[IMMOBILIZATION INDUCED FOS EXPRESSION IN THE MEDIAL AND LATERAL HYPOTHALAMIC AREAS: A LIMITED RESPONSE OF HYPOCRETIN NEURONS]
KISS Alexander
MARCH 20, 2007
Clinical Neuroscience - 2007;60(03-04)
KISS Alexander
MARCH 20, 2007
Clinical Neuroscience - 2007;60(03-04)
[Induction of Fos, a proto-oncogene c-fos protein product, was immunohistochemically examined in the rat hypothalamic neurons 3 h after a single (1×120 min) or repeated (7×120 min) immobilization (IMO) stress. The aim of the present study was to reveal a possible parallelism in the cell activation between the medial and lateral hypothalamic neurons, especially between the stress responsive neurons in the hypothalamic paraventricular nucleus (PVN) and hypocretin (Hcrt) synthesizing neurons, i.e. suspected stress active neurons of the lateral hypothalamus. After IMO, the animals were perfused and their brains processed with immunohistochemistry for Fos or Fos/Hcrt proteins. Acute IMO elicited extensive Fos expression in both the examined areas. Excessive Fos expression was mainly seen in the PVN, while Hcrt neurons failed to show a broad response (appr. 5%) to single IMO. Clear occurrence of Fos signal was also seen in both hypothalamic areas of IMO-habituated rats. However, in these animals, in both areas examined, the number of Fos neurons was considerably suppressed, including the PVN. These results indicate that IMO is able to evoke a concurrent activation of Fos in many medial and lateral hypothalamic neurons. However, the scanty response of Hcrt neurons to acute IMO does not allow to assort them to a distinct IMO stress-responsive neuronal phenotypes of the brain.]
Clinical Neuroscience
[Based on data accumulated regarding the neuroprotective action of Proline-Rich-Peptide-1 (PRP-1, a fragment of neurophysin vasopressin associated hypothalamic glycoprotein consisting of 15 amino acid residues) on neurons survival and axons regeneration and taking into the account that LVV-Hemorphin-7 (LVV-H7, an opioid peptide, widely distributed in different cell types of various tissues of intact rats, including those of the nervous and immune systems) derived from the proteolitic processing of hemoglobin in response to adverse environmental and physiological conditions, possesses the anti-stressor properties, we used histochemistry, immunohistochemistry and electrophysiology to investigate the putative neuroprotective action of Central Asian Cobra Naja naja oxiana snake venom (NOX) on trauma-injured rats. ABC immunohistochemical method and histochemical method on detection of Ca2+- dependent acid phosphatase activity were used for the morpho-functional study. By recording the electrical activity of the signals from the single neurons in and below the SC injury place, NOX venom has been shown to result in the complete restoration of hypothalamic-spinal projections originated from ipsi- and contra-lateral PVN and SON to neurons of SC lumbar part. NOX prevented the scar formation, well observed two months after SC injury in the control rats, resulted in the regeneration of nerve fibers growing through the trauma region, survival of the PRP-1- and LVV-H7-immunoreactive (Ir) neurons, and increase of the PRP-1- and LVV-H7-Ir nerve fibers and astrocytes in the SC lesion region. NOX was suggested to exert the neuroprotective effect, involving the PRP-1 and LVV-H7 in the underlying mechanism of neuronal recovery.]
Clinical Neuroscience
[To test the effect of dehydration on brain atrial natriuretic peptide (ANP) concentrations in areas important to salt appetite, water balance and cardiovascular regulation, we subjected rats to dehydration and rehydration and measured ANP concentration in 18 brain areas, as well as all relevant peripheral parameters. Water deprivation decreased body weight, blood pressure, urine volume, and plasma ANP, while it increased urine and plasma osmolality, angiotensin II, and vasopressin. ANP greatly increased in 17 and 18 brain areas (all cut cerebral cortex) by 24 h. Rehydration for 12 h corrected all changes evoked by dehydration, including elevated ANP levels in brain. We conclude that chronic dehydration results in increased ANP in brain areas important to salt appetite and water balance. These results support a role for ANP as a neuroregulatory substance that participates in salt and water balance.]
Clinical Neuroscience
[Introduction - (-)Deprenyl is an irreversible inhibitor of type B monoamine oxidase (MAO-B), which is now used for treatment of Parkinson’s or Alzheimer’s diseases. Evidence suggests that the neuroprotective effect of deprenyl may not be related exclusively to the inhibition of the enzyme MAO-B. Methods - To test the impact of deprenyl on ischemiainduced changes in vitro, we followed the time course of propidium iodide (PI) uptake as an indicator of neuronal cell death as well as the expression of apoptotic factors in organotypic hippocampal slice cultures exposed to oxygen- glucose deprivation (OGD) for 45 min. Results - The first signs of neuronal death were detected 2 hours after OGD and were extended to all subfields of the hippocampus by 24 hours post-injury. Presence of deprenyl (10-9 M) significantly delayed the cell death induced by the insult. Exposure of control cultures to deprenyl significantly increased the abundance of Bcl-2 and Bcl-xl mRNAs as revealed by RT-PCR. OGD resulted in an elevation of anti-apoptotic factors, while the expression of pro-apoptotic bax remained unchanged. Conclusion - These data suggest that deprenyl is neuroprotective in an in vitro model of ischemia. Although deprenyl upregulates the expression of Bcl-2 under basal conditions, its effect on anti-apoptotic factors is not significantly manifested during OGD.]
Clinical Neuroscience
[Background and purpose - Hypothalamic dopamine (DA), the physiological regulator of pituitary prolactin (PRL) secretion, is synthesized in the neuroendocrine DAergic neurons that projects to the median eminence and the neurointermediate lobe of the pituitary gland. The rate-limiting step of DA biosynthesis is catalyzed by the phosphorylated, therefore activated, tyrosine hydroxylase (TH) that produces L-3,4-dihydroxy- phenylalanine from tyrosine. The aims of our present study were to investigate 1. the effect of local inhibition of the DA biosynthesis in the hypothalamic arcuate nucleus on PRL release, and to get 2. some information whether the phosphorylated TH is the target of enzyme inhibition or not. Methods - A TH inhibitor, α-methyl-p-tyrosine was injected either intracerebro-ventricularly or into the arcuate nucleus of freely moving rats and plasma PRL concentration was measured. Immunohistochemistry, using antibodies raised against to native as well as phosphorylated TH were used to compare their distributions in the arcuate nucleus-median eminence region. Results - Intracerebro-ventricular administration of α-methyl-p-tyrosine has no effect, unlike the intra-arcuatus injection of enzyme inhibitor resulted in a slight but significant elevation in plasma PRL. Parallel with this, the level of DA and DOPAC were reduced in the neurointermediate lobe while no change in norepinephrine concentration can be detected indicating a reduced biosynthesis of dopamine following TH inhibition. On the other hand, systematic application of the α-methyl-p-tyrosine that inhibits TH activity located in DA terminals of the median eminence and the neurointermediate lobe, resulted in the most significant elevation of PRL. Conclusion - Our results suggest that α-methyl-p-tyrosine administered close to the neuroendocrine DAergic neurons was able to inhibit only a small proportion of the TH. Moreover, it also indicate that the majority of the activated TH can be found in the axon terminals of DAergic neurons, therefore, the DA released into the pituitary portal circulation is synthesized at this site.]
Clinical Neuroscience
[Bone marrow derived stem cells (BMDSCs) have been reported to form neurons and supportive cells in the brain. We describe a technique that combines the simplicity of in vitro studies with many of the advantages of in vivo experiments. We cultured mouse brain slices, deposited GFPtagged BMDSCs evenly distributed on their surfaces, and then added test factors to the culture medium. Addition of both SDF-1 and EGF resulted in morphological changes of BMDSC and in the induction of islet-1, a marker of neuroepithelial progenitors. We conclude that organotypic tissue culture (OTC) may allow us to detect the effects of exogenous factors on the differentiation of BMDSCs (or any other type of stem cells) in an environment that may resemble the CNS after brain injury. Once such factors have been identified they could be evaluated for tissue regeneration in more complex, whole animal models.]
Clinical Neuroscience
[Selye pioneered the stress concept that is ingrained in the vocabulary of daily life. This was originally build on experimental observations that divers noxious agents can trigger a similar triad of endocrine (adrenal enlargement), immune (involution of thymus) and gut (gastric erosion formation) responses as reported in a letter to Nature in 1936. Subsequently, he articulated the underlying mechanisms and hypothesized the existence of a “first mediator” in the hypothalamus able to orchestrate this bodily changes. However he took two generations to identify this mediator. The Nobel Laureate, Roger Guillemin, a former Selye’s PhD student, demonstrated in 1955 the existence of a hypothalamic factor that elicited adrenocorticotropic hormone release from the rat pituitary and named it corticotropin releasing factor (CRF). In 1981, Wylie Vale, a former Guillemin’s Ph Student, characterized CRF as 41 amino acid and cloned the CRF1 and CRF2 receptors. This paves the way to experimental studies establishing that the activation of the CRF signaling pathways in the brain plays a key role in mediating the stress-related endocrine, behavioral, autonomic and visceral responses. The unraveling of the biochemical coding of stress is rooted in Selye legacy continues to have increasing impact on the scientific community.]
Clinical Neuroscience
Cognitive dysfunction (CD) is a common non-motor symptom of Parkinson’s disease (PD). Alexithymia is a still poorly understood neuropsychiatric feature of PD. Cognitive impairment (especially visuospatial dysfunction and executive dysfunction) and alexithymia share common pathology of neuroanatomical structures. We hypothesized that there must be a correlation between CD and alexithymia levels considering this relationship of neuroanatomy. Objective – The aim of this study was to evaluate the association between alexithymia and neurocognitive function in patients with PD. Thirty-five patients with PD were included in this study. The Toronto Alexithymia Scale–20 (TAS-20), Geriatric Depression Inventory (GDI) and a detailed neuropsychological evaluation were performed. Higher TAS-20 scores were negatively correlated with Wechsler Adult Intelligence Scale (WAIS) similarities test score (r =-0.71, p value 0.02), clock drawing test (CDT) scores (r=-0.72, p=0.02) and verbal fluency (VF) (r=-0.77, p<0.01). Difficulty identifying feelings subscale score was negatively correlated with CDT scores (r=-0.74, p=0.02), VF scores (r=-0.66, p=0.04), visual memory immediate recall (r=-0.74, p=0.01). VF scores were also correlated with difficulty describing feelings (DDF) scores (r=-0.66, p=0.04). There was a reverse relationship between WAIS similarities and DDF scores (r=-0.70, p=0.02), and externally oriented-thinking (r=-0.77,p<0.01). Executive function Z score was correlated with the mean TAS-20 score (r=-62, p=0.03) and DDF subscale score (r=-0.70, p=0.01) Alexithymia was found to be associated with poorer performance on visuospatial and executive function test results. We also found that alexithymia was significantly correlated with depressive symptoms. Presence of alexithymia should therefore warn the clinicians for co-existing CD.
Hypertension and nephrology
[This consensus document is intended to provide guidance for the effective and efficient treatment of asymptomatic individuals with high uric acid levels and gout patients.]
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Clinical Neuroscience
Alexithymia is associated with cognitive impairment in patients with Parkinson’s disease3.
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Clinical Neuroscience
[Cases of inborn errors of metabolism diagnosed in children with autism ]2.
Clinical Neuroscience
[The first Hungarian patient with Guillain-Barre syndrome after COVID-19]3.
Clinical Neuroscience
Retinal morphological changes during the two years of follow-up in Parkinson’s disease4.
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