High Fructose Corn Syrup-Moderate Fat Diet Potentiates Anxio-Depressive Behavior and Alters Ventral Striatal Neuronal Signaling

The neurobiological mechanisms that mediate psychiatric comorbidities associated with metabolic disorders such as obesity, metabolic syndrome and diabetes remain obscure. High fructose corn syrup (HFCS) is widely used in beverages and is often included in food products with moderate or high fat content that have been linked to many serious health issues including diabetes and obesity. However, the impact of such foods on the brain has not been fully characterized. Here, we evaluated the effects of long-term consumption of a HFCS-Moderate Fat diet (HFCS-MFD) on behavior, neuronal signal transduction, gut microbiota, and serum metabolomic profile in mice to better understand how its consumption and resulting obesity and metabolic alterations relate to behavioral dysfunction. Mice fed HFCS-MFD for 16 weeks displayed enhanced anxiogenesis, increased behavioral despair, and impaired social interactions. Furthermore, the HFCS-MFD induced gut microbiota dysbiosis and lowered serum levels of serotonin and its tryptophan-based precursors. Importantly, the HFCS-MFD altered neuronal signaling in the ventral striatum including reduced inhibitory phosphorylation of glycogen synthase kinase 3β (GSK3β), increased expression of ΔFosB, increased Cdk5-dependent phosphorylation of DARPP-32, and reduced PKA-dependent phosphorylation of the GluR1 subunit of the AMPA receptor. These findings suggest that HFCS-MFD-induced changes in the gut microbiota and neuroactive metabolites may contribute to maladaptive alterations in ventral striatal function that underlie neurobehavioral impairment. While future studies are essential to further evaluate the interplay between these factors in obesity and metabolic syndrome-associated behavioral comorbidities, these data underscore the important role of peripheral-CNS interactions in diet-induced behavioral and brain function. This study also highlights the clinical need to address neurobehavioral comorbidities associated with obesity and metabolic syndrome.

AMPA Ionotropic Glutamate Receptors Pathogenesis Symptomatic Epilepsy in Gliomas of the Cerebral Hemispheres

The purpose of the research is to study the role of AMPA receptors of glutamate in the mechanisms of the development of epi-lepsy in the patients with gliomas of the big hemispheres of a brain. Materials and methods: 92 patients with gliomas of the big hemispheres of a brain have been examined. Immune enzyme method of semi-quantitative determination of the level of auto-antibodies to NR2A subunit of NMDA and GluR1 subunit of AMPA receptors of glutamate was used. Results: The frequency and clinical features of symptomatic epilepsy have been studied. The reaction of NMDA and of AMPA receptors of glutamate depending on localization and degree of malignance and features of clinical course of the disease, have been examined. Conclusion: A high-technology of patho-morphological research of brain tumors made in recent years has revealed that glial tumors start releasing glutamate by themselves, as their anaplasia level increases, which causes exitotoxical effect in anatomical lines of peritumoral area. Such blastomastoma growth features form specificity of clinical aspect of disease, including epileptic syndrome. It is shown dominative increase the level of auto-antibodies to GluR1 subunit of AMPA receptors of glutamate in the patients with gliomas, current with epileptic syndrome. Under the effect of the tumor on the frontal and temporal share the maximum level of autoantibodies, mainly to GluR1 subunit of AMPA receptors of glutamate is registered.

Down-regulation of Stargazin Inhibits the Enhanced Surface Delivery of α-Amino-3-hydroxy-5-methyl-4-isoxazole Propionate Receptor GluR1 Subunit in Rat Dorsal Horn and Ameliorates Postoperative Pain

Background: Stargazin is the first transmembrane protein known to regulate synaptic targeting of α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptors. However, it is unclear whether regulation of the surface delivery of spinal AMPA receptor subunits by stargazin contributes to postoperative pain development. Methods: Western blot analysis was used to examine changes in the surface delivery of AMPA receptor subunits, GluR1 and GluR2, in rat dorsal horn. The interaction between stargazin and GluR1 and GluR2 was examined by coimmunoprecipitation. Expression of stargazin was suppressed by intrathecal administration of small interfering RNA311. Results: Membrane-bound GluR1, but not GluR2, in ipsilateral dorsal horn was increased at 3 h (1.49 ± 0.15-fold of β-tubulin, mean ± SEM) and 1 day (1.03 ± 0.25) after incision, as compared with that in control rats (naive, 0.63 ± 0.23, P < 0.05, n = 6 per group). The amount of GluR1 coimmunoprecipitated with stargazin was greater at 3 h after incision (1.48 ± 0.31-fold of input) than that in control animals (0.45 ± 0.24, P < 0.05, n = 6 per group). Importantly, the increase in membrane GluR1 at 3 h after incision was normalized to near control level (0.72 ± 0.20-fold of β-tubulin) by pretreatment with intrathecal stargazin small interfering RNA311 (0.87 ± 0.09), but not scrambled small interfering RNA (1.48 ± 0.24) or vehicle (1.25 ± 0.13, P < 0.05, n = 6 per group). Stargazin small interfering RNA311 pretreatment prevented the increase in stargazin–GluR1 interaction and decreased postoperative pain after incision. Conclusions: This study suggests a critical role of stargazin-mediated surface delivery of GluR1 subunit in the development of postoperative pain. A better therapeutic strategy for postoperative pain may involve selectively down-regulating spinal stargazin to inhibit synaptic targeting of GluR1 subunit.

Аlterationdegree of NMDA and AMPA receptors of glutamate in the pathogenesis of the disease and technological peculiarities of surgical treatment of the hemispheric glioma-swith the epileptic syndrome

The development of effective approaches to the treatment of patients with symptomatic tumor epilepsy was determined by the level of our fundamental knowledge of the basic mechanisms of epileptogenesis on cellular and molecular level. 92 patients with gliomas of the cerebral hemisphereswere examined. Immunoenzyme method ofsemiquantitative determination of the level of autoantibodies to NR2A subunit of NMDA and GluR1 subunit of AMPA receptors of glutamate was used. The reaction of NMDA and AMPA glutamate receptors depending on the availability of an epileptic syndrome in the clinical picture of the disease and the extent of radical surgery has been studied. Pre-emptive increase of the level of autoantibodies to GluR1 subunit of AMPA receptors of glutamate in patients with hemispheric gliomaswith epileptic syndrome was demonstrated. It was foundonly the total removal of the tumor reduced significantly the level of autoantibodies to ionotropic glutamate receptors.