Conserved Hypothalamic c-Fos Activation Pattern Induced by the mGlu5 Receptor Antagonist MPEP during Peri-pubertal Development in Mice.

INTRODUCTION: 2-Methyl-6-(phenylethynyl)pyridine (MPEP) is a selective mGlu5 receptor (mGluR5) antagonist intensively studied as potential novel anxiolytic drug. In the adult, MPEP activates stress-related areas, including the paraventricular nucleus of the hypothalamus (PVNh). However, it is unknown if MPEP targets similar structures in the juvenile brain as well. METHODS: Here we examined by immunohistochemical methods the induction pattern of the neuronal activity marker c-Fos by MPEP at peri-pubertal stages (postnatal day P16, P24, P32 and P40) in C57BL6/N mice. RESULTS: Despite the previously reported sharply diminished hypothalamic mGluR5 expression during postnatal development, we found a highly conserved PVNh activation by MPEP together with c-Fos expression in the extended amygdala. Interestingly, MPEP also robustly activated the paraventricular nucleus of the thalamus (PVT) and suprachiasmatic nucleus (SCN), regions associated with the modulation of circadian rhythms. DISCUSSION: These results indicate a conserved activation pattern induced by MPEP in the young vs. adult brain especially in brain areas regulating stress and circadian rhythms and may be of importance regarding the effect of mGluR5 antagonists in the treatment of mood disorders during juvenile development.

Minocycline does not evoke anxiolytic and antidepressant-like effects in C57BL/6 mice.

Minocycline is a broad-spectrum tetracycline antibiotic with multiple actions, including anti-inflammatory and neuroprotective effects, that was proposed as novel treatment for several psychiatric disorders including schizophrenia and depression. However, there are contradictory results regarding antidepressant effects of minocycline in rodent models. Additionally, the possible anxiolytic effect of minocycline is still poorly investigated. Therefore, we aimed to clarify in the present study the influence of minocycline on behavioral correlates of mood disorders in standard tests for depression and anxiety, the Porsolt Forced Swim Test (FST), Elevated O-Maze, Dark-Light Box Test and Openfield Test in adult C57BL/6 mice. We found, unexpectedly, that mice treated with minocycline (20-40mg/kg, i.p.) did not display antidepressant- or anxiolytic-like behavioral changes in contrast to mice treated with diazepam (0.5mg/kg, anxiety tests) or imipramine (20mg/kg, depressive-like behavior). These results are relevant for future studies, considering that C57BL/6 mice, the most widely used strain in pharmacological and genetic animal models, did not react as expected to the treatment regime applied.

Analyses of Gonadoblastoma Y (GBY)-locus and of Y centromere in Turner syndrome patients.

BACKGROUND: Mosaicism with cytogenetically visible Y chromosome is found in 5-6% of Turner Syndrome (TS) patients. Additionally, occult Y-chromosome derived material is increasingly found in patients with monosomy X when using more sensitive molecular techniques. These TS patients are at risk of developing gonadoblastomas when the Y genes presumed to be involved in gonadoblastoma development (Gonadoblastoma-Y-locus; GBY) are present. AIM: To find occult Y-chromosome material in TS patients and to correlate the patient's phenotype to Y-chromosome material. METHODS: We studied 60 TS-patients for presence of the Y chromosome with focus on the Gonadoblastoma Y-locus and its extension in Yp and Yq using sensitive Y centromere and Y gene deletion PCR assays. In addition, we evaluated their individual clinical and auxological characteristics. RESULTS: We identified presence of the GBY-locus in 7 patients (11.7%) including 4 patients without evidence for a Y chromosome in their preceding standard karyotype analyses. Clinical and auxological characteristics were similar in GBY-positive and GBY-negative patients. CONCLUSIONS: Presence of the GBY locus in Turner patients with no indication of the Y chromosome in standard cytogenetic chromosome analysis can be revealed by sensitive molecular PCR assays screening for presence of the Y centromere and the GBY-candidate-genes in proximal Yp11 and Yq11, respectively.

NF-kappaB signalling in cerebral ischaemia.

In acute stroke, neuronal apoptosis and inflammation are considered to be important mechanisms on the road to tissue loss and neurological deficit. Both apoptosis and inflammation depend on gene transcription. We have identified a signalling pathway that regulates transcription of genes involved in apoptosis and inflammation. In a mouse model of focal cerebral ischaemia, there is an induction of the cytokine TWEAK (tumour necrosis factor-like weak inducer of apoptosis) and its membrane receptor Fn14. TWEAK promotes neuronal cell death and activates the transcription factor NF-kappaB (nuclear factor kappaB) through the upstream kinase IKK [IkappaB (inhibitory kappaB) kinase]. In vivo, IKK is activated in neurons. Neuron-specific deletion of the subunit IKK2 or inhibition of IKK activity reduced the infarct size and neuronal cell loss. A pharmacological inhibitor of IKK also showed neuroprotective properties. IKK-dependent ischaemic brain damage is likely to be mediated by NF-kappaB, because neuron-specific inhibition of NF-kappaB through transgenic expression of the NF-kappaB superrepressor was found to reduce the infarct size. In summary, there is evidence that IKK/NF-kappaB signalling contributes to ischaemic brain damage and may provide suitable drug targets for the treatment of stroke.