Clinical Neuroscience

[THE ROLE OF VASOPRESSIN IN CHRONIC STRESS STUDIED IN A CHRONIC MILD STRESS MODEL OF DEPRESSION]

ZELENA Dóra1, DOMOKOS Ágnes1, BARNA István1, CSABAI Katalin1, BAGDY György2, MAKARA B. Gábor1

MARCH 20, 2007

Clinical Neuroscience - 2007;60(03-04)

[Background and purpose - Vasopressin plays an important role in the hypothalamo-pituitary-adrenal axis regulation as well as in stress-related disorders. A common view suggested that the role of vasopressin is especially important during chronic stresses. Here we tested the hypothesis that vasopressin-deficient rats may be more resistant to the development of chronic hypothalamo-pituitary-adrenal axis hyperactivity after chronic mild stress. Methods - Male vasopressin deficient Brattleboro rats were compared to their heterozygous littermattes. Chronic mild stress consisted of different mild stimuli (e.g. wet cages, restraint) for 6 week. The corticosterone changes were followed by repeated tail cutting and organs and blood were collected from decapitated rats. Results - In controls, chronic mild stress resulted in symptoms of chronic stress state characterized by typical somatic (body weight reduction, thymus involution) and endocrine changes (resting plasma ACTH and corticosterone elevation and POMC mRNA elevation in anterior lobe of the pituitary). Unexpectedly, the lack of vasopressin could not influence any chronic mild stress-induced changes. Conclusion - Somatic changes and endocrine effects of chronic mild stress are similar in control and vasopressin deficient animals. This suggests that either vasopressin is not indispensable for activating the hypothalamo-pituitaryadrenal axis by chronic stress or the absence of vasopressin is compensated by other mediators (e.g. CRH) in Brattleboro rats.]

AFFILIATIONS

  1. Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest
  2. National Institute of Psychiatry and Neurology, Budapest

COMMENTS

0 comments

Further articles in this publication

Clinical Neuroscience

[HUMAN TRYPSIN(OGEN) 4-LIKE IMMUNOREACTIVITY IN THE WHITE MATTER OF THE CEREBRAL CORTEX AND THE SPINAL CORD]

GALLATZ Katalin, MEDVECZKY Péter, NÉMETH Péter, SZILÁGYI László, GRÁF László, PALKOVITS Miklós

[Human brain trypsin(ogen) 4-like (HT-4) immunoreactivity was localized in glial cells of human cerebral cortex and spinal cord. After a short post mortem delay (two hours), cortical and spinal cord regions were dissected, frozen or immersed into a fixative solution. Sections of 10 and 50 µm thickness were cut and immunostained by antibodies raised against recombinant human trypsin 4. HT-4-like immunoreactive glial cells and fibers were stained in the white matter, low to moderate levels of immunostaining were also observed in the matrix of the cerebral cortex and the spinal cord. To characterize HT-4-like immunopositive glial cells, alternate sections were immunostained for astrocytes and oligodendrocytes. HT-4 is present predominantly in astrocytes, but some of the oligodendrocytes and microglial cells may also contain this enzyme.]

Clinical Neuroscience

[HISTOCHEMISTRY OF THE EXTRACELLULAR MATRIX IN THE SNAIL CENTRAL NERVOUS SYSTEM]

SERFŐZŐ Zoltán, ELEKES Károly

[Even tough the central nervous system (CNS) of gastropods has long been used as a model for studying different neuronal networks underlying behaviors, there is only little information on the molecular components of the extracellular matrix (ECM) of the nervous tissue. Therefore, the aim of the present study was to identify some of the ECM molecules by acid-base histochemistry. Staining with alcian blue at strong acidic pH, and with acridine orange at different pH and salt concentrations was carried out on cryostat sections taken from CNS preparations of adult specimens of the terrestrial snail, Helix pomatia, and the aquatic species, Lymnaea stagnalis, in order to visualize mild (carboxyl) and strong (sulphate) acidic groups, which are characteristic for different glucosaminoglycans. According to our findings, sulphated proteoglycans were abundant in the periganglionic sheath of both species, and they also occurred in the neuropil of Helix, whereas they were absent in Lymnaea. The interperikaryonal space contained mainly carboxyl residues, which might refer to the presence of hyaluronic acid. It is concluded that the ECM of the snail CNS, similarly to that in vertebrates, is partly composed of polymer macromolecules of different chemical properties. It is suggested that adaptation to environmental conditions and/or altered neuronal plasticity are responsible for the differences found in chemical characters of the ECM molecules between the two snail species.]

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

[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

[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.]

All articles in the issue

Related contents

Clinical Neuroscience

[The transcription of the amyloid precursor protein and tryptophan 2,3-dioxygenase genes are increased by aging in the rat brain]

KÁLMÁN Sára, PÁKÁSKI Magdolna, SZŰCS Szabina, GARAB Dénes, DOMOKOS Ágnes, ZVARA Ágnes, PUSKÁS László, BAGDY György, ZELENA Dóra, KÁLMÁN János

[Aging itself is considered as a major risk factor of dementia. The prevalence of the Alzheimer’s disease (AD) is increasing exponentially after the age of 65 and doubles every 5 years. The major aim of our present research was to examine the effect of aging on the transcription of certain genes associated with neurodegenerative disorders in the rat brain. The influence of the vasopressin (VP) hormone was also examined in the same experimental paradigm. Age dependent transcriptional changes of the following four genes were examined in the cerebral cortex: the first was the gene of the amyloid precursor protein (APP) which is abnormally cleaved to toxic beta-amyloid fragments. These aggregated peptides are the major components of the senile plaques in the AD brain. The second one was the mitogen-activated protein kinase (MAPK1) gene. The MAPK is involved in the abnormal hyperphosphorylation of the tau-protein which results in aggregated neurofibrillary tangles. The beta-actin gene was the third one. The protein product of this gene is considered to be involved in synaptogenesis, neuronal plasticity and clinical conditions like depression and AD. The last one was the gene of the tryptophan 2,3-dioxygenase (TDO2) enzyme. The activity of this enzyme is considered as a rate limiting factor in the metabolism of the neuro-immune modulator quinolinic acid (QUIN). The transciptional activity of young (2.5 months) and aged (13 months) Brattleboro rats with or without VP expression were compared by means of real time PCR technique. The cortical transciptional activity of the APP and TDO2 genes were increased in the aged animals as compared with the activity of the young ones, and this effect was independent on the presence of the VP. Our results indicate the importance of certain age dependent transcriptional changes might influence the mechanism of AD and other neurodegenerative disorders.]

Lege Artis Medicinae

[Psychoendocrine aspects of chronic stress, depression and eating disorders]

MOLNÁR Ildikó, MOLNÁR Gábor

[The brain is not only a central organ, but also a target of stress-related events. During chronic stress, many somatic and psychiatric disorders could be initiated by the decreased allostatic or adaptive abilities of the individual. The brain is involved in the regulation of stress-related events via hormones, neuropeptides, monoamines and cytokines. A number of endocrine diseases or hormonal changes are associated with behavioural, vegetative and emotional alterations, which occasionally lead to psychological disturbances, for example depression. The endocrine background is also reflected by the medical treatment of psychiatric patients, as demonstrated by the use of selective serotonin-reuptake inhibitors, and estrogen or levothyroxine substitution therapies. The psychiatric disorders presented here, such as the various forms of depression and eating disorders (anorexia and bulimia nervosa) are highlighted because of their frequencies and lifethreatening nature. By describing these disorders, we wish to aid their early diagnosis and treatment and to help incorporate them into everyday clinical practice.]

Clinical Neuroscience

[Regulation of water transport in brain oedema]

DÓCZI Tamás, SCHWARCZ Attila, GALLYAS Ferenc, BOGNER Péter, PÁL József, SULYOK Endre, GÖMÖRI Éva, VAJDA Zsolt

[The study gives an overview on the regulation of cerebral water content and of brain volume. The molecular mechanisms of the development and resolution of various oedema forms are discussed in detail. The physiological and pathophysiological role of the recently discovered molecular water channel proteins aquaporin-1 (AQP1) and aquaporin-4 (AQP4) as well as the importance of central neuroendocrine regulation by vasopressin and atriopeptin are reviewed based on the relevant literature and personal studies. Quantitative water maps based on the combination of multicompartment- T2, diffusion weighted MRI and T1 studies have proven to be powerful tools for studying new drugs against brain oedema brought about by various neuropathological conditions and for testing their efficacy both in animal experimental and clinical conditions. Non-peptide vasopressin antagonists, atriopeptin agonists and drugs targeting AQP4 are potential new families of oedema-decreasing drugs.]

Clinical Neuroscience

[PERSONAL RECOLLECTIONS OF DR. HANS SELYE AND OF HIS INSTITUT DE MÈDECINE ET DE CHIRURGIE EXPÈRIMENTALES (IMCE)]

MILAGROS Salas-Prato

[This article is a short personal recollection of Dr. Hans Selye (HS) and of his institute in order to show, first, why and how he influenced us; second, who he was as a person, human being, physician, scientist, professor, mentor; third, what was the structure and functioning of the Institut de mèdecine et chirurgie expèrimentales (IMCE) and fourth, what HS’ contributions and accomplishments were.]