Clinical Neuroscience

[PITUITARY ATRIAL NATRIURETIC PEPTIDE OF PARAVENTRICULAR NUCLEUS ORIGIN]

FODOR Mariann1, MAKARA B. Gábor1, PALKOVITS Miklós2

MARCH 20, 2007

Clinical Neuroscience - 2007;60(03-04)

[Atrial natriuretic peptide-synthesizing neurons in the hypothalamic paraventricular nucleus constitute the major sources of ANP in the three lobes of the pituitary gland. Complete transection of the pituitary stalk eliminated 93% of ANP from the intermediate lobe, 47 and 77% from the anterior and the posterior lobes, respectively. Meantime, increased levels of immunoreactive ANP were measured in the median eminence, due to the accumulation of the peptide in the transected axons centrally to the transected stalk and in the paraventricular nucleus. It is likely that ANP neurons in the paraventricular nucleus innervate the pituitary, but those in the periventricular (median) preoptic nucleus and the organum vasculosum laminae terminalis may not contribute to the ANP innervation of the pituitary gland.]

AFFILIATIONS

  1. Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest
  2. Neuromorphological and Neuroendocrine Research Laboratory, Hungarian Academy of Sciences and Semmelweis University, Budapest

COMMENTS

0 comments

Further articles in this publication

Clinical Neuroscience

[ACTIVATED SOMATOSTATIN TYPE 2 RECEPTORS TRAFFIC IN VIVO FROM DENDRITES TO THE TRANS-GOLGI NETWORK]

CSABA Zsolt, PASCAL Dournaud

[Background and purpose - Understanding the trafficking of G-protein-coupled receptors is of particular importance. In the central nervous system, although some Gprotein- coupled receptors were reported to internalize in vivo, little is known about their trafficking downstream of the endocytic event. Methods - The distribution of the major somatostatin receptor subtype, the sst2, was monitored in the hippocampus using immunofluorescence from 10 minutes to seven days after in vivo injection of the receptor agonist octreotide. Results - From 10 min to 3 h after agonist injection, intensity of receptor immunoreactivity gradually decreased in the molecular layer of dentate gyrus and in the strata oriens and radiatum of CA1. Concomitantly, in the granular and pyramidal layers, small spherical immunofluorescent particles became apparent in perikarya, shortly after agonist stimulation (i.e. 30 min, 60 min). After longer survival times (i.e. 3 h, 6 h, 24 h), immunolabeling was confined to larger, intensely-stained intracytoplasmic vesicles. From 48 h to 7 d after agonist injection, distribution and intensity of sst2 receptor immunoreactivity became similar to that of control animals. The sst2 receptor labeling extensively colocalized with TGN38 and syntaxin 6 after OCT injection. Colocalization with trans-Golgi markers was observed as soon as 1 h after OCT injection and still present 24 h after. By contrast, colocalization with the endoplasmic reticulum marker PDI and the cis-Golgi marker GM130 was never observed. Conclusions - Our results suggest that upon agonist stimulation, dendritic receptors are retrogradely transported to a trans-Golgi network domain enriched in the t-SNARE syntaxin-6 and TGN38 proteins before recycling.]

Clinical Neuroscience

[Editor’s note]

RAJNA Péter

Clinical Neuroscience

[CHARACTERIZATION OF SPECIFIC SUCCINATE BINDING SITE IN BRAIN SYNAPTIC MEMBRANES]

MOLNÁR Tünde, FEKETE Kútiné Erzsébet, KARDOS Julianna, PALKOVITS Miklós

[A synaptic receptor for gamma-hydroxybutyric acid (GHB) - a naturally occuring metabolite of succinic acid1 - interacting succinate has been disclosed in rat and human nucleus accumbens (NA) subcellular fractions2, but the molecular properties of this recognition site were not characterised. To address the presumed recognition site for succinate, the pharmacological profile of [3H]succinate binding to synaptic membranes prepared from rat forebrain and human NA samples has been investigated. Specific [3H]succinate binding sites in the human NA synaptic membrane fraction showed a strong pH-dependence and were characterized by binding of succinate (IC50,SUCC=2.9±0.6 µM), GHB (IC50,GHB=2.1±1.3 µM) and gap junction blocker carbenoxolone (IC50,CBX=7.1±5.8 µM). A similar [3H]succinate binding profile was found in rat forebrain synaptic membrane fractions. We conclude the existence of a pHo-dependent synaptic membrane binding site for the intermediary metabolite succinate. The pharmacological properties of this recognition site may possibly suggest the existence of a hemichannel-like target protein for succinate.]

Clinical Neuroscience

[BRAIN INSULIN SIGNALLING IN THE REGULATION OF ENERGY BALANCE AND PERIPHERAL METABOLISM]

MICHAELA Diamant

[The unparalleled global rates of obesity and type 2 diabetes, together with the associated cardiovascular morbidity and mortality, are referred to as the "diabesity pandemic". Changes in lifestyle occurring worldwide, including the increased consumption of high-caloric foods and reduced exercise, are regarded as the main causal factors. Central obesity and insulin resistance have emerged as important linking components. Understanding the aetiology of the cluster of pathologies that leads to the increased risk is instrumental in the development of preventive and therapeutic strategies. Historically, skeletal muscle, adipose tissue and liver were regarded as key insulin target organs involved in insulinmediated regulation of peripheral carbohydrate, lipid and protein metabolism. The consequences of impaired insulin action in these organs were deemed to explain the functional and structural abnormalities associated with insulin resistance. The discovery of insulin receptors in the central nervous system, the detection of insulin in the cerebrospinal fluid after peripheral insulin administration and the well-documented effects of intracerebroventricularly injected insulin on energy homeostasis, have identified the brain as an important target for insulin action. In addition to its critical role as a peripheral signal integrating the complex network of hypothalamic neuropeptides and neurotransmitters that influence parameters of energy balance, central nervous insulin signalling is also implicated in the regulation of peripheral glucose metabolism. This review summarizes the evidence of insulin action in the brain as part of the multifaceted circuit involved in the central regulation of energy and glucose homeostasis, and discuss the role of impaired central nervous insulin signalling as a pathogenic factor in the obesity and type 2 diabetes epidemic.]

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.]

All articles in the issue

Related contents

Clinical Neuroscience

Investigation of risk factors, topographic location and stroke mechanisms of unilateral isolated and posterior cerebral ARTERY thalamic infarcts

GÖKCAL Elif, SENGUL Yildizhan, USLU Ilgen Ferda

Aim - In this study, we aimed to examine the risk factors, topographic features and stroke mechanisms of acute ischemic unilateral infarcts of thalamus. Methods - Patient with isolated thalamic infarct and those with posterior cerebral artery (PCA) infarction who were admitted to our hospital between January 2014 and January 2017 with acute unilateral thalamic infarction (TI) were included in this study (isolated thalamic infarction/ isolated TI; thalamic and posterior cerebral artery infarction/PCA+TI). Demographic characteristics and vascular risk factors of the patients were determined. Thalamic infarct areas were recorded topographically as anterior, posteromedial, ventrolateral, posterolateral, more than one area, and variant areas. Stroke mechanism was determined according to the criteria of „Trial of Org 10172 in Acute Stroke Treatment” (TOAST). Patients with isolated TI and PCA TI were compared according to risk factors, stroke mechanism and infarct topography. Results - Forty-three patients with a mean age of 63.3 ± 14.5 years were included in the study. Twenty-eight patients (60.1%) were found to have isolated TI and the remaining 15 patients (34.9%) had PCA+TI. 32.1% of patients with isolated TI had sensory symptoms on presentation, and 60% of patients with PCA-TI had sensorimotor symptoms. The mean age, the mean score on National Institutes of Health Stroke Scale (NIHSS) and the mean frequency of atrial fibrillation were higher in PCA+TI patients than in isolated-TI patients (p: 0.04, p: 0.004, p: 0.02 respectively). 32.6% of the patients had ventrolateral, 30.2% had posteromedial involvement. Ventrolateral topography was seen in 46.7% of the PCA+TI patients, while posteromedial topography was seen in 39.3% of the isolated-TI patients. 53.6% of the isolated-TI had small vessel disease etiology, while 40% of the PCA+TI had cardioembolic etiology, and the other 40% had large artery atherosclerosis. Conclusion - Our study showed that the most ommon stroke mechanism in patients with thalamic infarction is the small vessel disease. Isolated TI and PCA+TI patients differ in terms of etiologic mechanism and infarct topography. Variant territorial involvement and multiple area involvements can be quite common in thalamic infarcts.

Lege Artis Medicinae

[NEW WAYS IN THE MANAGEMENT OF RHEUMATOID ARTHRITIS IN HUNGARY]

GERGELY Péter, POÓR Gyula

[Rheumatoid arthritis is an autoimmune rheumatic condition of unknown origin. Due to its high prevalence, incompletely solved therapy, significant impact on mortality and morbidity, and the psychological and economic burden it puts on the patient, family and society, rheumatoid arthritis has a major public health significance. Although its importance is still underestimated both by the public and the medical community, today an improving tendency can be observed. The past decade has seen important breakthroughs in terms of increased recognition of the significance of the disease, as well as in its pathogenesis, diagnosis and therapy. The introduction of new diagnostic and prognostic markers and early aggressive treatment, the establishment of early arthritis clinics, and, most importantly, the successful use of biological therapy have revolutionized the management of rheumatoid arthritis. The paper reviews the modern therapy of the disease, touching on the options available in Hungary.]

Clinical Neuroscience

[Comparison of subthalamic nucleus planning coordinates in 1Tesla and 3Tesla MRI for deep brain stimulation targeting ]

JUHÁSZ Annamária, KOVÁCS Norbert, PERLAKI Gábor, BÜKI András, KOMOLY Sámuel, KÖVÉR Ferenc, BALÁS István

[Backgroud - Deep brain stimulation (DBS) involves placing electrodes within specific deep brain nuclei. For movement disorders the most common indications are tremors, Parkinsons disease and dystonias. Surgeons mostly employ MR imaging for preoperative target selection. MR field geometrical distortion may contribute to target-selection error in the MR scan which can contribute to error in electrode placement. Methods - In this paper we compared the STN target planning coordinates in six parkinsonian DBS patients. Each patient underwent target planning in 1T and 3T MRI. We statistically compared and analysed the target-, and the fiducial coordinates in two different magnetic fileds. Results - The target coordinates showed no significant differences (Mann-Whitney test, p > 0.05), however we found significant difference in fiducial coordinates (p < 0.01), in 3T MRI it was more pronounced (mean ± SD: 0.8 ± 0.3 mm) comparing to 1T (mean ± SD: 0.4 ± 0.2 mm). Conclusion - Preliminary results showed no significant differences in planning of target coordinates comparing 1T to 3T magnetic fields.]

Clinical Neuroscience

[Positron emission tomography in presurgical localization of epileptic foci]

JUHÁSZ Csaba

[The success of cortical resection for intractable epilepsy of neocortical origin is highly dependent on the accurate presurgical delineation of the regions responsible for generating seizures. In addition to EEG and structural imaging studies, functional neuroimaging such as positron emission tomography (PET) can assist lateralization and localization of epileptogenic cortical areas. In the presented studies, objectively delineated focal PET abnormalities have been analyzed in patients (mostly children) with intractable epilepsy, using two different tracers: 2-deoxy-2-[18F]fluoro-D-glucose (FDG), that measures regional brain glucose metabolism, and [11C]flumazenil (FMZ), that binds to GABAA receptors. The PET abnormalities were correlated with scalp and intracranial EEG findings, structural brain abnormalities, as well as surgical outcome data. In patients with extratemporal foci and no lesion on MRI, FMZ PET was more sensitive than FDG PET for identification of the seizure onset zone defined by intracranial EEG monitoring. In contrast, seizures commonly originated from the border of hypometabolic cortex detected by FDG PET suggesting that such areas are most likely epileptogenic, and should be addressed if subdural EEG is applied to delineate epileptic cortex. In patients with cortical lesions, perilesional cortex with decreased FMZ binding was significantly smaller than corresponding areas of glucose hypometabolism, and correlated well with spiking cortex. Extent of perilesional hypometabolism, on the other hand, showed a correlation with the life-time number of seizures suggesting a seizurerelated progression of brain dysfunction. FMZ PET proved to be also very sensitive for detection of dual pathology (coexistence of an epileptogenic cortical lesion and hippocampal sclerosis). This has a major clinical importance since resection of both the cortical lesion and the atrophic hippocampus is required to achieve optimal surgical results. Finally, the author demonstrated that in patients with neocortical epilepsy, FDG PET abnormalities correctly regionalize the epileptogenic area, but their size is not related to the extent of epileptogenic tissue to be removed. In contrast, complete resection of cortex with decreased FMZ binding predicts good surgical outcome suggesting that application of FMZ PET can improve surgical results in selected patients with intractable epilepsy of neocortical origin.]

Clinical Neuroscience

[P-wave dispersion doesn’t increase in patients with epilepsy]

SENOL Güney Mehmet, ÖZMEN Namik, YASAR Halit, TEKELI Hakan, ÖZDAG Fatih, SARACOGLU Mehmet

[Aim - Epileptic seizures have occasionally been associated with cardiac conditions as atrioventricular blocks, long QT syndrome etc. P-wave dispersion (PWD), which is the difference between the longest (P max) and shortest P-wave duration (P min), is considered as a forerunner of atrial fibrillation. In this study, we investigated P-wave dispersion (PWD) in epileptic patients; based on the hypothesis that microthromboembolism may occur in atrial fibrillation. Methods - Seventy five patients with mixed types of epilepsy and 50 age and sex matched healthy individuals were included into the study. P max, P min and PWD values were calculated for each subject from an ECG. Results - The mean age of subjects in the epilepsy group and control group were similar (p>0.05). P max in patients with epilepsy was 125.1±0.7 ms, P min was 67.3±10.3 ms, and PWD was 57.6±8.3 ms while these values in the control group were 116.8±11.0 ms, 66.5±5.5 ms and 46.8±7.1 ms, respectively. There were no statistically significant difference between two groups (p>0.05). Conclusions - PWD does not increase in patients with mixed types of epilepsy. Therefore we believe that microthromboembolism duo to atrial fibrillation can’t cause epileptic seizures in patients with no structural heart disease.]