Environmental stress and its interaction with genetic variation are key contributors in the development of depression and anxiety, yet there is a failure to identify replicable genetic variants and gene-interaction effects in the background of these psychiatric symptoms. Recently it has been reported that 5-HTTLPR and NOSI interact with financial but not other types of recent stressors in the development of depression. In the present study we investigated the interaction of GABRA6 rs3219151 and CNR1 rs7766029 in interaction with different types of recent life events on the presence of depression and anxiety in a large general population sample. 2191 participants completed the List of Threatening Experiences questionnaire which covers four categories of stressful life events (financial problems, illness/personal problems, intimate relationships, and social network) experienced over the previous year and the Brief Symptom Inventory for depression and anxiety symptoms. Participants were genotyped for rs3219151 and rs7766029. Data were analyzed with linear regression models with age and gender as covariates. Results indicated that CNR1 rs7766029 interacted significantly with financial but not other types of life events both in case of depression and anxiety symptoms. In contrast, GABRA6 rs3219151 showed a significant interaction with social network related life events in case of anxiety and with illness/personal problem-related life events in case of depression. Our results suggest that the psychological impact of different types of recent stress may be differentially modulated by distinct molecular genetic pathways. Furthermore, in case of certain genetic variants, the occurring psychiatric symptom may depend on the type of stress experienced.

Serotonin 2C receptors (5-HT 2C Rs) are implicated in the pathomechanism and treatment of anxiety and depression. Recently, as a new biomarker of depression, alterations in the gamma power of the electroencephalogram (EEG) have been suggested. Chronic treatment with the selective serotonin reuptake inhibitor (SSRI) antidepressant escitalopram has been shown to cause sleep-wake stage-dependent alterations in gamma power. However, despite the antidepressant potency of 5-HT 2C R-antagonists, there is no data available regarding the effects of selective 5-HT 2C R-antagonists on gamma activity. Therefore, we investigate the acute effect of the 5-HT 2C R-antagonist SB-242084 on gamma power in different vigilance stages when given in monotherapy, or in combination with chronic escitalopram treatment. We administered SB-242084 (1 mg/kg, intraperitoneally) or vehicle to EEG-equipped rats after a 21-day-long pretreatment with escitalopram (10 mg/kg/day, via osmotic minipumps) or vehicle. Frontoparietal EEG, electromyogram, and motor activity were recorded during the first 3 h of passive phase, after the administration of SB-242084. Quantitative EEG analysis revealed that acute SB-242084 increased gamma power (30-60 Hz) in light and deep slow-wave sleep, and passive wakefulness. However, in active wakefulness, rapid eye movement sleep, and intermediate stage, no change was observed in gamma power. The profile of the effect of SB-242084 on gamma power was similar to that produced by chronic escitalopram. Moreover, SB-242084 did not alter chronic escitalopram-induced effects on gamma. In conclusion, the similarity in the effect of the 5-HT 2C R-antagonist and chronic SSRI on gamma power provides further evidence for the therapeutic potential of 5-HT 2C Rantagonists in the treatment of depression and/or anxiety.

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Background Racemic ketamine consists of two enantiomers, namely (R)ketamine and (S)ketamine, with distinguishable pharmacological properties. Both enantiomers have been reported to show rapid antidepressant effects in rodents. Currently, the (S)enantiomer has been approved for the treatment of major depression, while (R)ketamine failed to show antidepressant effect in recent clinical studies. Major depressive disorder is frequently characterized by disinhibition of rapid eye movement (REM) sleep and disruption of nonREM (NREM) sleep. Racemic ketamine and most conventional antidepressants affect these parameters. However, it remains largely unknown which enantiomer is responsible for these effects. Methods Here, we compared acute effects of the two ketamine enantiomers (15 mg/kg i.p.) on different sleepwake stages in freely moving, EEGequipped rats. We also evaluated the antidepressant-like activity of the enantiomers in a chronic restraint stress model of depression. Results (S)ketamine, but not (R)ketamine increased REM sleep latency and decreased REM sleep time at 2h and 3h, and increased EEG delta power during NREM sleep. In addition, only (S)-ketamine increased wakefulness and decreased NREM sleep in the first 2 hours. In the forced swimming test only (S)-ketamine decreased the immobility time of chronically stressed rats. Conclusion Effects of the two ketamine enantiomers on rat sleepwake architecture and behavior are markedly different when administered in the same dose. (S)ketamine remarkably affects sleepwake cycle and very likely sleeprelated neuroplasticity, which may be relevant for its antidepressant efficacy. Our results regarding (R)-ketamine’s lack of effect on vigilance and behavior are in line with the recent clinical studies.

The cooperative action of sodium orthovanadate (a putative protein-phosphotyrosine phosphatase inhibitor) and rutin (an effective superoxide scavenger) on the nitric oxide (NO) production of J774A.1 mouse macrophage cells has been investigated. Orthovanadate alone caused a mild but significant increase in NO production of the cells at its highest concentration used (500 microM). Orthovanadate and rutin together caused a significant increase in the nitrite level of the supematants of the J774A.1 cells after a 24-hour incubation period, in a concentration dependent manner. The optimal doses for orthovanadate and rutin were 50 microM and 100 microM, respectively. This cooperative action of rutin and orthovanadate was totally inhibitable by catalase, reduced glutathion, N-acetylcystein, cycloheximide, pyrrolidine dithiocarbamate (a putative NF-kappaB inhibitor), genistein and tyrphostin-AG126 (two protein tyrosine-kinase inhibitors). Superoxide dismutase had no inhibitory effect. Orthovanadate and rutin (only together) could induce the oxidation of 2',7'-dichlorofluorescein-diacetate, a marker of hydrogen peroxide. This effect was inhibitable by reduced glutathion, a hydrogen peroxide specific scavenger. These findings suggest, that orthovanadate can induce the production of NO by J774A.1 macrophages not only by inhibition of protein tyrosine-phosphatases, but, using it with rutin, by increasing the level of hydrogen peroxide in the cells.