We previously provided evidence supporting the existence of a novel leptin-independent body weight homeostat ("the gravitostat") that senses body weight and then initiates a homeostatic feed-back regulation of body weight. We, herein, hypothesize that this feed-back regulation involves a CNS mechanism. To identify populations of neurones of importance for the putative feed-back signal induced by increased loading, high-fat diet-fed rats or mice were implanted intraperitoneally or subcutaneously with capsules weighing ∼15% (Load) or ∼2.
View Article and Find Full Text PDFPhilos Trans R Soc Lond B Biol Sci
October 2023
Body weight is tightly regulated when outside the normal range. It has been proposed that there are individual-specific lower and upper intervention points for when the homeostatic regulation of body weight is initiated. The nature of the homeostatic mechanisms regulating body weight at the lower and upper ends of the body weight spectrum might differ.
View Article and Find Full Text PDFEcto-5'-nucleotidase (eN), a membrane rate-limiting enzyme of the purine catabolic pathway, catalyzes the conversion of AMP to adenosine involved in the regulation of many brain physiological and pathological processes. Since gender fundamentally determines hormonal milieu in the body and brain, it is reasonable to assume that sex differences in the activity of various signaling systems, including adenosine, may be generated by gonadal steroids. Thus, we examined expression of eN as a component of adenosine signaling system in the basal state in cerebral cortex and hippocampus of male and female rats at gene, protein and functional level, as well as in the state of gonadal hormone deprivation, induced by ovariectomy (OVX), whereas impact of steroid hormones was explored after repeated administration of 17α-estradiol, 17β-estradiol and progesterone for seven consecutive days.
View Article and Find Full Text PDFAlthough a substantial number of pre-clinical and experimental studies have investigated effects of 17β-estradiol, its precise molecular mechanism of action in the early state of chronic cerebral hypoperfusion remains controversial. The present study attempted to verify whether post-ischemic estradiol treatment (33.3 μg/kg for seven consecutive days) affects previously reported number of hippocampal apoptotic cells and amount of DNA fragmentation characteristic for apoptosis as well as the expression of key elements within synaptosomal Akt and Erk signal transduction pathways (NF-κB, Bax, Bcl-2, cytochrome C, caspase 3, and PARP).
View Article and Find Full Text PDFThe present study attempted to investigate how chronic cerebral hypoperfusion (CCH) and repeated low-dose progesterone (P) treatment affect gene and protein expression, subcellular distribution of key apoptotic elements within protein kinase B (Akt) and extracellular signal-regulated kinases (Erk) signal transduction pathways, as well as neurodegenerative processes and behavior. The results revealed the absence of Erk activation in CCH in cytosolic and synaptosomal fractions, indicating a lower threshold of Akt activation in brain ischemia, while P increased their levels above control values. CCH induced an increase in caspase 3 (Casp 3) and poly (ADP-ribose) polymerase (PARP) gene and protein expression.
View Article and Find Full Text PDFUnlabelled: The antibody response to proteins may be modulated by the presence of preexisting antigen-specific antibodies and the formation of immune complexes (ICs). Effects such as a general increase or decrease of the response as well as epitope-specific phenomena have been described. In this study, we investigated influences of IC immunization on the fine specificity of antibody responses in a structurally well-defined system, using the envelope (E) protein of tick-borne encephalitis (TBE) virus as an immunogen.
View Article and Find Full Text PDFDisturbance in blood circulation is associated with numerous pathological conditions characterized by cognitive decline and neurodegeneration. Activation of pro-apoptotic signaling previously detected in the synaptosomal fraction may underlie neurodegeneration in the prefrontal cortex of rats submitted to permanent bilateral common carotid arteries occlusion (two-vessel occlusion, 2VO). 17β-Estradiol (E) exerts potent neuroprotective effects in the brain affecting, among other, ischemia-induced pathological changes.
View Article and Find Full Text PDFUnlabelled: Tick-borne encephalitis (TBE) virus is an important human-pathogenic flavivirus endemic in large parts of Europe and Central and Eastern Asia. Neutralizing antibodies specific for the viral envelope protein E are believed to mediate long-lasting protection after natural infection and vaccination. To study the specificity and individual variation of human antibody responses, we developed immunoassays with recombinant antigens representing viral surface protein domains and domain combinations.
View Article and Find Full Text PDFChronic exposure to stress contributes to the etiology of mood disorders, and the liver as a target organ of antidepressant and antipsychotic drug metabolism is vulnerable to drug-induced toxicity. We investigated the effects of chronic administration of fluoxetine (15mg/kg/day) or clozapine (20mg/kg/day) on liver injury via the measurement of liver enzymes, oxidative stress and histopathology in rats exposed to chronic social isolation (21days), an animal model of depression, and controls. The activity of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST), the liver content of carbonyl groups, malonyldialdehyde (MDA), reduced glutathione (GSH), cytosolic glutathione S-transferase (GST) and nitric oxide (NO) metabolites were determined.
View Article and Find Full Text PDFChronic oxidative stress plays an important role in depression. The aim of present study was to examine the stress-induced changes in serum corticosterone (CORT) levels, cytosolic protein carbonyl groups, malondialdehyde (MDA), reduced glutathione (GSH), nitric oxide (NO) and total superoxide dismutase (SOD) activity in the prefrontal cortex versus hippocampus of male Wistar rats exposed to acute (2 h of immobilization or cold), chronic (21d of social isolation) stress, and their combination (chronic + acute stress). The subcellular distribution of nuclear factor-κB (NF-κB) and cytosolic cyclooxygenase 2 (COX-2) protein expressions were also examined.
View Article and Find Full Text PDFAluminum hydroxide is the most widely used adjuvant in human vaccines and serves as a potent enhancer of antibody production. Its stimulatory effect strongly depends on the adsorption of the antigen to the adjuvant, which may influence antigen presentation and, as a consequence, the fine specificity of antibody responses. Such variations can have functional consequences and can modulate the effectiveness of humoral immunity.
View Article and Find Full Text PDFJ Neural Transm (Vienna)
January 2014
Stress-related glucocorticoids and glutamate release has been implicated in depression. Glutamate neurotoxicity is mediated, in part, by the production of nitric oxide via nitric oxide synthase (NOS) isoforms and mitochondrial damage. We previously reported that chronic social isolation stress triggers proapoptotic signaling in the rat prefrontal cortex, but not in the hippocampus.
View Article and Find Full Text PDFThe live attenuated yellow fever (YF) vaccine has an excellent record of efficacy and one dose provides long-lasting immunity, which in many cases may last a lifetime. Vaccination stimulates strong innate and adaptive immune responses, and neutralizing antibodies are considered to be the major effectors that correlate with protection from disease. Similar to other flaviviruses, such antibodies are primarily induced by the viral envelope protein E, which consists of three distinct domains (DI, II, and III) and is presented at the surface of mature flavivirions in an icosahedral arrangement.
View Article and Find Full Text PDFExposure of an organism to stress, results in oxidative stress and increased nitric oxide (NO) production in the brain. The role of the processes caused by chronic stress in the prefrontal cortex has not been fully investigated. Considering that chronic stress increases NO production by the enzyme nitric oxide synthase (NOS), we examined the cytosolic neuronal (nNOS) or inducible (iNOS) protein levels in the prefrontal cortex of rats exposed to 21d of chronic social isolation stress, an animal model of depression, alone or in combination with 2h of acute immobilization or cold (4°C) stress (combined stress).
View Article and Find Full Text PDFThe hippocampus plays a central role in stress-related mood disorders. The effects of acute vs. chronic stress on the integrity of hippocampal circuitry in influencing the vulnerability to, or resiliency against, neuronal injury are poorly understood.
View Article and Find Full Text PDFIntroduction: Specific morphological and functional characteristics of athletes have a significant role in determining athletes' sports results and can be also used to assess the athlete's individual potential.
Objective: The aim of the study was to compare anthropometric characteristics and cardiovascular parameters in trained subjects to those of untrained subjects.
Methods: A total number of 25 trained (17.
Mitochondrial dysfunction has been implicated in several psychiatric disorders, including depression. Given that the B-cell-lymphoma 2 (Bcl-2) protein family plays a role in the regulation of mitochondrial apoptotic pathway, we hypothesized that ratio of proapoptotic to antiapoptotic proteins (e.g.
View Article and Find Full Text PDFJ Neural Transm (Vienna)
November 2012
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.
View Article and Find Full Text PDFMitochondria are central integrators and transducers of proapoptotic signals for neuronal apoptosis. The tumor suppressor protein p53 can trigger apoptosis independently of its transcriptional activity, through subcellular translocation of cytochrome c and caspase activation. To define better the proapoptotic role of p53 under various stress conditions, we investigated the protein levels of p53 and cytochrome c in mitochondrial and cytosolic fractions, as well as caspase-3 activation and apoptosis, in the prefrontal cortex and hippocampus of male Wistar rats subjected to acute, chronic, or combined stressors.
View Article and Find Full Text PDFExposure to different stressors initiates generation of reactive oxygen species (ROS), which create harmful environment for cellular macromolecules. Superoxide dismutases (SODs) represent the first line of antioxidant defense. Hence, any alternation in their function might be potentially damaging.
View Article and Find Full Text PDFFactors controlling the dominance of antibody responses to specific sites in viruses and/or protein antigens are ill defined but can be of great importance for the induction of potent immune responses to vaccines. West Nile virus and other related important human-pathogenic flaviviruses display the major target of neutralizing antibodies, the E protein, in an icosahedral shell at the virion surface. Potent neutralizing antibodies were shown to react with the upper surface of domain III (DIII) of this protein.
View Article and Find Full Text PDFForecasting disease susceptibility requires detection of maladaptive signatures prior to onset of overt symptoms. A case-in-point are cardiac ATP-sensitive K+ (K(ATP)) channelopathies, for which the substrate underlying disease vulnerability remains to be identified. Resolving molecular pathobiology, even for single genetic defects, mandates a systems platform to reliably diagnose disease predisposition.
View Article and Find Full Text PDFKCNJ11 null mutants, lacking Kir6.2 ATP-sensitive K(+) (K(ATP)) channels, exhibit a marked susceptibility towards hypertension (HTN)-induced heart failure. To gain insight into the molecular alterations induced by knockout of this metabolic sensor under hemodynamic stress, wild-type (WT) and Kir6.
View Article and Find Full Text PDFManganese superoxide dismutase (MnSOD) is the major antioxidant in mitochondria that protect brain from neuroendocrine stress. Although MnSOD is localized in the mitochondria, the immediate subcellular distribution of MnSOD protein level in the prefrontal cortex and hippocampus of Wistar male rats exposed to acute stressors immobilization or cold, chronic stress isolation or their combinations (acute/chronic) have not been studied. Western immunoblotting revealed that acute immobilization stress resulted in an increase in mitochondrial MnSOD protein level, whereas chronic isolation compromises MnSOD protein level.
View Article and Find Full Text PDFThe human hydroxysteroid sulfotransferase (SULT) 2B1 gene is a member of the cytosolic SULT gene superfamily. The two SULT2B1 isoforms, SULT2B1a and SULT2B1b, are encoded by a single gene as a result of alternative transcription initiation and alternative splicing. SULT2B1b catalyzes the sulfonation of 3beta-hydroxysteroid hormones and cholesterol, whereas SULT2B1a preferentially catalyzes pregnenolone sulfonation.
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