of about 300% of baseline during stress and enhanced vigilance.

Central administration of corticotropin-releasing hormone increases anxiety-like behaviour and arousal in rodents, and increased anxiety-like behaviour has been shown in mice overproducing corticotropin-releasing hormone on an elevated plus maze and in a dark-light emergence task. However, evidence is accumulating that measures obtained from different anxiety tasks may reflect different aspects of anxiety-like behaviour in animals. We therefore tested mice overproducing corticotropin-releasing hormone in a battery of paradigms, studying spontaneous behaviour after a mild stressor, tasks of innate anxiety-like behaviour (light-dark box), lick suppression (Vogel conflict), conditioned fear, and forced swimming. Exploratory behaviour was studied in a 16-hole board task. Furthermore, pain threshold, water intake, locomotor activity and sensorimotor learning/co-ordination were tested to control for confounding factors. In line with previous findings, increased anxiety-like behaviour of transgenic mice was observed in the light-dark box paradigm. However, no differences were seen in the conflict paradigm. Conditioned fear was decreased 1 h but not 24 h after conditioning in transgenic mice, and immobility was decreased [corrected] in forced swimming in corticotropin-releasing hormone overexpressors. Locomotor activity in a novel open field and on the hole board was reduced in transgenics. Exploratory behaviour (hole pokes) was reduced during initial exploration of an unfamiliar hole board. Moreover, sensorimotor performance on a rotorod was impaired, and water intake was reduced in corticotropin-releasing hormone overproducing mice, while no changes were seen in nociception. No differences in locomotor activity were seen in a second group of mice, tested in a familiar open field. When these animals were challenged with diazepam, transgenic mice were less susceptible to the sedative effects of the drug on locomotor activity. These data suggest that corticotropin-releasing hormone overproduction leads to specific effects in a subset of anxiety paradigms, and that these transgenic mice suffer from a motor deficit in addition to altered anxiety-like behaviour/arousal.

The transcription factor cAMP response element-binding protein (CREB) plays a critical role in plasticity processes underlying learning and memory. We investigated the phosphorylation of CREB in rat brain after forced swimming, a stressor known to impact on higher limbic and neocortical brain areas. As shown by immunohistochemistry, forced swimming increased phosphorylated CREB (P-CREB) levels in the dentate gyrus, all neocortical areas, the medial, lateral and basolateral nuclei of the amygdala, cerebellum but not in the hypothalamic paraventricular nucleus. Distinct differences in the P-CREB pattern were observed in the deeper vs. superficial layers of the neocortex. The response in P-CREB was stressor type-specific because exposure to either ether or a cold environment was ineffective. The forced swimming-induced changes in P-CREB levels showed a biphasic time-course: an early peak detected at 15 min was followed by a marked drop at 60 min; a second rise starting after 1-2 h, reached maximal values between 6 and 8 h, and remained elevated for at least 48 h. Examination of the neuroanatomical induction pattern of the CRE-inducible immediate early gene product c-fos revealed that it was only partly overlapping with that of P-CREB. Western analyses showed that only the 43-kDa CREB protein (an enhancer of CRE-containing promotors) was phosphorylated after forced swimming, while other members of the CREB/ATF family (CREM, ATF-1 and ATF-2) remained unaffected. The NF-kappaB pathway was not activated, indicating that forced swimming does not unspecifically evoke transcription factor activation. Thus, in contrast to physical stressors, such as ether or cold exposure, forced swimming, a stressor with a strong psychological component, elicits the recruitment of the CREB pathway in a widespread manner in the limbic system and neocortex; brain regions known to be implicated in various forms of (stress-related) learning and memory.

In major depression, decreased hippocampal volume has been attributed to hypercortisolemia, a frequent sign of the disorder, because in animals an excess of corticosteroids has led to dendritic atrophy, astrogliosis and loss of neurons in this brain region. The present study is the first to investigate the structural integrity of the human hippocampus in major depression and following glucocorticoid treatment. Post-mortem hippocampal tissue from 15 patients who had had major depression or bipolar affective disorder, 10 patients who had been treated with glucocorticoids and 16 controls was assessed using haematoxylin-eosin, Nissl and Bodian staining. The patterns of reactive astrogliosis (glial fibrillary acidic protein, GFAP), synaptic density (synaptophysin), synaptic reorganization (growth-associated protein B-50) and early signs of Alzheimer's disease (Alz-50) were examined immunocytochemically. Multivariate analysis, with the patients' age, tissue fixation time and postmortem delay as covariates, was performed. There was no evidence of neuronal cell loss or other major morphological alterations in any of the groups, nor was there a significant change in the distribution pattern of synaptophysin or Alz-50. Changes in B-50 and GFAP staining were observed in the steroid-treated and depressed patients in areas CA1 and CA2 only. The human hippocampus in major depression and after glucocorticoid treatment does not reveal any major morphological changes or signs of neuronal cell death, but does show subtle alterations in B-50 and GFAP expression in selected parts of the pyramidal cell layer.

Background: Chronic alcoholism is often accompanied by disturbances of the hypothalamic-pituitary-adrenal (HPA) system. Patients with alcoholism frequently show nonsuppression in the dexamethasone (Dex) suppression test and also a blunted increase of adrenocorticotropin (ACTH) after injection of corticotropin-releasing hormone (hCRH). However, the underlying mechanisms have not been fully elucidated. The combined Dex/CRH test (pretreatment with 1.5 mg dexamethasone at 2300 hr, injection of 100 microg hCRH at 1500 hr the next day) has been established as a more sensitive tool to investigate HPA system regulation in depressed patients., Methods: We studied the effect of the combined Dex/CRH test in 19 alcoholic inpatients (9 male, 10 female) during and after withdrawal along with 19 healthy controls., Results: Compared to normal controls, patients showed a severely dysregulated HPA system during withdrawal, with significantly elevated cortisol and ACTH response to hCRH after pretreatment with dexamethasone. After completed withdrawal, cortisol levels after injection of hCRH were almost normalized while ACTH values were partially lower in patients, compared to controls., Conclusions: We conclude that the HPA system is severely disturbed during alcohol withdrawal, possibly reflecting an exaggerated release of hypothalamic corticotropin and vasopressin.

Hyperactivity of central corticotropin-releasing hormone (CRH) circuits appears to contribute to the symptomatology of affective and anxiety disorders and therefore CRH receptor antagonists have attracted attention as potential therapeutic agents. R121919, a novel high-affinity nonpeptide CRH(1) receptor antagonist, displaced (125)I-oCRH in rat pituitary, cortex and amygdala, but not in choroid plexus or cerebral blood vessels in vitro and in vivo, which is consistent with CRH(1) receptor antagonism. In vivo, R121919 significantly inhibited stress-induced corticotropin release in rats selectively bred for high- and low-anxiety-related behaviour but displayed anxiolytic effects in high-anxiety rats only. These data, corroborated by ex vivo receptor occupancy studies, suggest that this animal model is appropriate for the evaluation of CRH(1) receptor antagonists and that compounds such as R121919 will be beneficial whenever the central stress hormone system is hyperactive.

Tricyclic antidepressants and selective serotonin reuptake inhibitors are here shown to induce cell death in a neural cell line. The exposure to these drugs led to increased generation of reactive oxygen species and a concomitant reduction of intracellular glutathione levels. Furthermore, these antidepressants induced DNA fragmentation and increased the transcriptional and DNA-binding activity of NF-kappaB. In contrast, treatment with type A and B monoamine oxidase inhibitors did not induce changes in NF-kappaB activity and did not exert a detrimental influence on cell viability. These results indicate that some antidepressant drugs may cause both oxidative stress and changes in cellular antioxidative capacity, resulting in altered NF-kappaB activity and, ultimately, cell death.

Schizophrenia is a major psychiatric disease, which affects the centre of the personality, with severe problems of perception, cognition as well as affective and social behaviour. In cerebrospinal fluid of drug-free schizophrenic patients, a significant decrease in the level of total glutathione (GSH) by 27% (P<0.05) was observed as compared to controls, in keeping with the reported reduced level of its metabolite gamma-glutamylglutamine. With a new non-invasive proton magnetic resonance spectroscopy methodology, GSH level in medial prefrontal cortex of schizophrenic patients was found to be 52% (P = 0.0012) lower than in controls. GSH plays a fundamental role in protecting cells from damage by reactive oxygen species generated among others by the metabolism of dopamine. A deficit in GSH would lead to degenerative processes in the surrounding of dopaminergic terminals resulting in loss of connectivity. GSH also potentiates the N-methyl-D-aspartate (NMDA) receptor response to glutamate, an effect presumably reduced by a GSH deficit, leading to a situation similar to the application of phencyclidine (PCP). Thus, a GSH hypothesis might integrate many established biological aspects of schizophrenia.

Using intracerebral microdialysis in urethane-anaesthetized adult male Wistar rats, we monitored the effects of acute repetitive transcranial magnetic stimulation (rTMS; 20 trains of 20 Hz, 2.5 s) on the intrahypothalamic release of arginine vasopressin (AVP) and selected amino acids (glutamate, glutamine, aspartate, serine, arginine, taurine, gamma-aminobutyric acid) and the intrahippocampal release of monoamines (dopamine, noradrenaline, serotonin) and their metabolites (homovanillic acid, 3,4-dihydroxyphenylacetic acid, 5-hydroxyindoleacetic acid). The stimulation parameters were adjusted according to the results of accurate computer reconstructions of the current density distributions induced by rTMS in the rat and human brains, ensuring similar stimulation patterns in both cases. There was a continuous reduction in AVP release of up to 50% within the hypothalamic paraventricular nucleus in response to rTMS. In contrast, the release of taurine, aspartate and serine was selectively stimulated within this nucleus by rTMS. Furthermore, in the dorsal hippocampus the extracellular concentration of dopamine was elevated in response to rTMS. Taken together, these data provide the first in vivo evidence that acute rTMS of frontal brain regions has a differentiated modulatory effect on selected neurotransmitter/neuromodulator systems in distinct brain areas.

Transgenic mice with impaired glucocorticoid receptor (GR) function were tested for their ability to learn and perform a series of simultaneous visual discriminations which allowed a dissociation between accuracy of discrimination from those of motivation and behavioural disinhibition. Animals were first trained on an operant five-choice simultaneous discrimination autoshaping procedure, followed by a continuous reinforcement schedule on that task. Subsequently, the number of choices was limited to two and data were analysed according to the mathematical methods of signal detection theory (SDT). The effects of GR-antisense expression on accuracy when different rates of responding were required were studied under different fixed ratio response requirements (FR1-FR10). Autoshaping was retarded in transgenic animals and accuracy was impaired in both the five-choice and the two-choice discrimination tasks, although transgenic mice showed clear evidence for learning. Under conditions of low response requirements, transgenic mice showed increased response and cognitive biases, but reduced perceptual bias, and a behavioural disinhibition, characterized by a reduction in errors of omission, decreased response latencies and increased number of responses during the inter-trial interval. Increasing the response requirement improved performance in transgenic animals as reflected by enhanced accuracy. Moreover, transgenics were less susceptible to the deleterious effects of higher response requirements, as indicated by relatively unaffected bias measures in this group, while bias increased in controls. These results indicate that altered performance in GR-antisense transgenic animals cannot simply be interpreted as a mnemonic deficit, but that altered motivation and enhanced impulsive responding may account for some of these impairments.

The ageing process has been shown to have a profound impact on the hypothalamo-neurohypophysial system (HNS) and the hypothalamo-pituitary-adrenocortical (HPA) axis in humans as well as in rodents. Therefore, in this study, the intracerebral and peripheral release patterns of both vasopressin and oxytocin have been studied in aged male Wistar rats under basal conditions and in response to ethologically relevant stressors, using intracerebral microdialysis and chronic blood sampling techniques, respectively. Approximately a twofold higher basal release of arginine vasopressin (AVP) within the hypothalamic paraventricular nucleus (PVN), but not within the supraoptic nucleus (SON), was found in aged rats, whereas basal oxytocin (OXT) release did not differ in comparison with young rats. With increasing age the rise in intra-PVN release of both AVP and OXT was blunted in response to forced swimming. In contrast, the intra-SON release of AVP was unrelated to age. Simultaneously recorded basal secretion of both AVP and OXT from the neurohypophysis into blood was increased in aged rats, with a blunted OXT response to swim stress. Opposed to that, plasma AVP levels remained unchanged in both groups. Basal plasma levels of corticotropin (ACTH) and corticosterone were elevated in aged rats, whereas stress-elicited ACTH and corticosterone responses were indistinguishable. These results indicate age-related changes in the HNS and HPA axis with an enhanced basal activity opposed to a blunted response to stressors with increasing age. The increased basal release of AVP within the PVN suggests a role of intracerebral AVP in age-associated alterations of HPA axis regulation.

To study the consequences of impaired functioning of the glucocorticoid receptor (GR) for behavioural, neuroendocrine and neurochemical responses to a psychological stressor, a transgenic mouse expressing antisense RNA against GR was used. Previous studies on these transgenic mice have shown that impairment of GR evolves in disturbed neuroendocrine regulation and certain behavioural responses to stress. Here we investigated putative disturbances on the level of brain neurotransmission in GR-impaired (GR-i) mice using an in vivo microdialysis method. Through a microdialysis probe in the hippocampus, serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA) and free corticosterone [as an index of hypothalamic-pituitary-adrenocortical (HPA) axis activity] were monitored. Moreover, specific behaviours (e.g. grooming, eating/drinking, sniffing, nest building and locomotion) displayed by the mice during collection of the dialysates were scored. Measurement of dialysate concentrations of corticosterone on days 1 and 3 after insertion of the microdialysis probe showed that the free levels of this glucocorticoid were significantly lower in GR-i mice toward the evening. On day 2 after insertion of the microdialysis probe, baseline values of dialysate corticosterone, 5-HT and 5-HIAA were assessed, after which mice were exposed to a rat placed into their home cage. The rat and mouse were separated by a Plexiglas wall. A positive correlation between baseline hippocampal extracellular levels of 5-HT and 5-HIAA and the time spent performing active behaviours was observed in both genotypes. The main active behaviour performed at the baseline was grooming behaviour. During the rat exposure period, control mice remained mostly sitting and/or lying with their eyes fixed on the rat. Moreover, they showed a profound rise in free corticosterone levels. In contrast, GR-i mice displayed significantly more activities along the separation wall and a trend toward more grooming behaviour, but no increase of free corticosterone. In both mouse lines, exposure to a rat increased hippocampal extracellular levels of 5-HT and 5-HIAA. The rise in 5-HT was, however, more pronounced in the GR-i mice. From these data it may be concluded that life-long GR impairment has profound consequences for behavioural and neuroendocrine responses to a psychological stressor. Moreover, long-term impaired functioning of GR evolves in hyper-responsiveness of the raphe-hippocampal serotonergic system.

The aim of the present study was to investigate the physiological significance of the neuropeptide arginine vasopressin (AVP) released within the septum, in the behavioural response of rats to stress. In the first experiment, rats were chronically implanted with a microdialysis probe aimed at the mediolateral or ventral septum to monitor the local release of AVP in response to 10 min of forced swimming in 20 degrees C warm water. Exposure to this stressor caused a significant increase in AVP release in both the mediolateral (174 +/- 21%, P < 0.01) and ventral septum (220 +/- 33%, P < 0.01). In contrast, microdialysates collected outside the mediolateral septum or in the lateral ventricle remained at prestress levels throughout the dialysis period. Furthermore, unstressed control animals failed to show significant alterations in vasopressin release in the mediolateral septum. In a second experiment, the introduction of the V1 receptor antagonist d(CH2)5Tyr(Me)AVP into the mediolateral septum via inverse microdialysis concomitant with stressor exposure caused the rats to spend an increased time floating and a reduced time swimming compared to vehicle-treated rats. This effect was acute and also detected 24 h after antagonist administration. Taken together, these findings demonstrate a significant activation of the septal vasopressinergic system in response to swim stress. Furthermore, our data support the view that AVP released within this brain area is involved in the generation of active behavioural strategies aimed at coping with new and challenging situations.

The consequences of glucocorticoid receptor (GR) dysfunction for neuroimmunoendocrine responses to an inflammatory challenge were studied in transgenic mice expressing antisense RNA directed against the GR [GR-impaired (GR-i) mice]. Mice were implanted intraperitoneally with a biotelemetry transmitter to monitor body temperature and locomotion. GR-i mice showed decreased locomotion and body temperature during the dark phase of the diurnal cycle. Intraperitoneal administration of saline caused a rapid increase in body temperature in control mice, which was terminated within 90 min. In GR-i mice, however, body temperature remained elevated for about 6 h. Intraperitoneal injection of endotoxin (10 micrograms/mouse) produced a biphasic fever in control mice. However, in endotoxin-injected GR-i mice, body temperature was not significantly different from their saline-injected controls during the first 6 h. Body temperature then increased and remained elevated during the night period. Both strains showed hypolocomotion after endotoxin. In a second experiment, mice were injected intraperitoneally with saline or endotoxin and killed after 1, 3, 6 or 24 h. In GR-i mice, endotoxin caused an augmented rise in plasma ACTH, but not in corticosterone levels. The endotoxin-induced increase in serum levels of interleukin-1 beta and interleukin-6 was not different between the strains. However, whereas in control mice tumour necrosis factor-alpha levels were below detection at the time points studied, substantial levels of this cytokine were found in the serum of GR-i mice 1 h after endotoxin administration. It may be concluded that life-long impairment of GR evolves in aberrant physiological and humoral responses to an acute inflammatory challenge. These findings expand our understanding about the neuroendocrine and physiological disturbances associated with stress-related disorders.

Free radicals and oxidative stress-induced neuronal cell death have been implicated in a variety of neurological disorders. Therefore, neuroprotection is of primary interest in basic and preclinical neuroscience. Here it is shown that RU486 (mifepristone), a potent antagonist of progesterone and glucocorticoid receptors, protects rat primary hippocampal neurons, clonal mouse hippocampal cells and organotypic hippocampal slice cultures against oxidative stress-induced neuronal cell death. 10(-5) M RU486 prevents intracellular peroxide accumulation and cell death induced by amyloid beta protein, hydrogen peroxide and glutamate, neurotoxins that have been implicated in certain neurodegenerative disorders, including Alzheimer's disease. RU486 has a significant protective effect that is independent of the presence and activation of glucocorticoid or progesterone receptors. The neuroprotective activity of this well-studied drug may have an impact on therapeutic interventions for neurodegenerative conditions which involve peroxidation processes, such as stroke and Alzheimer's disease.

Modulation of the transcriptional message of tyrosine hydroxylase was investigated in vivo in the rat nigrostriatal dopamine system with unmodified antisense oligodeoxynucleotide, mismatch oligodeoxynucleotide or vehicle controls. Oligodeoxynucleotide was infused (0.5 microgram/0.5 microliter/h) unilaterally into the substantia nigra by an osmotic minipump system over 14 days. The presence of oligodeoxynucleotide in the brain was verified by in situ hybridization and fluorescence labelling. Animals treated with unmodified antisense oligodeoxynucleotide showed ipsilateral turning behaviour when challenged systemically with the indirect dopamine agonist amphetamine, whereas mismatch- and vehicle-infused rats showed no such behavioural asymmetries. In the substantia nigra, antisense treatment had no effects on tyrosine hydroxylase mRNA, but it led to a reduction in tyrosine hydroxylase protein content. Tissue levels of dopamine, measured in postmortem tissue punches of the neostriatum and substantia nigra, were reduced in the oligodeoxynucleotide-treated hemisphere. Furthermore, basal extracellular levels of dopamine, monitored by in vivo microdialysis, were also lower in the neostriatum ipsilateral to antisense infusion and showed a weaker response to an amphetamine challenge when compared with the contralateral side. These effects were not observed after infusion of mismatch oligodeoxynucleotide or vehicle into the substantia nigra. Finally, the GABAergic enzyme glutamate decarboxylase was not affected in the antisense-treated substantia nigra, indicating that non-specific damage in this area was not caused by this treatment. Our results indicate that antisense oligodeoxynucleotide treatment against tyrosine hydroxylase in the substantia nigra has behavioural and neurochemical effects that are comparable with known actions of dopamine neurotoxins, which are conventional pharmacological tools for the depletion of dopamine. Furthermore, our data show the potential of antisense targetting to reveal new relationships between neurotransmitter-related enzymes and behavioural parameters, because the possibility of selectively and discretely manipulating tyrosine hydroxylase function is likely to produce new insights into the physiological and behavioural functions of the dopaminergic nigrostriatal system.

A combined in vivo microdialysis/biotelemetry method in freely moving rats was used to study the effects of an endotoxic challenge on brain neurotransmission, hypothalamic-pituitary-adrenocortical (HPA) axis activity, autonomic functions and behaviour. Rats were equipped with a microdialysis probe in the preoptic area and a transmitter for biotelemetry in the peritoneal cavity. Time-dependent changes in noradrenergic and serotonergic neurotransmission, and HPA axis activity were monitored by measuring noradrenaline, serotonin, their metabolites and free corticosterone concentrations in dialysates. Core body temperature, heart rate and locomotion were measured simultaneously by biotelemetry. In addition, total behavioural activity was scored by measuring the time during which rats were active. Intraperitoneal administration of endotoxin (lipopolysaccharide; 100 micrograms/kg body weight) caused a pronounced increase in preoptic extracellular concentrations of noradrenaline and its metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG; 500 and 400% of baseline respectively). No effect was found on preoptic concentrations of serotonin, although the levels of its metabolite 5-hydroxyindoleacetic acid were slightly elevated (120% of baseline). Intraperitoneal lipopolysaccharide caused a marked increase in corticosterone levels, a decline in behavioural activity, and biphasic rises in body temperature and heart rate. Analysis of the time curves revealed that noradrenaline rose in parallel with the first increase in body temperature and the increase in corticosterone levels. Moreover, maximum noradrenaline levels were reached approximately 60 min earlier than the peak in body temperature and corticosterone concentrations. Intraperitoneal pretreatment with the cyclo-oxygenase inhibitor indomethacin prevented the lipopolysaccharide-induced changes in body temperature, heart rate and behavioural activity, whereas the changes in noradrenaline, MHPG and corticosterone were largely, but not completely, reduced. Taken together, the results show that an endotoxic challenge results in a highly differentiated response in brain neurotransmission. We postulate that the profound increase in preoptic noradrenergic neurotransmission may be related to the lipopolysaccharide-evoked induction of fever and/or activation of the HPA axis.

Simultaneous microdialysis in the brain and blood was used to monitor the release of vasopressin and oxytocin within the hypothalamic supraoptic (SON) and paraventricular (PVN) nuclei and into the systemic circulation of urethane-anaesthetized male rats before and after central administration of interleukin-1 beta (IL-1 beta). Following intracerebroventricular infusion of the cytokine (200 ng/5 microliters), the content of vasopressin (up to 278% compared to vehicle-treated control, P < 0.01 compared to vehicle-treated control and preinfusion baseline) but not oxytocin (up to 148%, not significant) in 30-min blood microdialysates was found to be increased. This peripheral release was accompanied by a transient rise in vasopressin (up to 163%, P < 0.05) and oxytocin (up to 182%, P < 0.05) release within the SON, the peak typically occurring during the first and second 30-min collection intervals after IL-1 beta respectively. In contrast, in the simultaneously microdialysed PVN, both vasopressin and oxytocin failed to respond to intracerebroventricular IL-1 beta. In another series of experiments, IL-1 beta was directly infused (20 ng/0.5 microliters) into either the SON or PVN during microdialysis of the corresponding nucleus. The cytokine caused a significant and immediate rise in intra-SON release of both vasopressin (up to 225%, P < 0.01) and oxytocin (up to 178%, P < 0.05). Again, in the PVN, nonapeptide release, although tending to be stimulated in response to intranuclear IL-1 beta, failed to reach statistical significance. The cytokine-induced central and peripheral release pattern appeared to be independent of the rise in body temperature observed after IL-1 beta administration.(ABSTRACT TRUNCATED AT 250 WORDS)

The distribution of interleukin 6 (IL-6) mRNA and IL-6 receptor (IL-6R) mRNA in the brain of adult male rats was studied at the light microscope level by in situ hybridization histochemistry using 35S-labelled oligonucleotides. The transcripts of both genes were localized in the pyramidal neurons and in the granular neurons of the hippocampus, in neurons of the habenular nucleus as well as in the dorsomedial and ventromedial hypothalamus, in the piriform cortex, in scattered neurons of the cortex and in granular cells of the cerebellum. The medial preoptic nucleus and the anterior tip of the lateral ventricle contained mRNA encoding IL-6 and its receptor. Moreover, white matter areas, such as the internal capsule, which consist of only fibres and glial cells, were found to have autoradiographic signals above background. The mRNAs for IL-6 and IL-6R in hippocampus and cerebellum are not different, as shown by Northern blot analyses of RNA isolated from these tissues. We postulate that the cytokine IL-6 is expressed constitutively in discrete regions of the CNS and that it is involved in the mechanisms coordinating metabolic, behavioural and neuroendocrine changes not only during illness but also under normal physiological conditions. Our results suggest that IL-6 mRNA and IL-6R mRNA are colocalized, thus supporting a role of the cytokine in autocrine and paracrine communication.

Nocturnal penile tumescence (NPT), sleep electroencephalogram and testosterone secretion were investigated in 25 nonmedicated male patients with an acute episode of major depression. Twelve patients were reassessed after a stable remission and withdrawal of antidepressants. Four of the 25 patients had no NPT activity during acute depression, but this was reversed after recovery. The area under the NPT curve increased after remission, whereas all other NPT variables remained unchanged. Nocturnal testosterone secretion was enhanced after recovery, whereas the sleep structure remained unchanged. The NPT findings for the depressed patients did not differ from those for a control group, even though the latter group was younger. Hence, there are no general NPT changes that could be used to separate depressed patients and normal controls. However, a lack of NPT seems to be a possible, reversible symptom of depression in men.

Nocturnal sleep of 14 patients with HIV infection was characterized by longer sleep onset latency, shorter total sleep time, reduced sleep efficiency, more time spent awake and in Stage 1. There was significantly less sleep Stage 2 than in healthy controls. REM latency was slightly reduced and correlated negatively with depressive symptomatology, while percentages of REM and slow wave sleep were normal. Patients without complaints at the time of the investigation exhibited similar sleep abnormalities. The results stress the usefulness of polysomnography as a sensitive methodology for detection and monitoring of CNS affection in HIV positive patients.

The current article suggests that the neuroendocrine system constitutes a bidirectional link between the brain and humoral homeostasis in the periphery. Any change of neuronal activity in the brain--regardless whether induced by external stimuli or endogenous errors of metabolism--may result in altered composition of gene products. Among these are peptides which directly or indirectly alter endocrine activity and may concomitantly induce a variety of behavioral effects. This has been experimentally demonstrated by neuropeptidergic manipulation of sleep-electroencephalographic (EEG) measures and behavioral studies in animals. An integral part of the neuroendocrine communication are effects of peripheral hormones upon brain structures and their interactions with the immune system. Within this framework all hormones of the limbic-hypothalamic- pituitary-adrenocortical (LHPA)-axis play a dominant role, because: (1) corticotropin-releasing hormone (CRH) was shown to integrate centrally behavioral and metabolic responses to stress; and (2) corticosteroids exert a host of neurochemical changes within the CNS which by far exceed their primary endocrine feedback action. As a corollary, hyperexposure to corticosteroids induces widespread changes of neuronal cell biology which are of clinical significance for depression research (e.g. neuronal cell loss in the hippocampus, down-regulation of glucocorticoid receptors within monoaminergic neurons). Clinical neuroendocrine research over the past years focussed upon evaluation of pathophysiology underlying dexamethasone resistant cortisol levels or hypercortisolism linked to depression and utilized advanced methods for multihormonal analysis and newly synthesized neuropeptides (e.g. CRH) for challenge studies in combination with neurophysiological assessments.(ABSTRACT TRUNCATED AT 250 WORDS)

Three-hour cortisol-profiles and cortisol responses to a 1 mg dose of dexamethasone were recorded in 31 depressed patients and nine controls. The data indicate that the likelihood of detecting non-suppressible cortisol concentrations after dexamethasone is significantly increased in depressed patients with a hypersecretion of cortisol. However, a considerable subsample of normosecretors shows abnormal DST results. Conversely, hypersecretion is often associated with dexamethasone suppression. In this study a 1 mg-DST did not reflect the adrenocortical activity with ultimate accuracy. Therefore any attempts which correlate psychopathological or biological data with pituitary-adrenal activity and use a DST-result as measure are criticizable . Data derived from volunteers illustrate that medical factors such as weight-loss, steroid-containing contraceptives and sleep deprivation can make a pituitary-adrenal activity test ambiguous.

A dexamethasone suppression test (DST) was administered to 31 inpatients with a severe acute schizophrenic exacerbation 4 or 5 days following admission and repeated after 4 weeks or prior to discharge. We identified 15 patients (48%) who were nonsuppressors on the DST at the first test. To exclude major confounders of DST results we monitored weight constancy and plasma concentrations of dexamethasone. In a subgroup of patients also plasma caffeine contents were determined. Our results indicate that DST nonsuppression occurs frequently among patients with schizophrenic crisis. Since caffeine plasma levels were indistinguishable between suppressors and nonsuppressors we reject that excessive caffeine intake accounts for DST nonsuppression among individuals with schizophrenia. Nonsuppressors had lower plasma dexamethasone levels than suppressors and reversal of the DST status from nonsuppression to suppression was associated with an increase of plasma concentrations of the test drug.

The dexamethasone suppression test based upon analysis of 11-deoxycorticosterone, corticosterone and cortisol was applied to 20 female depressed patients (10 endogenous, 10 neurotic) and 10 healthy controls. Calculating ratios of corticosterone to its biological precursor 11-deoxycorticosterone allows to assess the activity of adrenal 11 beta-hydroxylase. This enzyme activity depends on the mean secretion rate of ACTH. The preliminary data indicate that the sensitivity of the test may be increased when based on this enzyme activity rather than upon plasma cortisol concentrations. The decrease of 11-deoxycorticosterone, a potent mineralocorticoid in relation to corticosterone may contribute to the reduced urine concentrating capacity in patients with endogenous depression.

Clinical practice and pharmacological data suggest a possible antidepressive action of sulpiride given in low dosages. To further explore the therapeutic efficacy of sulpiride 11 patients with an endogenous type of depression were studied during treatment with an oral daily dose of 150 mg sulpiride. The present data allows the conclusion that (A) low dosed sulpiride seems to act as an antidepressant in severe and milder forms of depression, (B) a clinical progress is seen earlier than is common during treatment with tricyclics and (C) a significant increase of drive is observable. However, sulpiride maintenance therapy did not prevent early relapse into depression. The preliminary nature of these clinical observations does not allow conclusions about the ultimate utility of this drug. Moreover, it remains unclear for which patients sulpiride is appropriate or perhaps superior to conventional treatment modalities of depression.