An association study between two missense variations of the benzodiazepine receptor (peripheral) gene and schizophrenia in a Japanese sample

Translocator Protein Ligand Protects against Neurodegeneration in the MPTP Mouse Model of Parkinsonism

Parkinson's disease is the second most common neurodegenerative disease, after Alzheimer's disease. Parkinson's disease is a movement disorder with characteristic motor features that arise due to the loss of dopaminergic neurons from the substantia nigra. Although symptomatic treatment by the dopamine precursor levodopa and dopamine agonists can improve motor symptoms, no disease-modifying therapy exists yet. Here, we show that Emapunil (AC-5216, XBD-173), a synthetic ligand of the translocator protein 18, ameliorates degeneration of dopaminergic neurons, preserves striatal dopamine metabolism, and prevents motor dysfunction in female mice treated with the MPTP, as a model of parkinsonism. We found that Emapunil modulates the inositol requiring kinase 1α (IRE α)/X-box binding protein 1 (XBP1) unfolded protein response pathway and induces a shift from pro-inflammatory toward anti-inflammatory microglia activation. Previously, Emapunil was shown to cross the blood-brain barrier and to be safe and well tolerated in a Phase II clinical trial. Therefore, our data suggest that Emapunil may be a promising approach in the treatment of Parkinson's disease.SIGNIFICANCE STATEMENT Our study reveals a beneficial effect of Emapunil on dopaminergic neuron survival, dopamine metabolism, and motor phenotype in the MPTP mouse model of parkinsonism. In addition, our work uncovers molecular networks which mediate neuroprotective effects of Emapunil, including microglial activation state and unfolded protein response pathways. These findings not only contribute to our understanding of biological mechanisms of translocator protein 18 (TSPO) function but also indicate that translocator protein 18 may be a promising therapeutic target. We thus propose to further validate Emapunil in other Parkinson's disease mouse models and subsequently in clinical trials to treat Parkinson's disease.

Investigation of TSPO variants in schizophrenia and antipsychotic treatment outcomes

Aim: TSPO is a neuroinflammatory biomarker and emerging therapeutic target in psychiatric disorders. We evaluated whether TSPO polymorphisms contribute to interindividual variability in schizophrenia, antipsychotic efficacy and antipsychotic-induced weight gain. Patients & methods: We analyzed TSPO polymorphisms in 670 schizophrenia cases and 775 healthy controls. Gene–gene interactions between TSPO and other mitochondrial membrane protein-encoding genes (VDAC1 and ANT1) were explored. Positive findings were evaluated in two independent samples (Munich, n = 300; RUPP, n = 119). Results: TSPO rs6971 was independently associated with antipsychotic-induced weight gain in the discovery (puncor = 0.04) and RUPP samples (p = 3.00 × 10-3), and interacted with ANT1 rs10024068 in the discovery (p = 1.15 × 10-3) and RUPP samples (p = 2.76 × 10-4). Conclusion: Our findings highlight TSPO as a candidate for future investigations of antipsychotic-induced weight gain, and support the involvement of mitochondrial membrane components in this serious treatment side effect.

Original submitted 20 August 2014; Revision submitted 3 November 2014

Inflammatory cytokines and neurological and neurocognitive alterations in the course of schizophrenia

A growing body of evidence suggests that immune alterations, especially those related to inflammation, are associated with increased risk of schizophrenia and schizophrenia-related brain alterations. Much of this work has focused on the prenatal period, because infections during pregnancy have been repeatedly (albeit inconsistently) linked to risk of schizophrenia. Given that most infections do not cross the placenta, cytokines associated with inflammation (proinflammatory cytokines) have been targeted as potential mediators of the damaging effects of infection on the fetal brain in prenatal studies. Moreover, additional evidence from both human and animal studies suggests links between increased levels of proinflammatory cytokines, immune-related genes, and schizophrenia as well as brain alterations associated with the disorder. Additional support for the role of altered immune factors in the etiology of schizophrenia comes from neuroimaging studies, which have linked proinflammatory cytokine gene polymorphisms with some of the structural and functional abnormalities repeatedly found in schizophrenia. These findings are reviewed and discussed with a life course perspective, examining the contribution of inflammation from the fetal period to disorder presentation. Unexplored areas and future directions, such as the interplay between inflammation, genes, and individual-level environmental factors (e.g., stress, sleep, and nutrition), are also discussed.

Stratified medicine in psychiatry: a worrying example or new opportunity in the treatment of anxiety?

Stratified medicine is a new term that figures highly in current MRC and NHS strategy. It has developed from the earlier terms individualised or personalised medicine and refers to the use of genetic and/or endophenotypic measures to allow better targeting of treatments. The best exemplar is HER2 positivity in breast cancer to determine the efficacy of Herceptin. Clinical trials of this anti-cancer drug were initially unpromising, but once the HER2 positive subgroup was identified it was found, in this subgroup only, to be highly effective. It is presumed that similar subgroups will be found for many common disorders not just cancers, and that these will lead to much better targeted treatments. Such an advance may be necessary to develop new treatments in certain fields where the development of broad-spectrum/blockbuster treatments appears to have reached the end of the road; a particular example of this is in psychiatry. In this paper we discuss this issue in relation to psychiatry using a new and interesting example of how genotyping might help rescue an apparently failed novel treatment in anxiety disorders.

Effects and Mechanisms of 3α,5α,-THP on Emotion, Motivation, and Reward Functions Involving Pregnane Xenobiotic Receptor

Progestogens [progesterone (P(4)) and its products] play fundamental roles in the development and/or function of the central nervous system during pregnancy. We, and others, have investigated the role of pregnane neurosteroids for a plethora of functional effects beyond their pro-gestational processes. Emerging findings regarding the effects, mechanisms, and sources of neurosteroids have challenged traditional dogma about steroid action. How the P(4) metabolite and neurosteroid, 3α-hydroxy-5α-pregnan-20-one (3α,5α-THP), influences cellular functions and behavioral processes involved in emotion/affect, motivation, and reward, is the focus of the present review. To further understand these processes, we have utilized an animal model assessing the effects, mechanisms, and sources of 3α,5α-THP. In the ventral tegmental area (VTA), 3α,5α-THP has actions to facilitate affective, and motivated, social behaviors through non-traditional targets, such as GABA, glutamate, and dopamine receptors. 3α,5α-THP levels in the midbrain VTA both facilitate, and/or are enhanced by, affective and social behavior. The pregnane xenobiotic receptor (PXR) mediates the production of, and/or metabolism to, various neurobiological factors. PXR is localized to the midbrain VTA of rats. The role of PXR to influence 3α,5α-THP production from central biosynthesis, and/or metabolism of peripheral P(4), in the VTA, as well as its role to facilitate, or be increased by, affective/social behaviors is under investigation. Investigating novel behavioral functions of 3α,5α-THP extends our knowledge of the neurobiology of progestogens, relevant for affective/social behaviors, and their connections to systems that regulate affect and motivated processes, such as those important for stress regulation and neuropsychiatric disorders (anxiety, depression, schizophrenia, drug dependence). Thus, further understanding of 3α,5α-THP's role and mechanisms to enhance affective and motivated processes is essential.

Progesterone turnover to its 5α-reduced metabolites in the ventral tegmental area of the midbrain is essential for initiating social and affective behavior and progesterone metabolism in female rats

BACKGROUND

Among women and female rodents, progesterone (P) influences social affiliation and affect. These effects may be partly due to formation of its 5α-reduced, 3α- hydroxylated metabolite, 5α-pregnan-3α-ol-20-one (3α,5α- THP).

AIM

To elucidate whether actions of 3α,5α-THP in the midbrain ventral tegmental area (VTA) are both necessary and sufficient to enhance non-sexual and sexual social behaviors, affect, and central 3α,5α-THP metabolism.

MATERIALS AND METHODS

P and 3α,5α-THP formation were unperturbed or blocked in VTA via infusions of vehicle, PK11195 (400 ng), and/or indomethacin (10 μg). Rats then received subsequent infusions of vehicle or 3α,5α-THP (100 ng) and were assessed in a battery of tasks that included open field (exploration), elevated plus maze (anxiety behavior), social interaction (social affiliation), and paced mating (sexual behavior) or were not tested. Metabolic turnover of P to its 5α-reduced metabolites was assessed in plasma, midbrain, hippocampus, frontal cortex, diencephalon, and remaining subcortical tissues (control interbrain).

RESULTS

Infusions of any combination of inhibitors significantly reduced social and affective behavior in all tasks compared to vehicle, concomitant with reduced turnover of P to its 5α-reduced metabolites, in midbrain only. Subsequent infusions of 3α,5α-THP significantly reinstated/enhanced anti- anxiety behavior, lordosis, and P turnover to its 5α-reduced metabolites in midbrain, as well as hippocampus, cortex, and diencephalon (but not plasma or interbrain).

CONCLUSIONS

These data are the first to provide direct evidence that actions of 3α,5α-THP in the VTA are both necessary and sufficient for social and affective behavior, as well as initiation of central 5α-reduction.

Two binding sites for [3H]PBR28 in human brain: implications for TSPO PET imaging of neuroinflammation

[(11)C]PBR28, a radioligand targeting the translocator protein (TSPO), does not produce a specific binding signal in approximately 14% of healthy volunteers. This phenomenon has not been reported for [(11)C]PK11195, another TSPO radioligand. We measured the specific binding signals with [(3)H]PK11195 and [(3)H]PBR28 in brain tissue from 22 donors. Overall, 23% of the samples did not generate a visually detectable specific autoradiographic signal with [(3)H]PBR28, although all samples showed [(3)H]PK11195 binding. There was a marked reduction in the affinity of [(3)H]PBR28 for TSPO in samples with no visible [(3)H]PBR28 autoradiographic signal (K(i)=188+/-15.6 nmol/L), relative to those showing normal signal (K(i)=3.4+/-0.5 nmol/L, P<0.001). Of this latter group, [(3)H]PBR28 bound with a two-site fit in 40% of cases, with affinities (K(i)) of 4.0+/-2.4 nmol/L (high-affinity site) and 313+/-77 nmol/L (low-affinity site). There was no difference in K(d) or B(max) for [(3)H]PK11195 in samples showing no [(3)H]PBR28 autoradiographic signal relative to those showing normal [(3)H]PBR28 autoradiographic signal. [(3)H]PK11195 bound with a single site for all samples. The existence of three different binding patterns with PBR28 (high-affinity binding (46%), low-affinity binding (23%), and two-site binding (31%)) suggests that a reduction in [(11)C]PBR28 binding may not be interpreted simply as a reduction in TSPO density. The functional significance of differences in binding characteristics warrants further investigation.

The spontaneous Ala147Thr amino acid substitution within the translocator protein influences pregnenolone production in lymphomonocytes of healthy individuals

The de novo production of steroids and neurosteroids begins in mitochondria by the conversion of cholesterol to pregnenolone through cytochrome P450 side-chain cleavage (CYP11A1) enzymatic activity. The C-terminal amino acid domain of the translocator protein (TSPO) has been demonstrated to bind cholesterol, thereby determining its mitochondrial translocation. The goal of the present study was to investigate the effect of the Ala147Thr single-nucleotide polymorphism localized in this TSPO region on pregnenolone production in healthy volunteers. Pregnenolone production was evaluated in a peripheral cell model, represented by circulating lymphomonocytes. First, CYP11A1 expression, both at mRNA and protein level, was demonstrated. Pregnenolone production varied among genotype groups. Comparison of pregnenolone mean values revealed that Thr147 homozygous or heterozygous individuals had significantly lower pregnenolone levels compared with Ala147 homozygous individuals. These findings suggested a dominant effect of the minor allelic variant Thr147 to produce this first metabolite of the steroidogenesis pathway. Interestingly, Ala147 homozygous individuals exhibited significant higher levels of circulating cholesterol-rich low-density lipoproteins with respect to heterozygous individuals. In conclusion, our results demonstrate that the Ala147Thr spontaneous amino acid substitution within TSPO is able to affect pregnenolone production; this should encourage further studies to investigate its potential role in polygenic dyslipidemias.

An association analysis of synapse-associated protein 97 (SAP97) gene in schizophrenia

SAP97 gene encodes the synaptic scaffolding PDZ proteins that interact with the L: -alpha-amino-3-hydroxyl-5-methylisoxazole-4-propionate (AMPA), kainate and N-methyl-D: -aspartate (NMDA) type glutamate receptors. Because the disturbed glutamate neurotransmission has been implicated in the pathophysiology of schizophrenia, we investigated association between the SAP97 gene and schizophrenia. We genotyped 23 SNPs capturing the known common haplotype variations of the gene in a sample comprising 229 schizophrenic patients and 214 matched controls. In a single marker analysis, ten SNPs displayed nominally significant (P < 0.05) association with schizophrenia, although the P values of these SNPs were non-significant after the Bonferroni correction. We also compared haplotype estimates based on case--control genotypes and observed significant association of eight-two- and three- SNP haplotypes with schizophrenia following permutation-based correction. Further examination of the above series of SNPs or haplotypes in each gender revealed significant associations between some of these SNPs or haplotypes and the disorder only in males. The present findings suggest that the SAP97 gene may be a susceptibility factor in male schizophrenics and that the modification of the glutamate receptors-SAP97 signaling pathway could be involved in the disease pathophysiology.

Kinetic analysis in healthy humans of a novel positron emission tomography radioligand to image the peripheral benzodiazepine receptor, a potential biomarker for inflammation

The peripheral benzodiazepine receptor (PBR) is upregulated on activated microglia and macrophages and thereby is a useful biomarker of inflammation. We developed a novel PET radioligand, [(11)C]PBR28, that was able to image and quantify PBRs in healthy monkeys and in a rat model of stroke. The objective of this study was to evaluate the ability of [(11)C]PBR28 to quantify PBRs in brain of healthy human subjects. Twelve subjects had PET scans of 120 to 180 min duration as well as serial sampling of arterial plasma to measure the concentration of unchanged parent radioligand. One- and two-tissue compartmental analyses were performed. To obtain stable estimates of distribution volume, which is a summation of B(max)/K(D) and nondisplaceable activity, 90 min of brain imaging was required. Distribution volumes in human were only approximately 5% of those in monkey. This comparatively low amount of receptor binding required a two-rather than a one-compartment model, suggesting that nonspecific binding was a sizeable percentage compared to specific binding. The time-activity curves in two of the twelve subjects appeared as if they had no PBR binding-i.e., rapid peak of uptake and fast washout from brain. The cause(s) of these unusual findings are unknown, but both subjects were also found to lack binding to PBRs in peripheral organs such as lung and kidney. In conclusion, with the exception of those subjects who appeared to have no PBR binding, [(11)C]PBR28 is a promising ligand to quantify PBRs and localize inflammation associated with increased densities of PBRs.

Transmission disequilibrium test provides evidence of association between promoter polymorphisms in 22q11 gene DGCR14 and schizophrenia

Recent research has suggested that the DiGeorge syndrome critical region gene 14 (DGCR14) exhibits activity differences of more than 1.5 fold between the haplotypes of the variants in the promoter region. DGCR14 is located at 22q11.21, an acknowledged region for susceptibility to schizophrenia. To test the hypothesis that DGCR14 may be involved in the etiology of the disease, we carried out a family-based association study between the reported functional markers and schizophrenia in 235 Chinese Han trios. We found significant evidence of preferential transmission of the promoter variants of DGCR14 across all the trios (Best p-value = 0.00038, Global p-value = 0.0008). The positive results have suggested that DGCR14 is likely to play an important role in the etiology of schizophrenia in the Chinese Han population.

Bipolar I disorder and schizophrenia: a 440-single-nucleotide polymorphism screen of 64 candidate genes among Ashkenazi Jewish case-parent trios

Bipolar, schizophrenia, and schizoaffective disorders are common, highly heritable psychiatric disorders, for which familial coaggregation, as well as epidemiological and genetic evidence, suggests overlapping etiologies. No definitive susceptibility genes have yet been identified for any of these disorders. Genetic heterogeneity, combined with phenotypic imprecision and poor marker coverage, has contributed to the difficulty in defining risk variants. We focused on families of Ashkenazi Jewish descent, to reduce genetic heterogeneity, and, as a precursor to genomewide association studies, we undertook a single-nucleotide polymorphism (SNP) genotyping screen of 64 candidate genes (440 SNPs) chosen on the basis of previous linkage or of association and/or biological relevance. We genotyped an average of 6.9 SNPs per gene, with an average density of 1 SNP per 11.9 kb in 323 bipolar I disorder and 274 schizophrenia or schizoaffective Ashkenazi case-parent trios. Using single-SNP and haplotype-based transmission/disequilibrium tests, we ranked genes on the basis of strength of association (P<.01). Six genes (DAO, GRM3, GRM4, GRIN2B, IL2RB, and TUBA8) met this criterion for bipolar I disorder; only DAO has been previously associated with bipolar disorder. Six genes (RGS4, SCA1, GRM4, DPYSL2, NOS1, and GRID1) met this criterion for schizophrenia or schizoaffective disorder; five replicate previous associations, and one, GRID1, shows a novel association with schizophrenia. In addition, six genes (DPYSL2, DTNBP1, G30/G72, GRID1, GRM4, and NOS1) showed overlapping suggestive evidence of association in both disorders. These results may help to prioritize candidate genes for future study from among the many suspected/proposed for schizophrenia and bipolar disorders. They provide further support for shared genetic susceptibility between these two disorders that involve glutamate-signaling pathways.

3alpha-hydroxy-5alpha-pregnan-20-one in the midbrain ventral tegmental area mediates social, sexual, and affective behaviors

Progestins mediate the onset and duration of lordosis, the mating posture of female rodents, through actions in the hypothalamus and ventral tegmental area. In the hypothalamus, progesterone has traditional, "genomic" actions via intracellular progestin receptors. In the ventral tegmental area, 3alpha-hydroxy-5alpha-pregnan-20-one has "non-genomic" actions independent of progestin receptors to facilitate lordosis that involve GABA(A)/benzodiazepine receptors, NMDA type glutamate receptors, and/or dopamine receptors. 3alpha-Hydroxy-5alpha-pregnan-20-one levels also change with behavioral and/or environmental stimuli and may have a role in other reproductively-relevant behaviors, such as affiliation, exploration, and anxiety (socio-sexual behaviors). Data are reviewed that support the notion that: 1) effects of 3alpha-hydroxy-5alpha-pregnan-20-one in the midbrain ventral tegmental area facilitate lordosis and other reproductively-relevant behaviors. 2) 3alpha-Hydroxy-5alpha-pregnan-20-one, formed in the ventral tegmental area from metabolism of progestins, produced peripherally by endocrine glands, or centrally from biosynthesis in glial cells mediates socio-sexual behaviors. 3) 3alpha-Hydroxy-5alpha-pregnan-20-one's actions at GABA(A)/benzodiazepine receptors, NMDA type glutamate receptors, and dopamine receptors in the ventral tegmental area are important for lordosis; however, effects at these substrates on socio-sexual behaviors have not been elucidated. Given 3alpha-hydroxy-5alpha-pregnan-20-one's involvement in stress responses, its putative role as a homeostatic regulator and in the pathophysiology and treatment of neuropsychiatric disorders is discussed.

Role of neuroactive steroid allopregnanolone in antipsychotic-like action of olanzapine in rodents

Olanzapine increases brain allopregnanolone (ALLO) levels sufficiently to modulate neuronal activity by allosterically regulating GABAA receptors. Recently, we reported the antipsychotic-like profile of ALLO in rodents. The present study examined the hypothesis that olanzapine-induced elevation of endogenous neurosteroid ALLO is vital for its neuroleptic-like action. The conditioned avoidance response (CAR) and apomorphine-induced climbing behavioral paradigms were used in rodents. Administration of ALLO (1 microg, intracerebroventricular (i.c.v.)) or neurosteroidogenic agents such as the mitochondrial diazepam binding inhibitor receptor agonist, FGIN 1-27 (0.5 microg, i.c.v.) or the ALLO precursor, progesterone (10 mg/kg, i.p.) significantly potentiated olanzapine-induced blockade of CAR and apomorphine-induced climbing. In contrast, these agents failed to alter the antipsychotic-like effect of risperidone and haloperidol. On the other hand, inhibition of the endogenous biosynthesis of neurosteroids by the 3beta-hydroxysteroid dehydrogenase inhibitor, trilostane (30 mg/kg, i.p.), the 3alpha-hydroxysteroid oxidoreductase inhibitor, indomethacin (5 mg/kg, i.p.), or the GABAA receptor antagonist bicuculline (1 mg/kg, i.p.) and dehydroepiandrosterone sulfate (DHEAS) (1 mg/kg, i.p.) blocked the effect of olanzapine, but not of risperidone and haloperidol. Socially isolated animals, known to exhibit decreased brain ALLO and GABAA receptor functions, displayed a shortening in the muscimol-induced loss of righting reflex and an increased susceptibility to apomorphine-induced climbing. Administration of olanzapine, but not of haloperidol and risperidone, normalized the duration of muscimol-elicited loss of righting reflex. Although all three antipsychotics proved capable of antagonizing the apomorphine-induced climbing, a dose almost five times higher of olanzapine was required in socially isolated animals. The data obtained suggest that enhancement of the GABAergic tone plays a key role in the antipsychotic-like effect exerted by olanzapine in rodents, likely as a consequence of augmented levels of neuroactive steroids, in particular ALLO, in the brain. The present findings provide the first specific behavioral evidence in support of the hypothesis that neuroactive steroid ALLO- mediated GABAergic modulation is essential for the antipsychotic-like action of olanzapine.

GABA and schizophrenia: a review of basic science and clinical studies

BACKGROUND

A converging body of evidence implicates the gamma-aminobutyric acid (GABA) neurotransmitter system in the pathogenesis of schizophrenia.

METHODS

The authors review neuroscience literature and clinical studies investigating the role of the GABA system in the pathophysiology of schizophrenia. First, a background on the GABA system is provided, including GABA pharmacology and neuroanatomy of GABAergic neurons. Results from basic science schizophrenia animal models and human studies are reviewed. The role of GABA in cognitive dysfunction in schizophrenia is then presented, followed by a discussion of GABAergic compounds used in monotherapy or adjunctively in clinical schizophrenia studies.

RESULTS

In basic studies, reductions in GABAergic neuronal density and abnormalities in receptors and reuptake sites have been identified in several cortical and subcortical GABA systems. A model has been developed suggesting GABA's role (including GABA-dopamine interactions) in schizophrenia. In several clinical studies, the use of adjunctive GABA agonists was associated with greater improvement in core schizophrenia symptoms.

CONCLUSIONS

Alterations in the GABA neurotransmitter system are found in clinical and basic neuroscience schizophrenia studies as well as animal models and may be involved in the pathophysiology of schizophrenia. The interaction of GABA with other well-characterized neurotransmitter abnormalities remains to be understood. Future studies should elucidate the potential therapeutic role for GABA ligands in schizophrenia treatment.

Decreased platelet peripheral-type benzodiazepine receptors in persistently violent schizophrenia patients

Peripheral-type benzodiazepine receptors (PBR) have been shown to be sensitive to stressful conditions. This study aimed to explore a possible association of platelets PBR binding with aggressive behavior and homicidal history in schizophrenia patients. The authors compared [(3)H] PK 11195 binding to platelet membrane among 11 currently aggressive schizophrenia patients, 15 schizophrenia patients with homicidal history, 14 nonaggressive schizophrenia patients, and 15 healthy volunteers. Subjects were assessed for aggressive behavior, psychopathology, anxiety, anger, and emotional distress using standardized instruments. We found that currently aggressive patients had significantly lower (-30%) platelet PBR density (B(max)), and scored significantly higher on hostility, anxiety, state anger, and emotional distress compared to homicidal and nonaggressive schizophrenia patients and healthy controls. Predominance of positive or negative symptoms, homicidal or suicidal attempt history, emotional distress levels, and conventional or atypical antipsychotic therapy is not associated with the expression of platelet PBR binding sites. Significant negative correlations emerged between PBR density and scores for aggressive behavior, hostility and anxiety. Thus, decreased platelet PBR density in aggressive schizophrenia patients is associated with higher scores for overt aggression, hostility and anxiety, but independent of illness subtype, homicidal and suicidal attempt history, distress level and type of antipsychotic treatment.

Effects of olanzapine infusions to the ventral tegmental area on lordosis and midbrain 3alpha,5alpha-THP concentrations in rats

RATIONALE

The progesterone metabolite and neurosteroid 5alpha-pregnane-3alpha-ol-20-one (3alpha,5alpha-THP) facilitates sexual behavior of estradiol-primed rodents through its actions in the ventral tegmental area (VTA). Olanzapine, an atypical antipsychotic, may exert some of its actions by increasing 3alpha,5alpha-THP levels.

OBJECTIVE

If olanzapine has effects by increasing 3alpha,5alpha-THP levels, then olanzapine administration to the VTA should facilitate feminine sexual behavior of estradiol-primed rodents concomitant with increasing midbrain levels of 3alpha,5alpha-THP. METHODS. In experiment 1, ovariectomized rats with bilateral cannulae to the VTA were primed with estradiol at 0 h, infused with olanzapine (10 or 20 microg) or vehicle at 47 h, and tested for sexual behavior at 47.5 h. In experiment 2, estradiol-primed ovariectomized rats were infused with olanzapine (10 microg) or vehicle, tested for sexual behavior, then tissues were collected for measurement of midbrain progesterone and 3alpha,5alpha-THP, and plasma corticosterone, progesterone, and 3alpha,5alpha-THP. In experiment 3, estradiol-primed, ovariectomized rats were administered progesterone (500 microg, SC), tested for sexual behavior, then tissues were collected for midbrain and plasma progesterone and 3alpha,5alpha-THP levels.

RESULTS

Infusions of 10 or 20 microg olanzapine to the VTA significantly increased the incidence and intensity of lordosis, and the occurrence of proceptive and aggressive behaviors. Rats infused with olanzapine to the VTA had significantly greater levels of midbrain 3alpha,5alpha-THP than did vehicle-administered rats. Olanzapine did not increase progesterone or corticosterone levels.

CONCLUSIONS

Olanzapine increases lordosis and midbrain 3alpha,5alpha-THP when infused to the VTA which suggest that olanzapine's behavioral effects may result, in part, through actions of 3alpha,5alpha-THP, independent of progesterone or corticosterone.

No association of two missense variations of the benzodiazepine receptor (peripheral) gene and mood disorders in a Japanese sample

The benzodiazepine receptor (peripheral) (BZRP) plays an important role in the steroid syntheses of the adrenal glands and brain, which is possibly involved in the pathophysiology of mood disorders. We evaluated an association study between two missense variations of the BZRP gene and mood disorders in a Japanese sample. However, no statistically significant associations with either bipolar disorders or depressive disorders were observed in the allele frequencies, genotype counts, or haplotype distributions for the two variations, although the present sample size had a moderate power (0.46-0.86). These results do not suggest that the BZRP gene plays a role in the genetic predisposition of affective disorders.