Clinical Neuroscience

[SYNAPTIC CONNECTIONS OF GLUTAMATERGIC NERVE FIBRES IN THE RAT SUPRACHIASMATIC NUCLEUS]

KISS József, CSÁKI Ágnes, CSABA Zsolt, HALÁSZ Béla

MARCH 20, 2007

Clinical Neuroscience - 2007;60(03-04)

[Background and purpose - The hypothalamic suprachiasmatic nucleus functioning as the principal circadian pacemaker in mammals, has a rich glutamatergic innervation. Nothing is known about the terminations of the glutamatergic fibres. The aim of the present investigations was to study the relationship between glutamatergic axon terminals and vasoactive intestinal polypeptide (VIP), GABA and arginine-vasopressin (AVP) neurons in the cell group. Methods - Double label immunocytochemistry was used and the brain sections were examined under the electron microscope. Vesicular glutamate transporter type 2 was applied as marker of the glutamatergic elements. Results - Glutamatergic fibers were detected in synaptic contact with GABAergic, VIP- and AVP-positive neurons forming asymmetric type of synapses. Conclusion - The findings are the first data on the synaptic contacts of glutamatergic axon terminals with neurochemically identified neurons in the suprachiasmatic nucleus.]

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Clinical Neuroscience

[PROTECTIVE ACTION OF SNAKE VENOM NAJA NAJA OXIANA AT SPINAL CORD HEMISECTION]

ABRAHAMYAN S. Silva, MELIKSETYAN B. Irina, CHAVUSHYAN A. Vergine, ALOYAN L. Mery, SARKISSIAN S. John

[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

[CENTRAL ATRIAL NATRIURETIC PEPTIDE IN DEHYDRATION]

BAHNER Udo, GEIGER Helmut, PALKOVITS Miklós, LENKEI Zsolt, LUFT C. Friedrich, HEIDLAND August

[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

[OXYGEN-GLUCOSE DEPRIVATION-INDUCED CHANGES IN ORGANOTYPIC CULTURES OF THE RAT HIPPOCAMPUS]

BALI Balázs, NAGY Zoltán, KOVÁCS J. Krisztina

[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

[EFFECT OF LOCAL (INTRACEREBRAL AND INTRACEREBROVENTRICULAR) ADMINISTRATION OF TYROSINE HYDROXYLASE INHIBITOR ON THE NEUROENDOCRINE DOPAMINERGIC NEURONS AND PROLACTIN RELEASE]

BODNÁR Ibolya, HECHTL Dániel, SZÉKÁCS Dániel, OLÁH Márk, NAGY M. György

[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

[USING BRAIN SLICE CULTURES OF MOUSE BRAIN TO ASSESS THE EFFECT OF GROWTH FACTORS ON DIFFERENTIATION OF BONE MARROW DERIVED STEM CELLS]

BRATINCSÁK András, LONYAI Anna, SHAHAR Tal, HANSEN Arne, TÓTH E. Zsuzsanna, MEZEY Éva

[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.]

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[GLUTAMATERGIC PHENOTYPE OF HYPOTHALAMIC NEUROSECRETORY SYSTEMS: A NOVEL ASPECT OF CENTRAL NEUROENDOCRINE REGULATION]

HRABOVSZKY Erik, LIPOSITS Zsolt

[While three decades ago, the co-existence of classical neurotransmitters and peptide neuromodulators in a single neuronal cell was considered to be rather exceptional, the phenomenon that neurons have a complex transmitter phenotype now appears to be the general rule. Parvicellular and magnocellular neurosecretory systems consist of neuronal cells which are specialized in secreting peptide neurohormones into the blood-stream to regulate hypophyseal functions. This mini-review, dedicated to the memory of Mariann Fodor, summarizes the current knowledge about the classical neurotransmitter content of different hypothalamic neurosecretory systems, with a special focus on the occurrence and putative functions of glutamate in parvicellular and magnocellular neurosecretory cells.]

Clinical Neuroscience

Evaluation of the effectiveness of transforaminal epidural steroid injection in far lateral lumbar disc herniations

EVRAN Sevket, KATAR Salim

Far lateral lumbar disc herniations (FLDH) consist approximately 0.7-12% of all lumbar disc herniations. Compared to the more common central and paramedian lumbar disc herniations, they cause more severe and persistent radicular pain due to direct compression of the nerve root and dorsal root ganglion. In patients who do not respond to conservative treatments such as medical treatment and physical therapy, and have not developed neurological deficits, it is difficult to decide on surgical treatment because of the nerve root damage and spinal instability risk due to disruption of facet joint integrity. In this study, we aimed to evaluate the effect of transforaminal epidural steroid injection (TFESI) on the improvement of both pain control and functional capacity in patients with FLDH. A total of 37 patients who had radicular pain caused by far lateral disc herniation which is visible in their lumbar magnetic resonance imaging (MRI) scan, had no neurological deficit and did not respond to conservative treatment, were included the study. TFESI was applied to patients by preganglionic approach. Pre-treatment Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI) scores of the patients were compared with the 3rd week, 3rd month and 6th month scores after the procedure. The mean initial VAS score was 8.63 ± 0.55, while it was 3.84 ± 1.66, 5.09 ± 0.85, 4.56 ± 1.66 at the 3rd week, 3rd month and 6th month controls, respectively. This decrease in the VAS score was found statistically significant (p = 0.001). ODI score with baseline mean value of 52.38 ± 6.84 was found to be 18.56 ± 4.95 at the 3rd week, 37.41 ± 14.1 at the 3rd month and 34.88 ± 14.33 at the 6th month. This downtrend of pa­tient’s ODI scores was found statistically significant (p = 0.001). This study has demonstrated that TFESI is an effective method for gaining increased functional capacity and pain control in the treatment of patients who are not suitable for surgical treatment with radicular complaints due to far lateral lumbar disc hernia.

Clinical Neuroscience

Autonomic nervous system may be affected after carpal tunnel syndrome surgery: A possible mechanism for persistence of symptoms after surgery

ONDER Burcu, KELES Yavuz Betul

After carpal tunnel surgery, some patients report complaints such as edema, pain, and numbness. Purpose – The aim of this study was to evaluate autonomic nervous system function in patients with a history of carpal tunnel surgery using sympathetic skin response (SSR). Thirty three patients (55 ±10 years old) with a history of unilateral operation for carpal tunnel syndrome were included in the study. The SSR test was performed for both hands. Both upper extremities median and ulnar nerve conduction results were recorded. A reduced amplitude (p=0.006) and delayed latency (p<0.0001) were detected in the SSR test on the operated side compared to contralateral side. There was no correlation between SSR and carpal tunnel syndrome severity. Although complex regional pain syndrome does not develop in patients after carpal tunnel surgery, some of the complaints may be caused by effects on the autonomic nervous system.

Clinical Neuroscience

Cyanocobalamin and cholecalciferol synergistically improve functional and histopathological nerve healing in experimental rat model

ALBAY Cem, ADANIR Oktay, AKKALP Kahraman Asli, DOGAN Burcu Vasfiye, GULAEC Akif Mehmet, BEYTEMUR Ozan

Introduction - Peripheral nerve injury (PNI) is a frequent problem among young adults. Hopefully, regeneration can occur in PNI unlike central nervous system. If nerve cut is complete, gold standard treatment is surgery, but incomplete cuts have been tried to be treated by medicines. The aim of the study was to evaluate and compare clinical and histopathological outcomes of independent treatment of each of Vitamin B12 (B12) and Vitamin D3 (D3) and their combination on sciatic nerve injury in an experimental rat model. Materials and methods - Experimental animal study was performed after the approval of BEH Ethics Committee No. 2015/10. 32 rats were grouped into four (n=8) according to treatment procedures, such as Group 1 (controls with no treatment), Group 2 (intraperitoneal 1 mg/kg/day B12), Group 3 (oral 3500 IU/kg/week D3), Group 4 (intraperitoneal 1 mg/kg/day B12+ oral 3500 IU/kg/week D3). Sciatic Functional Index (SFI) and histopathological analysis were performed. Results - SFIs of Group 2, 3, 4 were statistically significantly higher than controls. Group 2 and 3 were statistically not different, however Group 4 was statistically significantly higher than others according to SFI. Axonal degeneration (AD) in all treatment groups were statistically significantly lower than in Group 1. AD in Group 4 was significantly lower than in Group 2 and 3; there was no significant difference between Group 2 and 3. There was no significant difference between Group 1,2 and 3 in Axonolysis (A). But A of Group 4 was significantly very much lower than all others. Oedema- inflammation (OE-I) in all treatment groups were significantly lower than in Group 1; there was no significant difference between Group 2 and group 4. OE-I in Group 2 and 4 were significantly lower than in Group 3. There were no significant differences between Group 1, 2 and 3 in damage level scores; score of Group 4 was significantly lower than of Group 1. Conclusions - B12 and D3 were found effective with no statistically significant difference. But combined use of B12 and D3 improve nerve healing synergistically. We recommend combined use of B12 and D3 after PNI as soon as possible.