5-HT1A receptor-mediated apoptosis: death by JNK?

Repressor element 1 silencing transcription factor /neuron-restrictive silencing factor (REST/NRSF) in social stress and depression

Extreme stress is closely linked with symptoms of depression. Chronic social stress can cause structural and functional changes in the brain. These changes are associated with dysfunction of neuroprotective signalling that is necessary for cell survival, growth, and maturation. Reduced neuronal numbers and volume of brain regions have been found in depressed patients, which may be caused by decreased cell survival and increased cell death. Elucidating the mechanism underlying the degeneration of the neuroprotective system in social stress-induced depression is important for developing neuroprotective measures. The Repressor Element 1 Silencing Transcription Factor (REST) also known as Neuron-Restrictive Silencing Factor (NRSF) has been reported as a neuroprotective molecule in certain neurological disorders. Decreased expression levels of REST/NRSF in the nucleus can induce death-related gene expression, leading to neuronal death. Under physiological stress conditions, REST/NRSF over expression is known to activate neuronal survival in the brain. Alterations in REST/NRSF expression in the brain has been reported in stressed animal models and in the post-mortem brain of patients with depression. Here, we highlight the neuroprotective function of REST/NRSF and discuss dysregulation of REST/NRSF and neuronal damage during social stress and depression.

[Tthe efficacy and safety of drug therapy divaza in patients with chronic cerebral ischemia]

AIM

To evaluate the efficacy and safety of divazа in the treatment of cognitive and emotional disorders in patients with chronic cerebral ischemia (CCI) based on clinical findings and laboratory markers of endothelial dysfunction.

MATERIAL AND METHODS

Thirty patients with CCI, aged 40 to 70 years, were examined. All patients were treated with divazа (2 tablets 3 times a day) for 12 weeks. Cognitive functions and markers of endothelial dysfunction (the activity of endothelial NO-synthase (eNOS), the number of circulating desquamated endothelial cells in blood plasma) were measured at baseline and after treatment.

RESULTS

Divazа significantly reduced the severity of clinical symptoms and had a positive effect on endothelial dysfunction normalizing the tone of cerebral vessels and preventing deendotheliazation.

CONCLUSION

The use of divazа resulted in clinical improvement and normalization of markers of endothelial dysfunction as well.

Effect of Buspirone, Fluoxetine and 8-OH-DPAT on Striatal Expression of Bax, Caspase-3 and Bcl-2 Proteins in 6-Hydroxydopamine-Induced Hemi-Parkinsonian Rats

PURPOSE

The exact pathogenesis of sporadic parkinson's disease (PD) is still unclear. Numerous evidences suggest involvement of apoptosis in the death of dopaminergic neurons. In this study we investigated the effect of sub-chronic administration of buspirone, fluoxetine and 8-hydroxy-2-[di-n-propylamino]tetralin (8-OH-DPAT) in 6-hydroxydopamine (6-OHDA)-lesioned rats and assayed striatal concentrations of apoptotic (Bax, Caspase3) and anti-apoptotic (Bcl-2) proteins.

METHODS

6-OHDA (8μg/2μl/rat) was injected unilaterally into the central region of the substantia nigra pars copmacta (SNc) of male Wistar rats and then, after 21 days lesioned rats were treated with intraperitonel (i.p) 1 mg/kg injections of buspirone, fluoxetine and 8-OH-DPAT for 10 consecutive days. Striatum of rats was removed at tenth day of drugs administration and were analyzed by western blotting method to measure Bax, caspase3 and Bcl-2 expression.

RESULTS

The results showed that the expression of Bax and caspase3 proteins was increased three weeks after 6-OHDA injection while they were decreased significantly in parkinsonian rats which were treated by buspirone, fluoxetine and 8-OH-DPAT. Bcl-2 was decreased and increased in parkinsonian rats and parkinsonian rats treated with buspirone, fluoxetine and 8-OH-DPAT, respectively.

CONCLUSION

Our study indicates that sub-chronic administration of serotonergic drugs such as buspirone, fluoxetine and 8-OH-DPAT restores striatal concentration of apoptotic and anti-apoptotic factors to the basal levels of normal non-lesioned rats. We suggest that these drugs can be used as a potential adjunctive therapy in PD through attenuating neuronal apoptotic process.

Enantiomeric resolution of [(2,2-diphenyl-1,3-dioxolan-4-yl)methyl](2-phenoxyethyl)amine, a potent α1and 5-HT1Areceptor ligand: an in vitro and computational study

Enantioseparation and stereoselective synthesis of (1), a potent 5-HT_1AR ligand, were performed. Surprisingly, the enantiomers proved to be equipotent.

Chronic isolation stress compromises JNK/c-Jun signaling in rat brain

The c-Jun NH2-terminal kinases (JNKs) are important stress-responsive kinases. They regulate cellular activities by sequential phosphorylation and activation through a mitogen-activated protein kinase cascade, whereas JNKs activation is altered in response to various stressors. In the present study, we used immunoblotting to assess the effect of 21 day of social isolation as the chronic stressor, either sole and in combination with 2 h of acute immobilization or cold (4°C) stress on circulating corticosterone level and phosphorylation status of p46 (phospho-p46/total p46) and p54 (phospho-p54/total p54) JNK isoforms in the cytosolic and nuclear fraction of the prefrontal cortex and hippocampus of male Wistar rats. Also, the phosphorylation status of JNK nuclear down-stream target c-Jun (p-c-Jun/c-Jun) on Ser63 was examined. Both acute stressors with elevated CORT levels led to increased phosphorylation status of cytosolic p54 JNK isoforms but not p46 JNK isoforms only in the hippocampus and no change in phosphorylation status of c-jun in both brain regions. Chronic isolation with unaltered CORT level and reduced responsiveness to novel acute stressors, led to unchanged or reduced phosphorylation status of p46 and p54 JNK isoforms in both fractions and both brain regions, whereas the decrease of c-Jun phosphorylation status was found only in the prefrontal cortex. Our results suggest that compromised JNKs activation following chronic isolation may lead to interruption of JNK signaling, which could be related with neuropsychiatric disorders such as depression or long-lasting neuronal remodeling.