Molecular neurobiology
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Molecular neurobiology · Oct 2017
Effect of Maternal Stress Prior to Conception on Hippocampal BDNF Signaling in Rat Offspring.
Environmental factors, especially stress, can remain pervasive effects across the lifespan. Traumatic experiences are risk factors for the behavioral and emotional disorders. Since brain-derived neurotrophic factor (BDNF) is the important regulator of neural survival, development, and its genetic and epigenetic alterations which have been linked with several neuropsychiatric disorders, the present study investigated the effect of maternal adulthood stress on molecular changes of BDNF and tyrosine kinase-coupled receptor (TrkB) in the hippocampus of 30-day-old offspring. ⋯ Thirty-day-old male and female pups from SM groups had a significantly more serum corticosterone concentration, DNA methylation levels of BDNF and TrKB, and lower expression of these genes compared to pups from the control groups. Also, male pups from stressed mother exhibited significant anxiety-like behavior compared to male pups from the control mothers. These findings suggest that molecular changes formed by maternal stress experience even before conception persist to the next generation and will negatively influence on phenotypes of offspring.
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Molecular neurobiology · Sep 2017
High-Intensity Swimming Exercise Decreases Glutamate-Induced Nociception by Activation of G-Protein-Coupled Receptors Inhibiting Phosphorylated Protein Kinase A.
Several studies in humans have reported that improved pain control is associated with exercise in a variety of painful conditions, including osteoarthritis, fibromyalgia, and neuropathic pain. Despite the growing amount of experimental data on physical exercise and nociception, the precise mechanisms through which high-intensity exercise reduces pain remain elusive. Since the glutamatergic system plays a major role in pain transmission, we firstly analyzed if physical exercise could be able to decrease glutamate-induced nociception through G-protein-coupled receptor (G-PCR) activation. ⋯ We also verified that glutamate injection increases levels of phosphorylated PKA (p-PKA). High-intensity swimming exercise significantly prevented p-PKA increase. The current data show the direct involvement of the glutamatergic system on the hyponociceptive effect of high-intensity swimming exercise as well as demonstrate that physical exercise can activate multiple intracellular pathways through G-PCR activation, which share the same endogenous mechanism, i.e., inhibition of p-PKA.
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Molecular neurobiology · Sep 2017
Guanosine Prevents Anhedonic-Like Behavior and Impairment in Hippocampal Glutamate Transport Following Amyloid-β1-40 Administration in Mice.
Amyloid-beta (Aβ) peptides are the major neuropathological hallmarks related with Alzheimer's disease (AD). Aβ peptides trigger several biochemical mechanisms of neurotoxicity, including neuroinflammation and glutamatergic neurotransmission impairment. Guanosine is the endogenous guanine-derived nucleoside that modulates the glutamatergic system and the cellular redox status, thus acting as a neuroprotective agent. ⋯ Aβ1-40 decreased GFAP expression in the hippocampal CA1 region, an effect not modified by guanosine. No differences were observed concerning synaptophysin and NeuN immunolabeling. Together, these results show that guanosine prevents memory deficit and anhedonic-like behavior induced by Aβ1-40 that seem to be linked to glutamate transport unbalance and alterations on purine and metabolite levels in mouse hippocampus.
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Prion diseases in humans are neurodegenerative diseases which are caused by an accumulation of abnormal, misfolded cellular prion protein known as scrapie prion protein (PrPSc). Genetic, acquired, or spontaneous (sporadic) forms are known. Pathogenic mutations in the human prion protein gene (PRNP) have been identified in 10-15 % of CJD patients. ⋯ Some non-coding mutations and new mutations in the PrP gene have been identified without clear evidence for their pathogenic significance. In the present review, we provide an updated overview of PRNP mutations, which have been documented in the literature until now, describe the change in the DNA, the family history, the pathogenicity, and the number of described cases, which has not been published in this complexity before. We also provide a description of each genetic prion disease type, present characteristic histopathological features, and the PrPSc isoform expression pattern of various familial/genetic prion diseases.
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Molecular neurobiology · Jul 2017
Guanosine Exerts Neuroprotective Effect in an Experimental Model of Acute Ammonia Intoxication.
The nucleoside guanosine (GUO) increases glutamate uptake by astrocytes and acts as antioxidant, thereby providing neuroprotection against glutamatergic excitotoxicity, as we have recently demonstrated in an animal model of chronic hepatic encephalopathy. Here, we investigated the neuroprotective effect of GUO in an acute ammonia intoxication model. Adult male Wistar rats received an intraperitoneal (i.p.) injection of vehicle or GUO 60 mg/kg, followed 20 min later by an i.p. injection of vehicle or 550 mg/kg of ammonium acetate. ⋯ GUO drastically reduced the lethality rate and the duration of coma. Animals treated with GUO had improved EEG traces, decreased CSF levels of glutamate and alanine, lowered oxidative stress in the cerebral cortex, and increased glutamate uptake by astrocytes in brain slices compared with animals that received vehicle prior to ammonium acetate administration. This study provides new evidence on mechanisms of guanine-derived purines in their potential modulation of glutamatergic system, contributing to GUO neuroprotective effects in a rodent model of by acute ammonia intoxication.