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Chronic Dehydration (chronic + dehydration)
Selected AbstractsImpact of Sim1 gene dosage on the development of the paraventricular and supraoptic nuclei of the hypothalamusEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2009Sabine Michaëlle Duplan Abstract The bHLH-PAS transcription SIM1 is required for the development of all neurons of the paraventricular nucleus (PVN) and supraoptic nucleus (SON) of the hypothalamus. Mice with a loss of Sim1 die within a few days of birth, presumably because of the lack of a PVN and SON. In contrast, mice with a decrease of Sim1 survive, are hyperphagic and become obese. The mechanism by which Sim1 controls food intake remains unclear. Here we show that the development of specific PVN and SON cell types is sensitive to Sim1 gene dosage. Sim1 haploinsufficiency reduces the number of vasopressin (AVP)- and oxytocin-producing cells in the PVN by about 50 and 80%, respectively, but does not affect the development of Crh, Trh and Ss neurons. A decrease of AVP-producing cells increases the sensitivity of Sim1 heterozygous mice to chronic dehydration. Moreover, retrograde labelling showed a 70% reduction of PVN neurons projecting to the dorsal vagal complex, raising the possibility that a decrease of these axons contributes to the hyperphagia of Sim1+/, mice. Sim1 haploinsufficiency is thus associated with a decrease of several PVN/SON cell types, which has the potential of affecting distinct homeostatic processes. [source] Functional Consequences of Morphological Neuroglial Changes in the Magnocellular Nuclei of the HypothalamusJOURNAL OF NEUROENDOCRINOLOGY, Issue 3 2002S. H. R. OlietArticle first published online: 8 APR 200 Abstract The supraoptic and paraventricular nuclei of the hypothalamus undergo reversible anatomical changes under conditions of intense neurohypophysial hormone secretion, such as lactation, parturition and chronic dehydration. This morphological remodelling includes a reduction in astrocytic coverage of neurones resulting in an increase in the number and extent of directly juxtaposed somatic and dendritic surfaces. There is a growing body of evidence indicating that such anatomical plasticity is of functional significance. Astrocytic-dependent clearance of electrolytes and neurotransmitters from the extracellular space appears to be altered under conditions where glial coverage of magnocellular neurones is reduced. Glutamate, for example, has been found to accumulate in the extracellular space in the supraoptic nucleus of lactating animals and cause a modulation of synaptic efficacy. On the other hand, the range of action of substances released from astrocytes and acting on adjacent magnocellular neurones is expected to be limited during such anatomical remodelling. It thus appears that the structural plasticity of the magnocellular nuclei does affect neuroglial interactions, inducing significant changes in signal transmission and processing. [source] Serum markers of chronic dehydration are associated with saliva spinabilityJOURNAL OF ORAL REHABILITATION, Issue 10 2007A. YOSHIHARA Summary, Findings of a relationship between saliva and dehydration have been observed, but the precise nature of these relationships is unclear and no evidence of a direct link has been found. In particular, no study reports a relationship between chronic dehydration and saliva conditions in community-dwelling older adults. This study aimed to identify whether salivary conditions are sensitive to body hydration markers in an elderly population. A total of 403 subjects aged 76 years participated in the study. Stimulated saliva flow rate and spinability of saliva were measured. In addition, determinations of serum levels of uric acid, blood urea nitrogen (BUN), creatinine, sodium and potassium were made. Dehydration was defined as uric acid , 7 mg dL,1 according to the standard value. The salivary spinability were significantly associated with the concentration of uric acid (OR=2·06, P=0·044) according to multiple logistic regression analysis. In addition, after adjusting for gender, the uric acid concentration and the salivary spinability was significantly associated with BUN, potassium and creatinine levels. The subjects with high uric acid levels (,,7 mg dL,1) had the most elastic saliva. Both BUN and serum creatinine are the most commonly used indicators of renal function. Therefore, our findings might demonstrate that older adults who are dehydrated showed highly elastic saliva, which was associated with renal function. In conclusion, this study suggests that there is a significant relationship between chronic dehydration status and salivary spinability level. [source] | ||||||||||