Responses from osmosensitive neurons of the rat subfornical organ in vitro

Sibbald, John R.; Hubbard, J. I.; Sirett, Nancy E.

doi:10.1016/0006-8993(88)90251-x

Cited by 87 publications

(27 citation statements)

References 13 publications

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“…This could be the case of CaSR expression in the white matter for oligodendroglial cells or in the cerebral cortex and in the striatum for neurons. By contrast, some brain nuclei showed very high levels of CaSR mRNA suggesting a role of CaSR in region-specific neuronal functions, such as in the subfornical organ for the regulation of ionic calcium levels in the blood (Sibbald et al, 1988) or in the area postrema for autonomic control of several physiological systems, including the cardiovascular system and the systems controlling feeding and metabolism (Fry and Ferguson, 2007). However, the CaSR present in neuronal cells could potentially contribute to the control of Ca 2 + levels, which in turn are involved in a variety of neuronal functions, such as signal transduction, generation and propagation of action potentials, and neurotransmitter release.…”

Section: Discussionmentioning

confidence: 90%

Identification of calcium sensing receptor (CaSR) mRNA-expressing cells in normal and injured rat brain

et al. 2009

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Calcium sensing receptor (CaSR), isolated for the first time from bovine and human parathyroid, is a G-protein-coupled receptors that has been involved in diverse physiological functions. At present a complete in vivo work on the identification of CaSR mRNA-expressing cells in the adult brain lacks and this investigation was undertaken in order to acquire more information on cell type expressing CaSR mRNA in the rat brain and to analyse for the first time its expression in different experimental models of brain injury.The expression of CaSR mRNAs was found mainly in scattered cells throughout almost all the brain regions. A double labeling analysis showed a colocalization of CaSR mRNA expression in neurons and oligodendrocytes, whereas it was not found expressed both in the microglia and in astrocytes. One week after kainate-induced seizure CaSR was found in the injured CA3 region of the hippocampus and very interestingly it was found upregulated in the neurons of CA1-CA2 and dentate gyrus. Similarly, 1 week following ibotenic acid injection in the hippocampus, CaSR mRNA expression was increased in oligodendrocytes both in the lesioned area and in the contralateral CA1-CA3 pyramidal cell layers and dentate gyrus. One week after needle-induced mechanical lesion an increase of labeled cells expressing CaSR mRNA was observed along the needle track. In conclusion, the present results contribute to extend available data on cell type-expressing CaSR in normal and injured brain and could spur to understand the role of CaSR in repairing processes of brain injury.

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Section: Discussionmentioning

confidence: 90%

Identification of calcium sensing receptor (CaSR) mRNA-expressing cells in normal and injured rat brain

et al. 2009

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“…*P Ͻ 0.05 vs. isotonic NaCl; #P Ͻ 0.05 vs. hyperosmotic NaCl. (3,4,21,23,34,45), SON and PVN receive input from osmoreceptors in CVOs (18,28,33,40), and a disconnection of one CVO, the SFO, greatly reduces Fos expression in the SON and PVN after hyperosmotic intragastric loads (11,38). Thus, cells in the hypothalamus are activated both by native osmoreceptors and by afferents from the CVOs after hyperosmotic NaCl infusion.…”

Section: Discussionmentioning

confidence: 99%

“…The data provide strong support for the conclusion that the osmoreceptors controlling drinking are located in the CVOs. area postrema; c-Fos; drinking; hypernatremia; organum vasculosum laminae terminalis; osmoreceptors; paraventricular nucleus of the hypothalamus; subfornical organ; supraoptic nucleus THE BRAIN AREAS THAT CONTAIN electrophysiologically defined osmoreceptive cells that function in the regulation of fluid and electrolyte balance include the circumventricular organs (CVOs), the median preoptic nucleus (MnPO), the hypothalamic supraoptic and paraventricular nuclei (SON and PVN), and the nucleus of the solitary tract (1,17,18,33,34,40,43). These areas are intricately interconnected by neural pathways into a network subserving fluid balance as originally described by Miselis (29).…”

mentioning

confidence: 99%

Differential effects of intravenous hyperosmotic solutes on drinking latency and c-Fos expression in the circumventricular organs and hypothalamus of the rat

Ho¹,

Zierath²,

Savos³

et al. 2007

American Journal of Physiology-Regulatory, Integrative and Comp

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December 28, 2006; doi:10.1152/ajpregu.00547.2006.-Hyperosmotic intravenous infusions of NaCl are more potent for inducing drinking and vasopressin (AVP) secretion than equally osmotic solutions of glucose or urea. The fact that all three solutes increased cerebrospinal fluid osmolality and sodium concentration led the investigators to conclude that critical sodium receptors or osmoreceptors for stimulating drinking and AVP secretion were outside the blood-brain barrier (BBB) in the circumventricular organs (CVOs). We tested an obvious prediction of this hypothesis: that all three solutes should increase c-Fos-like immunoreactivity (Fos-ir) inside the BBB, but that only NaCl should increase Fos-ir in the CVOs. We gave intravenous infusions of 3.0 Osm/l NaCl, glucose, or urea to rats for 11 or 22 min at 0.14 ml/min and perfused the rats for assay of Fos-ir at 90 min. Controls received isotonic NaCl at the same volume. Drinking latency was measured, but water was then removed. Drinking consistently occurred with short latency during hyperosmotic NaCl infusions only. Fos-ir in the forebrain CVOs, the subfornical organ, and organum vasculosum laminae terminalis was consistently elevated only by hyperosmotic NaCl. However, all three hyperosmotic solutes potently stimulated Fos-ir in the supraoptic and paraventricular nuclei of the hypothalamus inside the BBB. Hyperosmotic NaCl greatly elevated Fos-ir in the area postrema, but even glucose and urea caused moderate elevations that may be related to volume expansion rather than osmolality. The data provide strong support for the conclusion that the osmoreceptors controlling drinking are located in the CVOs. area postrema; c-Fos; drinking; hypernatremia; organum vasculosum laminae terminalis; osmoreceptors; paraventricular nucleus of the hypothalamus; subfornical organ; supraoptic nucleus THE BRAIN AREAS THAT CONTAIN electrophysiologically defined osmoreceptive cells that function in the regulation of fluid and electrolyte balance include the circumventricular organs (CVOs), the median preoptic nucleus (MnPO), the hypothalamic supraoptic and paraventricular nuclei (SON and PVN), and the nucleus of the solitary tract (1,17,18,33,34,40,43). These areas are intricately interconnected by neural pathways into a network subserving fluid balance as originally described by Miselis (29). Candidate mechanisms for osmoreceptors have been identified among aquaporins, the vanilloid family of transient receptor potential channels, and mechanical gating of sodium currents (3,22,44,45). However, electrophysiological studies in single neurons or brain slices do little to differentiate which osmoreceptors are more important for functions such as AVP secretion or drinking.The concept that the critical osmoreceptors for these functions are located in the CVOs and in the peripheral nervous system stems from three influential studies that demonstrated drinking in sheep, dogs, and rats was elicited by intravenous hyperosmotic NaCl or sucrose but not by urea or glucose (8,26,41). The generally...

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“…A variety of neuronal types are found there, including osmosensitive neurons [44], choliner gic and serotonergic neurons [1,6] and peptidergic fibers [5]. In turn, direct efferent outputs from the subfornical organ to the supraoptic and paraventricular nuclei of the hypothalamus and the medial preoptic nucleus have been reported 112, 28, 33, 38].…”

Section: Lhrh Systems and The Circumventricular Organsmentioning

confidence: 99%

Terminations of LHRH-Immunoreactive Fibers in the Subfornical Organ of the Opossum: an Ultrastructural Study

Zheng

Pfaff²,

Schwanzel‐Fukuda³

1990

Neuroendocrinology

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Electron microscopic immunocytochemical approaches were used to analyze LHRH-containing elements in the subfomical organ of the opossum, a species in which this input to the subfomical organ is prominent. Not only were LHRH synaptic specializations easily demonstrated in the subfomical organ, forming axo-dendritic and axo-axonal contacts, but also LHRH-immunoreactive fibers contacted astrocytic end-feet on fenestrated capillaries and were found in the subependymal layer. LHRH-carrying elements in the subfomical organ may be important for relating reproductive functions to body fluid balance.

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Responses from osmosensitive neurons of the rat subfornical organ in vitro

Cited by 87 publications

References 13 publications

Identification of calcium sensing receptor (CaSR) mRNA-expressing cells in normal and injured rat brain

Identification of calcium sensing receptor (CaSR) mRNA-expressing cells in normal and injured rat brain

Differential effects of intravenous hyperosmotic solutes on drinking latency and c-Fos expression in the circumventricular organs and hypothalamus of the rat

Terminations of LHRH-Immunoreactive Fibers in the Subfornical Organ of the Opossum: an Ultrastructural Study

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