Time Course of c-fos, vasopressin and oxytocin mRNA Expression in the Hypothalamus Following Long-Term Dehydration

Silveira, Lenise Trito Garcia da; Junta, Cristina M.; Monesi, Nádia; Oliveira-Pelegrin, Gabriela Ravanelli; Passos, Geraldo A. S.; Rocha, Maria José Alves da

doi:10.1007/s10571-007-9144-2

Cited by 21 publications

(18 citation statements)

References 44 publications

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“…Both WD and SL animals consumed significantly less food and weighed less compared with their EU state, a finding in line with previous studies (12,21,49), but the magnitude of the drop was the largest in the WD group where eating was quickly attenuated. Animals undergoing WD quickly lose their appetite, presumably because the salt in food will exacerbate the problem of rising ECF sodium and because water is required for salivation and digestion.…”

Section: R565 Osmotic Stimulation Of the Sonsupporting

confidence: 90%

“…In the SON, WD induces a large elevation of AVP and OXT that is commensurate with cFos expression. In contrast, in the PVN, the AVP and OXT expression change in response to WD is not as steep as for cFos and peaks at a different time point (12). Because the PVN is out of the scope of this paper, we cannot at this point comment on the role of the PVN in the maintenance of circulating OXT peptide levels and therefore we can only speculate on the role of this structure in the mediation of sustained peptide release from the pituitary and subsequent circulating levels.…”

Section: R565 Osmotic Stimulation Of the Sonmentioning

confidence: 74%

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A comparison of physiological and transcriptome responses to water deprivation and salt loading in the rat supraoptic nucleus

Greenwood

Mecawi

Hoe

et al. 2015

American Journal of Physiology-Regulatory, Integrative and Comp

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-Salt loading (SL) and water deprivation (WD) are experimental challenges that are often used to study the osmotic circuitry of the brain. Central to this circuit is the supraoptic nucleus (SON) of the hypothalamus, which is responsible for the biosynthesis of the hormones, arginine vasopressin (AVP) and oxytocin (OXT), and their transport to terminals that reside in the posterior lobe of the pituitary. On osmotic challenge evoked by a change in blood volume or osmolality, the SON undergoes a functionrelated plasticity that creates an environment that allows for an appropriate hormone response. Here, we have described the impact of SL and WD compared with euhydrated (EU) controls in terms of drinking and eating behavior, body weight, and recorded physiological data including circulating hormone data and plasma and urine osmolality. We have also used microarrays to profile the transcriptome of the SON following SL and remined data from the SON that describes the transcriptome response to WD. From a list of 2,783 commonly regulated transcripts, we selected 20 genes for validation by qPCR. All of the 9 genes that have already been described as expressed or regulated in the SON by osmotic stimuli were confirmed in our models. Of the 11 novel genes, 5 were successfully validated while 6 were false discoveries. transcriptome; supraoptic nucleus; water restriction; salt load; neuroendocrine TERRESTRIAL LIFE requires that the osmolality of the extracellular fluid (ECF) is strictly controlled. Increased ECF osmolality results in water leaving the cell, reducing intracellular fluid (ICF) volume, while increasing ICF osmolality, which will compromise the metabolic processes necessary for life. Chronic increases in ECF osmolality can be brought about experimentally by a high intake of salt (salt loading, SL) or by water deprivation (WD) (5). In the absence of drinking fluid (WD), extracellular and intracellular fluid volumes decrease, as water and sodium are inevitably lost in sweat and urine leading to hypovolemia and, as a consequence of dehydration-induced natriuresis, sodium depletion (14,35). This depletion of sodium means that WD animals also display enhanced salt appetite (14). In contrast, SL increases body sodium content, causing an increase in ECF volume, but a decrease in the volume of the ICF (35).Angiotensin II (ANG II), atrial natriuretic peptide (ANP), arginine vasopressin (AVP), and oxytocin (OXT) are the main hormones involved in the control of hydromineral homeostasis in mammals (5). ANP is synthesized and secreted into the bloodstream in response to stretching of the right atrial muscle cells by increased blood volume. Once in the bloodstream, ANP has a potent natriuretic effect, acting on the distal convoluted tubule of the nephron to inhibit sodium reabsorption (13,44). ANP is an important indicator of blood volume. AVP and OXT release are stimulated by hypovolemia, hypertonicity, and hypernatremia, among other stimuli (36). Circulating levels of AVP correlate with plasma osmolality (4) and thirst perce...

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Section: R565 Osmotic Stimulation Of the Sonsupporting

confidence: 90%

Section: R565 Osmotic Stimulation Of the Sonmentioning

confidence: 74%

A comparison of physiological and transcriptome responses to water deprivation and salt loading in the rat supraoptic nucleus

Greenwood

Mecawi

Hoe

et al. 2015

American Journal of Physiology-Regulatory, Integrative and Comp

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“…Prolonged salt loading and water deprivation, in a time-dependent manner, significantly increase OXY mRNA levels (da Silveira et al 2007), but decrease OXY peptide levels in the PVN, SON (Meister et al 1990b), and posterior pituitary and elevate its level in the plasma (Balment et al 1980). This strongly indicates that increase in the turn-over of OXY in the hypothalamus and OXY levels in plasma is in positive correlation with increased osmolality status (Verbalis and Dohanics 1991).…”

Section: Son and Pvn Principal Osmoregulatory Neuropeptidesmentioning

confidence: 97%

Response of Substances Co-Expressed in Hypothalamic Magnocellular Neurons to Osmotic Challenges in Normal and Brattleboro Rats

et al. 2008

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The intention of this review is to emphasize the current knowledge about the extent and importance of the substances co-localized with magnocellular arginine vasopressin (AVP) and oxytocin (OXY) as potential candidates for the gradual clarification of their actual role in the regulation of hydromineral homeostasis. Maintenance of the body hydromineral balance depends on the coordinated action of principal biologically active compounds, AVP and OXY, synthesized in the hypothalamic supraoptic and paraventricular nuclei. However, on the regulation of water-salt balance, other substances, co-localized with the principal neuropetides, participate. These can be classified as (1) peptides co-localized with AVP or OXY with unambiguous osmotic function, including angiotensin II, apelin, corticotropin releasing hormone, and galanin and (2) peptides co-localized with AVP or OXY with an unknown role in osmotic regulation, including cholecystokinin, chromogranin/secretogranin, dynorphin, endothelin-1, enkephalin, ferritin protein, interleukin 6, kininogen, neurokinin B, neuropeptide Y, vasoactive intestinal peptide, pituitary adenylate cyclase-activating polypeptide, TAFA5 protein, thyrotropin releasing hormone, tyrosine hydroxylase, and urocortin. In this brief review, also the responses of these substances to different hyperosmotic and hypoosmotic challenges are pointed out. Based on the literature data published recently, the functional implication of the majority of co-localized substances is still better understood in non-osmotic than osmotic functional circuits. Brattleboro strain of rats that does not express functional vasopressin was also included in this review. These animals suffer from chronic hypernatremia and hyperosmolality, accompanied by sustained increase in OXY mRNA in PVN and SON and OXY levels in plasma. They represent an important model of animals with constantly sustained osmolality, which in the future, will be utilizable for revealing the physiological importance of biologically active substances co-expressed with AVP and OXY, involved in the regulation of plasma osmolality.

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“…The locomotor activity during water deprivation was compared with spontaneous locomotor activity in ad libitum drinking (basal locomotor activity). Water deprivation increases the activity of vasopressin neurons in the supraoptic nucleus (SON) and paraventricular nucleus (PVN) and increases AVP concentration in the CSF (SzczepanskaSadowska et al, 1983;da Silveira et al, 2007). After 36 h of water deprivation, the plasma osmolarity was significantly increased in both wild-type mice and orexin/ataxin-3 mice.…”

Section: Activation Of Orexin Neurons Through V1ar Is Important In Thmentioning

confidence: 99%

Vasopressin Increases Locomotion through a V1a Receptor in Orexin/Hypocretin Neurons: Implications for Water Homeostasis

Tsunematsu¹,

Fu²,

Yamanaka³

et al. 2008

J. Neurosci.

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Water homeostasis is a critical challenge to survival for land mammals. Mice display increased locomotor activity when dehydrated, a behavior that improves the likelihood of locating new sources of water and simultaneously places additional demands on compromised hydration levels. The neurophysiology underlying this well known behavior has not been previously elucidated. We report that the anti-diuretic hormone arginine-vasopressin (AVP) is involved in this response. AVP and oxytocin directly induced depolarization and an inward current in orexin/hypocretin neurons. AVP-induced activation of orexin neurons was inhibited by a V1a receptor (V1aR)-selective antagonist and was not observed in V1aR knock-out mice, suggesting an involvement of V1aR. Subsequently activation of phospholipase C␤ triggers an increase in intracellular calcium by both calcium influx through nonselective cation channels and calcium release from calcium stores in orexin neurons. Intracerebroventricular injection of AVP or water deprivation increased locomotor activity in wild-type mice, but not in transgenic mice lacking orexin neurons. V1aR knock-out mice were less active than wild-type mice. These results suggest that the activation of orexin neurons by AVP or oxytocin has an important role in the regulation of spontaneous locomotor activity in mice. This system appears to play a key role in water deprivation-induced hyperlocomotor activity, a response to dehydration that increases the chance of locating water in nature.

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Time Course of c-fos, vasopressin and oxytocin mRNA Expression in the Hypothalamus Following Long-Term Dehydration

Cited by 21 publications

References 44 publications

A comparison of physiological and transcriptome responses to water deprivation and salt loading in the rat supraoptic nucleus

A comparison of physiological and transcriptome responses to water deprivation and salt loading in the rat supraoptic nucleus

Response of Substances Co-Expressed in Hypothalamic Magnocellular Neurons to Osmotic Challenges in Normal and Brattleboro Rats

Vasopressin Increases Locomotion through a V1a Receptor in Orexin/Hypocretin Neurons: Implications for Water Homeostasis

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