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Vasopressin System (vasopressin + system)

Distribution by Scientific Domains

Life Sciences	75%

Selected Abstracts

Further genetic evidence implicates the vasopressin system in childhood-onset mood disorders

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2009
Emma L. Dempster
Abstract Studies in both animals and humans advocate a role for the vasopressin (AVP) system in the aetiology of depressive symptoms. Attention has particularly focused on the role of AVP in the overactivation of the hypothalamic-pituitary-adrenal (HPA)-axis in mood disorders. Elevated AVP plasma levels have been found in mood disorder patients, which are often positively correlated with the severity of symptoms. We recently reported an association between childhood-onset mood disorders (COMD) and polymorphisms in the receptor responsible for the AVP-mediated activation of the HPA-axis (AVPR1B). As genetic variation in the vasopressinergic system could provide a mechanism to explain the endocrine alterations observed in mood disorders, we investigated other genes in this system. The gene encoding AVP is the strongest candidate, particularly as genetic variation in this gene in rodents is associated with anxiety-related behaviours. Six single-nucleotide polymorphisms (SNPs) were genotyped across the AVP gene in a sample comprised of 586 Hungarian nuclear families ascertained through affected probands with a diagnosis of COMD. In addition, AVP coding and putative regulatory regions were screened for mutations using denaturing high-performance liquid chromatography. One SNP, 3, to the AVP, gene reached significance (P = 0.03), as did the overtransmission of a five-marker haplotype with a frequency of 22% (P = 0.0001). The subsequent mutation screen failed to identify any putative functional polymorphisms. The outcome of this study, combined with our previous association between COMD and AVPR1B, implicates genetic variation in vasopressinergic genes in mediating vulnerability to COMD. [source]

Adolescent stress and neural plasticity in hamsters: a vasopressin-serotonin model of inappropriate aggressive behaviour

EXPERIMENTAL PHYSIOLOGY, Issue 2000
Craig F. Ferris
Animal studies show that arginine vasopressin facilitates aggression, while serotonin (5-HT) inhibits aggression by blocking the activity of the vasopressin system. Clinical studies report that subjects with a history of ,fighting and assault' show a significant positive correlation between cerebrospinal fluid concentrations of vasopressin and aggression in the presence of a hyporeactive 5-HT system. Thus, in animals and humans, a hyporeactive 5-HT system may result in enhanced vasopressin activity and increased aggression. Can the stress of emotional and physical insult, i.e. threat and attack, during adolescence affect the development of the vasopressin and 5-HT systems and alter normal aggressive behaviour in early adulthood? Adolescent male golden hamsters were weaned at postnatal day 25, and stressed for 2 weeks by daily 1 h bouts of threat and attack by adult hamsters. Male littermates were run in a parallel stress study using daily 1 h trials of isolation in a novel environment. During early adulthood, on postnatal day 45, 3 days after the cessation of stress trials, animals were tested for aggression in a resident: intruder model. The results show a context-dependent change in aggression. Animals with a history of abuse show exaggerated attack behaviour toward smaller males compared to littermates with a history of isolation stress. Conversely, when confronted by males of equal size, animals with a history of abuse show diminished aggression and increased submission compared to controls. It was determined that the density of vasopressin fibres and neurones in the hypothalamus is lower in abused animals compared to controls. In contrast, the number of 5-HT terminals within the hypothalamus is higher in abused animals compared to controls. These results provide evidence in an animal model that stress in the form of threat and attack during adolescence can alter the balance between vasopressin and 5-HT in the brain, resulting in inappropriate aggressive behaviour in early adulthood. [source]

Veni, vidi, vici: the neurohypophysis in the twentieth century

EXPERIMENTAL PHYSIOLOGY, Issue 2000
John A. Russell
We outline the key discoveries in the first 70 years of research on the neurohypophysis that provided the foundations for more recent studies in the last 30 years. We consider the extent to which these recent studies, which have exploited molecular technologies, cellular electrophysiological techniques and mechanistic behavioural investigations, have advanced or changed our understanding of the functions of oxytocin and vasopressin. The different evolutionary pressures on the oxytocin and vasopressin systems are discussed. Lastly, we focus on the mechanisms underlying the burst-firing activity of oxytocin neurones in lactation as a problem not yet solved, and probably requiring a presently improbable conceptual leap to understand. [source]

Morphological Substrate of the Catecholaminergic Input of the Vasopressin Neuronal System in Humans

JOURNAL OF NEUROENDOCRINOLOGY, Issue 12 2006
B. Dudás
It has been postulated that the stress response is associated with water balance via regulating vasopressin release. Nausea, surgical stress and insulin-induced hypoglycaemia were shown to stimulate vasopressin secretion in humans. Increased vasopressin release in turn induces water resorption through the kidneys. Although the mechanism of the stress-mediated vasopressin release is not entirely understood, it is generally accepted that catecholamines play a crucial role in influencing water balance by modulating the secretion of vasopressin. However, the morphological substrate of this modulation has not yet been established. The present study utilised double-label immunohistochemistry to reveal putative juxtapositions between tyrosine hydroxylase (TH)-immunoreactive (IR) catecholaminergic system and the vasopressin systems in the human hypothalamus. In the paraventricular and supraoptic nuclei, numerous vasopressin-IR neurones received TH-IR axon varicosities. Analysis of these juxtapositions with high magnification combined with oil immersion did not reveal any gaps between the contacted elements. In conclusion, the intimate associations between the TH-IR and vasopressin-IR elements may be functional synapses and may represent the morphological basis of vasopressin release modulated by stressors. Because certain vasopressin-IR perikarya receive no detectable TH innervations, it is possible that additional mechanisms may participate in the stress-influenced vasopressin release. [source]