The genetic basis for most patients with pustular skin disease remains elusive.

BACKGROUND: Rare variants in the genes IL36RN, CARD14 and AP1S3 have been identified to cause or contribute to pustular skin diseases, primarily generalized pustular psoriasis (GPP). OBJECTIVES: To better understand the disease relevance of these genes, we screened our cohorts of patients with pustular skin diseases [primarily GPP and palmoplantar pustular psoriasis (PPP)] for coding changes in these three genes. Carriers of single heterozygous IL36RN mutations were screened for a second mutation in IL36RN. METHODS: Coding exons of IL36RN, CARD14 and AP1S3 were sequenced in 67 patients - 61 with GPP, two with acute generalized exanthematous pustulosis and four with acrodermatitis continua of Hallopeau. We screened IL36RN and AP1S3 for intragenic copy-number variants and 258 patients with PPP for coding changes in AP1S3. Eleven heterozygous IL36RN mutations carriers were analysed for a second noncoding IL36RN mutation. Genotype-phenotype correlations in carriers/noncarriers of IL36RN mutations were assessed within the GPP cohort. RESULTS: The majority of patients (GPP, 64%) did not carry rare variants in any of the three genes. Biallelic and monoallelic IL36RN mutations were identified in 15 and five patients with GPP, respectively. Noncoding rare IL36RN variants were not identified in heterozygous carriers. The only significant genotype-phenotype correlation observed for IL36RN mutation carriers was early age at disease onset. Additional rare CARD14 or AP1S3 variants were identified in 15% of IL36RN mutation carriers. CONCLUSIONS: The identification of IL36RN mutation carriers harbouring additional rare variants in CARD14 or AP1S3 indicates a more complex mode of inheritance of pustular psoriasis. Our results suggest that, in heterozygous IL36RN mutation carriers, there are additional disease-causing genetic factors outside IL36RN.

Candidate genes in panic disorder: meta-analyses of 23 common variants in major anxiogenic pathways.

The utilization of molecular genetics approaches in examination of panic disorder (PD) has implicated several variants as potential susceptibility factors for panicogenesis. However, the identification of robust PD susceptibility genes has been complicated by phenotypic diversity, underpowered association studies and ancestry-specific effects. In the present study, we performed a succinct review of case-control association studies published prior to April 2015. Meta-analyses were performed for candidate gene variants examined in at least three studies using the Cochrane Mantel-Haenszel fixed-effect model. Secondary analyses were also performed to assess the influences of sex, agoraphobia co-morbidity and ancestry-specific effects on panicogenesis. Meta-analyses were performed on 23 variants in 20 PD candidate genes. Significant associations after correction for multiple testing were observed for three variants, TMEM132D rs7370927 (T allele: odds ratio (OR)=1.27, 95% confidence interval (CI): 1.15-1.40, P=2.49 × 10(-6)), rs11060369 (CC genotype: OR=0.65, 95% CI: 0.53-0.79, P=1.81 × 10(-5)) and COMT rs4680 (Val (G) allele: OR=1.27, 95% CI: 1.14-1.42, P=2.49 × 10(-5)) in studies with samples of European ancestry. Nominal associations that did not survive correction for multiple testing were observed for NPSR1 rs324891 (T allele: OR=1.22, 95% CI: 1.07-1.38, P=0.002), TPH1 rs1800532 (AA genotype: OR=1.46, 95% CI: 1.14-1.89, P=0.003) and HTR2A rs6313 (T allele: OR=1.19, 95% CI: 1.07-1.33, P=0.002) in studies with samples of European ancestry and for MAOA-uVNTR in female PD (low-active alleles: OR=1.21, 95% CI: 1.07-1.38, P=0.004). No significant associations were observed in the secondary analyses considering sex, agoraphobia co-morbidity and studies with samples of Asian ancestry. Although these findings highlight a few associations, PD likely involves genetic variation in a multitude of biological pathways that is diverse among populations. Future studies must incorporate larger sample sizes and genome-wide approaches to further quantify the observed genetic variation among populations and subphenotypes of PD.

Interleukin-10 family cytokines pathway: genetic variants and psoriasis.

BACKGROUND: Interleukin (IL)-10 family cytokines IL-10, IL-19, IL-20 and IL-24 have been implicated in autoimmune diseases and we have previously reported that genetic variants in the IL10 gene cluster were associated with psoriasis. OBJECTIVES: To analyse the relationship between genetic polymorphisms in the IL10 gene cluster and psoriasis. This study also explores whether there are gene-gene interactions among these genetic polymorphisms. METHODS: A total of 377 patients with psoriasis and 403 matched healthy controls were enrolled to carry out a case-control study for 48 single-nucleotide polymorphisms (SNPs) of the IL10 gene cluster. Genotyping for the SNPs was conducted on the Applied Biosystems 3730 DNA Analyzer using SNPlex® technology. Generalized multifactor dimensionality reduction (GMDR) analysis was applied to discover a likely gene-gene interaction model among the SNPs. RESULTS: The results showed that the allele distributions of IL10 gene cluster SNPs are significantly different between the case and control groups. Carriers of the IL10 T allele (rs1554286) and the IL20 T allele (rs1400986) conferred protection from psoriasis [odds ratio (OR) = 0·63, corrected P-value (Pc) = 0·007; OR = 0·62, Pc = 0·038, respectively]. GMDR analysis displayed a significant gene-gene interaction between IL10 (rs1554286) and IL20 (rs1518108) variants. The strongest protective effect was found with the block 1 haplotype ACATA in the IL10 gene (Pc = 0·004). CONCLUSIONS: This study presents a novel finding that the combination of the two SNPs, IL10 (rs1554286) and IL20 (rs1518108), is associated with a reduced risk of psoriasis. Our results indicate that genetic variants of the immunomodulatory IL10 and IL20 genes may offer a protective effect in Europeans from Russia. Independent studies are required to verify the results and find a possible functional explanation.

European consensus statement on phenotypes of pustular psoriasis.

Pustular psoriasis (PP) is a group of inflammatory skin conditions characterized by infiltration of neutrophil granulocytes in the epidermis to such an extent that clinically visible sterile pustules develop. Because of clinical co-incidence, PP is currently grouped with psoriasis vulgaris (PV). However, PP and PV are phenotypically different, respond differently to treatments and seem to be distinct on the genetic level. In contrast to PV, the phenotypes of PP are not well defined. Descriptions of each form of PP are discordant among standard dermatology textbooks [Saurat Dermatologie 2016, Rook's Dermatology 2016, Fitzpatrick's 2012 and Braun-Falco 2012], encumbering the collection of phenotypically well-matched groups of patients as well as clinical trials. The European Rare and Severe Psoriasis Expert Network (ERASPEN) was founded to define consensus criteria for diagnosis, deeply phenotype large groups of PP patients, analyse the genetics and pathophysiology and prepare for prospective clinical trials. This work reviews historical aspects of these conditions, new genetic findings and presents our initial considerations on the phenotypes of PP and a consensus classification of clinical phenotypes that will be used as a baseline for further, prospective studies of PP. Generalized pustular psoriasis (GPP) is defined as primary, sterile, macroscopically visible pustules on non-acral skin (excluding cases where pustulation is restricted to psoriatic plaques). GPP can occur with or without systemic inflammation, with or without PV and can either be a relapsing (>1 episode) or persistent (>3 months) condition. Acrodermatitis continua of Hallopeau (ACH) is characterized by primary, persistent (>3 months), sterile, macroscopically visible pustules affecting the nail apparatus. Palmoplantar pustulosis (PPP) has primary, persistent (>3 months), sterile, macroscopically visible pustules on palms and/or soles and can occur with or without PV.

[The Role of Neurotrophins and Neurexins Genes in the Risk of Paranoid Schizophrenia in Russians and Tatars].

Schizophrenia affects about 1% of the population. Its etiology is not fully understood. Environmental conditions certainly contribute to the development of schizophrenia, but the determining factor is genetic predisposition: the coefficient of heritability of schizophrenia is about 80%, which is typical for the most highly heritable multifactorial diseases. Polymorphic loci of genes of enzymes and receptors involved in the processes of neuroprotection and neurotrophia play significant role in the development of this disease. In this paper we investigated 48 polymorphic variants of genes of the neurotrophins and neurexins family (BDNF, NTRK2, NTRK3, NGF, NXPH1, and NRXN1) in Russian and Tatar cases and in a control group living in the Republic of Bashkortostan. The results of this study confirm the important role of neurotrophin and neurexin genes in paranoid schizophrenia development.

[Association of polymorphisms in toll-like receptor genes with atopic dermatitis in the Republic of Bashkortostan].

Atopic dermatitis (AD) is a prevalent chronic inflammatory skin disease developing as a result of the interaction between genetic predisposition and environmental factors. Considerable role in allergic diseases development is played by polymorphisms of genes of pattern-recognition receptors (PRR) which are capable of recognizing conservative standard molecular structures (patterns) unique for large pathogen groups. In this study polymorphic variants of PRR genes--Toll-like receptors (TLR1, TLR2, TLR4, TLR5, TLR6, TLR9, TLR10), NOD-like receptors (NOD1, NOD2), lipopolysaccharide receptor CD14 gene, and C11orf30 and LRRC32 genes, located in 11q13.5 region, have been investigated in AD patients and control subjects from the Republic of Bashkortostan. An association of TLR1 (rs5743571 and rs5743604), TLR6 (rs5743794) and TLR10 (rs11466617) with AD was found. Our results confirm an important role of the innate immune system in the pathogenesis of AD and the significance of polymorphisms within the Toll-like receptor 2 subfamily genes in AD development.

Differences between familial and sporadic cases of vitiligo.

BACKGROUND: Most cases of vitiligo are sporadic, but about 10-36% of the patients have positive family history. OBJECTIVE: The aim of our study was to describe differences between familial and sporadic cases of vitiligo. METHODS: A total of 186 adult vitiligo patients were examined, in 173 of whom the level of thyroid peroxidase antibodies, gastric parietal cell antibodies (PCA), antinuclear antibodies (ANA), anti-adrenal cortex antibodies and rheumatoid factor in blood was measured. All patients were divided in two groups: the cases with positive family history of vitiligo (51) and the sporadic cases (135). RESULTS: The risk of onset of the disease up to 20 years of age was higher in the familial group (P=0.008). Patients in familial group showed more widespread depigmentation compared with sporadic cases [body surface area (BSA) over 10%: P=0.004; BSA over 50%: P=0.001]. In familial group, patients had darker skin phototype (P=0.045) and the disease had started more often as a vulgar vitiligo (P=0.008). In sporadic vitiligo group, female gender was a risk factor for more widespread depigmentation (BSA over 10%, P=0.001). Extensive depigmentation was associated with reported triggering factors and mucosal involvement in both groups and with leukotrichia only in familial group. Widespread depigmentation related to the risk of presence of autoantibodies (P=0.03) in sporadic cases of vitiligo (especially of PCA: P=0.04 and ANA: P=0.0002). CONCLUSIONS: In this study, we demonstrated first time that patients with familial vitiligo have a higher risk for vulgar type at the beginning of the disease and female gender increases the risk for more extensive depigmentation in sporadic cases.

The differential transcriptome and ontology profiles of floating and cumulus granulosa cells in stimulated human antral follicles.

Communication between various ovarian cell types is a prerequisite for folliculogenesis and ovulation. In antral follicles granulosa cells divide into two distinct populations of mural and cumulus granulosa cells (CGC), enveloping the antrum and surrounding the oocyte, respectively. Both cell types, with the mural compartment in excess, contribute to the floating granulosa cell (FGC) population in the follicular fluid. The aim of this study was to compare the transcriptomes of FGC and CGC in stimulated antral follicles obtained from 19 women undergoing IVF-ICSI procedure. FGC were obtained from follicular fluid during the follicle puncture procedure and CGC were acquired after oocyte denudation for micromanipulation. Gene expression analysis was conducted using the genome-wide Affymetrix transcriptome array. The expression profile of the two granulosa cell populations varied significantly. Out of 28 869 analysed transcripts 4480 were differentially expressed (q-value < 10(-4)) and 489 showed > or =2-fold difference in the expression level with 222 genes up-regulated in FGC and 267 in CGC. The transcriptome of FGC showed higher expression of genes involved in immune response, hematological system function and organismal injury, although CGC had genes involved in protein degradation and nervous system function up-regulated. Cell-to-cell signalling and interaction pathways were noted in both cell populations. Furthermore, numerous novel transcripts that have not been previously described in follicular physiology were identified. In conclusion, our results provide a solid basis for future studies in follicular biology that will help to identify molecular markers for oocyte and embryo viability in IVF.

Temperature dependence of the sodium pump is altered in the cerebral cortex of CCK2 receptor-deficient mice.

Previously we have shown that the temperature dependence of the sodium pump (Na(+),K(+)-ATPase) is altered under different neuropathological conditions. In this study we compared temperature dependence of the Na(+),K(+)-ATPase in the fronto-parietal cortex of CCK(2) receptor-deficient (homo- and heterozygous) and normal (wild-type) mice. The Arrhenius plot for Na(+),K(+)-ATPase from wild-type brain is non-linear with a breakpoint at 20.3 +/- 0.4 degrees C. In case of the brain cell membrane of CCK(2) receptor-deficient mice (homo- and heterozygous) the breakpoint on Arrhenius plot was detected at 26.0 +/- 1.1 degrees C and 25.4 +/- 0.4 degrees C, respectively. The shift of the breakpoint on the Arrhenius plot established in CCK(2) receptor-deficiency as well as in case of some other pathological conditions confirms that such kind of alteration in the Na(+),K(+)-ATPase temperature dependence is likely related to the homeostatic adjustment of altered function of the sodium pump.

Wfs1 gene deletion causes growth retardation in mice and interferes with the growth hormone pathway.

The aim of present study was to describe changes in gene expression in the temporal lobe of mice induced by deletion of the Wfs1 gene. Temporal lobes samples were analyzed using Affymetrix Mouse Genome 420 2 GeneChips and expression profiles were functionally annotated with GSEA and Ingenuity Pathway Analysis. We found that Wfs1 mutant mice are significantly smaller (20.9 +/- 1.6 g) than their wild-type counterparts (31.0 +/- 0.6 g, P < 0.0001). This difference existed in 129S6 and C57B6 backgrounds. Interestingly, microarray analysis identified upregulation of growth hormone (GH) transcripts and functional analysis revealed activation of GH pathways. In line with microarray data, the level of IGF-1 in the plasma of Wfs1 mutant mice was significantly increased (P < 0.05). Thus, Wfs1 deletion induces growth retardation, whereas the GH pathway is activated. To test the interaction between the Wfs1 deletion and genomic background, mutant mice were backcrossed to two different genetic backgrounds. In line with previous studies, an interaction between a gene knockout and genetic background was found in gene expression profiles in the congenic region. However, genetic background did not alter the effect of the Wfs1 mutation on either body weight or GH pathway activation. Further studies are needed to describe biochemical and molecular changes of the growth hormone axis as well as in other hormones to clarify their role in growth retardation in the Wfs1 mutant mice.

Association analysis of IL20RA and IL20RB genes in psoriasis.

The interleukin-20-receptor I complex (IL-20-RI) is composed of two chains, IL20RA and IL20RB. Its ligands are the three members of the IL19 subfamily of cytokines, IL-19, IL-20 and IL-24. These cytokines are important in the manifestation of psoriatic lesions and, recently, an association of polymorphisms of IL20 with psoriasis has been described. In the present study we tested the hypotheses that genetic variations of the IL-20-RI influence susceptibility to psoriasis and investigated single nucleotide polymorphisms (SNPs) in the IL20RA and IL20RB genes in psoriasis patients (n=254) and healthy controls (n=224). We found no association of any of the investigated SNPs with the disease. Analysis of pairwise linkage disequilibrium (LD) across studied markers revealed a strong level of LD between SNPs within the IL20RA gene and SNPs within the IL20RB gene, and, for both genes six common haplotypes were identified with an estimated frequency >or=1%. Haplotype analyses suggested that the IL20RA haplotype CCG (rs1184860, rs1167846, rs1167849) is significantly associated with psoriasis (OR 3.14, 95% CI 1.61-6.14), whereas the TTG haplotype had a protective effect (OR 0.20, 95% CI 0.07-0.55). The risk haplotype defining SNPs 1167846 and 1184860 were found to modify paired box 5 and homeobox A9 sites, respectively, two transcription factors related to the differentiation of immune cells. Further studies are needed to confirm the genetic association and to investigate the functional relevance of IL20RA haplotypes in psoriasis.

Gene expression study of IL10 family genes in vitiligo skin biopsies, peripheral blood mononuclear cells and sera.

BACKGROUND: Vitiligo is a pigmentation disorder, the cause of which is complex and not yet fully understood. There is a significant change of epidermal cytokines in involved skin of patients with vitiligo compared with uninvolved skin and skin of healthy controls, thus suggesting a possible involvement of cytokines in the pathogenesis of vitiligo. OBJECTIVES: To evaluate potential roles of IL10 family cytokines (IL10, IL19, IL20, IL22 and IL24) in vitiligo. Along with the selected cytokines, we investigated subunits of the receptors (IL10RA, IL10RB, IL20RA and IL22RA1) which are involved in the signalling pathway of the cytokines. METHODS: Quantitative real-time polymerase chain reaction was used to detect mRNA expression levels in samples extracted from skin biopsies and peripheral blood mononuclear cells and an enzyme-linked immunosorbent assay was used to measure protein concentrations in serum from patients with vitiligo and healthy controls. RESULTS: IL22 is significantly associated with vitiligo, especially with the active stage of vitiligo, as shown by results of mRNA expression and supported by results of protein level in sera. IL22 may provoke inflammation which leads to destruction of melanocytes. CONCLUSIONS: The actual role of IL22 during pathogenesis of vitiligo remains to be better characterized. Signal transductions of other investigated cytokines seem to be regulated on the expression level of their receptor complex subunits.

Interpretation of knockout experiments: the congenic footprint.

In gene targeting experiments, the importance of genetic background is now widely appreciated, and knockout alleles are routinely backcrossed onto a standard inbred background. This produces a congenic strain with a substantial segment of embryonic stem (ES)-cell-derived chromosome still flanking the knockout allele, a phenomenon often neglected in knockout studies. In cholecystokynin 2 (Cckbr) knockout mice backcrossed with C57BL/6, we have found a clear 'congenic footprint' of expression differences in at least 10 genes across 40 Mb sequence flanking the Cckbr locus, each of which is potentially responsible for aspects of the 'knockout' phenotype. The expression differences are overwhelmingly in the knockout-low direction, which may point to a general phenomenon of background dependence. This finding emphasizes the need for caution in using gene knockouts to attribute phenotypic effects to genes. This is especially the case when the gene is of unknown function or the phenotype is unexpected, and is a particular concern for large-scale knockout and phenotypic screening programmes. However, the impact of genetic background should not be simply viewed as a potential confound, but as a unique opportunity to study the broader responses of a system to a specific (genetic) perturbation.

Exposure to sixty minutes of hyperoxia upregulates myocardial humanins in patients with coronary artery disease - a pilot study.

In experimental setting the concept of myocardial preconditioning by hyperoxia has been introduced and different intracellular protective mechanisms and their effects have been described. To study whether similar protective phenotype can be induced by hyperoxia also in humans, gene expression profile after hyperoxic exposure was analyzed. Adult patients were randomized to be ventilated with either FiO2 0.4 (n = 14) or 1.0 (n = 10) for 60 minutes before coronary artery bypass grafting. A tissue sample from the right atrial appendage was taken for gene analysis and expression profile analysis on genome wide level by RNA-seq analysis was applied. Exposure to > 96% oxygen for 60 minutes significantly changed the expression of 20 different genes, including upregulation of two different humanins - MTRNR2L2 and MTRNR2L8, and activated a "cell survival" network as detected by Ingenuity Pathway Analyses. We concluded that administration of > 96% oxygen for 1 hour changes gene expression in the myocardium of the patients with coronary artery disease and may enhance cell survival capability.

A screen for genes induced in the amygdaloid area during cat odor exposure.

The aim of a present study was to identify the genes activated or inactivated in the amygdaloid area after the exposure to cat odor. Cat odor exposure was used to induce the ethologically relevant anxiety reaction in male rats. Differential expression of genes was analyzed using the cDNA Representational Difference Analysis (cDNA RDA). Differentially expressed mRNAs were identified by sequencing combined with database search and subsequently verified by dot blot analysis. Exposure of rats to cat odor induced avoidance of odor stimulus and suppressed the exploratory activity of animals. We found that during the cat odor exposure several genes with various functions were activated in the amygdaloid area of rat. Moreover, reverse subtraction resulted in a different set of genes that are inactivated during anxiety response. These genes can be classified according to their function as the neurotransmission related, enzymes, cell cycle regulating proteins and transcription factors. We found that during anxiety response the genes participating directly or indirectly in the synthesis of neurotransmitters (carboxypeptidase E, tyrosine 3-monooxygenase/tryptophan 5-mono-oxygenase activation protein, wolframin) were up regulated. Moreover, a number of genes involved in the signal transduction (Rho GTPase, neurochondrin, Ca/calmodulin-dependent protein kinase) were also activated. Additionally, reverse subtraction in control animals identified several up regulated genes having the antagonistic action to these genes (nischarin, Rab geranylgeranyl transferase). In conclusion, we were able to define the possible pathways linked to the regulation of anxiety response.

7-Nitroindazole, a nitric oxide synthase inhibitor, has anxiolytic-like properties in exploratory models of anxiety.

The action of the novel nitric oxide synthase (NOS) inhibitor 7-nitroindazole (7-NI) was studied in different exploratory models of anxiety. In the rat plus-maze test, 7-NI potently increased time spent on open arms and percentage of open arm visits in a dose dependent manner with the minimal effective dose of 40 mg/kg. 7-NI caused an anxiolytic-like effect in the rat social interaction test. The minimal dose increasing social interaction time was 20 mg/kg. However, the drug also produced a clear sedative effect occurring even at smaller doses (10 mg/kg) in the open field test. 7-NI also showed an anxiolytic-like profile in the mouse light-dark compartment test and in the elevated plus-maze test, but the doses required were higher (80-120 mg/kg) than in rat models. Also, the sedative effect occurred at these doses in open field. We failed to demonstrate any effect of L-arginine either in the rat elevated plus-maze test or in the open field test at doses up to 600 mg/kg IP. These results indicate that there are no major interspecies differences between rats and mice in respect of action of 7-NI. The clear anxiolytic-like action of the nitric oxide synthase inhibitor in four different models shows that nitric oxide is involved in the process of anxiety and that NOS could be a new target in developing anxiolytic drugs.

8-OH-DPAT, but not deramciclane, antagonizes the anxiogenic-like action of paroxetine in an elevated plus-maze.

OBJECTIVE: To investigate whether a 5-hydroxytryptamine (5-HT) reuptake inhibitor (paroxetine) has an anxiogenic-like effect and what possible pharmacological mechanism underlies that action. METHODS: We used the rat elevated plus-maze paradigm followed by measurement of locomotor activity. Some of the rats were subjected to handling and adaptation to the experimental situation, while the rest were naive to the test situation. Paroxetine was administered as a single treatment and in combination with the 5-HT1A receptor agonist (8-OH-DPAT) or 5-HT2A/2C receptor antagonist (deramciclane). RESULTS: The administration of paroxetine induced an anxiogenic-like action in rats adapted to handling, but not in handling naive animals. Treatment with paroxetine (0.1-2 mg/kg) reduced the number of open arm visits and time spent in open arms, and the ratio between open and total arm entries in the elevated plus-maze. Paroxetine also decreased the number of line crossings and head-dips. Paroxetine caused the strongest anti-exploratory action at a dose of 0.5 mg/kg. Paroxetine did not suppress the locomotor activity of rats, showing that the described anti-exploratory effect was behaviourally specific to the plus-maze. Pretreatment with 8-OH-DPAT (0.05 mg/kg) completely reversed the anxiogenic-like action of paroxetine, whereas treatment with deramciclane (2 mg/kg) affected only the number of closed arm visits. Deramciclane (0.5-2 mg/kg) and 8-OH-DPAT (0.01-0.1 mg/kg) changed neither exploratory behaviour nor locomotor activity if given as single treatments to the habituated rats. CONCLUSION: The 5-HT reuptake inhibitor, paroxetine, at a low dose (0.5 mg/kg) induces an anxiogenic-like action in handling adapted rats. The effectiveness of 8-OH-DPAT against paroxetine probably supports a role of both pre- and postsynaptic 5HT-ergic mechanisms in the anxiogenic-like action of paroxetine.

Cholecystokinin2 receptor-deficient mice display altered function of brain dopaminergic system.

RATIONALE: Cholecystokinin (CCK) has been shown to coexist and interact with dopamine in the regulation of behaviour. Two different CCK receptors (CCK1 and CCK2) have an opposite influence on the activity of dopamine neurons. Stimulation of CCK2 receptors decreases the release of dopamine and that receptor could mediate the neuroleptic-like effect of CCK. OBJECTIVE: To investigate the activity of the dopaminergic system in pharmacological experiments on CCK2 receptor (CCK2R)-deficient mice. METHODS: We used age- and sex-matched littermates in all our experiments. To evaluate the behavioural differences, we performed the rotarod test and measured the locomotor activity of animals using computer-connected photoelectric motility boxes. Amphetamine and apomorphine, two dopaminergic drugs with different pharmacodynamic properties, were used to influence the activity of the dopaminergic system in the brain. Neurochemical differences related to the different genotype were analysed by means of high-performance liquid chromatography and radioligand binding studies. RESULTS: Motor co-ordination was significantly impaired in the rotarod test of CCK2R receptor-deficient mice. Moreover, the locomotor activity of heterozygous (+/-) and homozygous (-/-) CCK2R receptor-deficient mice was somewhat reduced. A low dose of apomorphine (0.1 mg/kg), an unselective agonist of dopamine receptors, suppressed locomotor activity significantly more in homozygous (-/-) and heterozygous (+/-) mutant mice than in their wild-type (+/+) littermates. Amphetamine (3-6 mg/kg), increasing release of dopamine from the presynaptic terminals, caused a dose-dependent motor stimulation in wild-type (+/+) mice. In heterozygous (+/-) and homozygous (-/-) mice, a lower dose of amphetamine (3 mg/kg) did not alter the locomotor activity, whereas the higher dose of (6 mg/kg) induced a significantly stronger increase in locomotor activity in homozygous (-/-) mice than in their heterozygous (+/-) and wild-type (+/+) littermates. Despite the changes in the action of apomorphine and amphetamine in homozygous (-/-) mice, we did not find any significant differences in the concentration of dopamine and their metabolites in the striatum or cortex. However, the density of dopamine D2 receptors was significantly increased in the striatum of homozygous (-/-) animals compared with wild-type (+/+) mice. CONCLUSIONS: The targeted mutation of the CCK2 receptor gene induced gene dose-dependent changes in the activity of the dopaminergic system. The sensitivity of presynaptic dopamine receptors was increased in heterozygous (+/-) and homozygous (-/-) animals, whereas the increase in sensitivity of postsynaptic dopamine receptors was apparent only in homozygous (-/-) mice.

Inhibition of nitric oxide synthase causes anxiolytic-like behaviour in an elevated plus-maze.

The action of inhibition of nitric oxide (NO) synthase by NG-nitro-L-arginine methyl ester (L-NAME) (1-20 mg kg-1) on the exploratory behaviour of rats in the elevated plus-maze was studied. L-NAME induced an anxiolytic-like effect in the plus-maze test, showing a reverse U-shape action behaviour, with a maximal effect at 10 mg kg-1. This effect was not related to a non-specific increase in motor activity, since in the open field test L-NAME did not affect locomotor activity of rats. Pretreatment of rats with L-NAME (1-10 mg kg-1) also tended to attenuate the anti-exploratory action of CCK agonist caerulein (5 micrograms kg-1), but this action was not significant. In conclusion, it appears that NO may be involved in the process that can lead to anxiety in the rat.