c-&lt;i&gt;fos&lt;/i&gt; Expression in Vasopressin and Oxytocin Neurons Reveals Functional Heterogeneity within Magnocellular Neurons

Roberts, Michelle; Robinson, Alan G.; Fitzsimmons, Mark D.; Grant, Fred; Lee, Wen Sen; Hoffman, Gloria E.

doi:10.1159/000126384

Cited by 87 publications

(32 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…There may be different activating thresholds between the neurons in the PVN and SON in their sensitivity to several factors that vary due to running speed. In fact, SON magnocellular neurons show higher sensitivity to several stimuli (hemorrhage, hypotension) than do mPVN neurons (34,36). Thus it may be that AVP neurons in the mPVN are activated by more intense running.…”

Section: Discussionmentioning

confidence: 98%

Delineation of responsive AVP-containing neurons to running stress in the hypothalamus

Saito¹,

Soya²

2004

American Journal of Physiology-Regulatory, Integrative and Comp

View full text Add to dashboard Cite

Running becomes a stress, termed running stress, if it persists above the lactate threshold (LT) and results in enhanced plasma ACTH level in humans. Although the exact underlying regulation mechanism is still uncertain, hypothalamic AVP has been shown to play a dominant role in running-induced ACTH release. It is still not known, however, whether running stress activates the hypothalamic AVP-containing neurons that are involved in the activation of the ACTH response. For this reason, we applied our rat running stress model, in which both plasma ACTH and osmolality levels increase just above LT running (supra-LT running), to delineate which hypothalamic AVP neurons were responsive to running stress. Rats were previously habituated to running and then subjected to a 30-min run either just below or above the LT. Plasma samples were collected from these animals to determine ACTH and osmolality levels. Brains were prepared for immunocytochemistry for both AVP/Fos in the hypothalamus and enzyme immunoassay for the stalk median eminence (SME) AVP content. Only supra-LT running resulted in an increase in the number of Fos/AVP-immunoreactive neurons in both the parvocellular paraventricular nucleus (pPVN) and the magnocellular supraoptic nucleus (SON) accompanied by increased ACTH and plasma osmolality levels. Similarly, running reduced the SME content of the AVP. We thus found that AVP-containing neurons located in both the pPVN and SON are responsive to running stress just above the LT.

show abstract

Section: Discussionmentioning

confidence: 98%

Delineation of responsive AVP-containing neurons to running stress in the hypothalamus

Saito¹,

Soya²

2004

American Journal of Physiology-Regulatory, Integrative and Comp

View full text Add to dashboard Cite

show abstract

“…c-Fos protein is measured after an acute stimulus, with the protein expression peaking ϳ90 min after the stimulus (23) and has been used to study neuroendocrine function (18,50,53). Unilateral intra-PVN injection of SB-222200 significantly decreased c-Fos expression to HDZ treatment in both VP and OT magnocellular neurons by ϳ70%, indicating a role for NK3R in c-Fos expression.…”

Section: Discussionmentioning

confidence: 99%

Blockade of NK3R signaling in the PVN decreases vasopressin and oxytocin release and c-Fos expression in the magnocellular neurons in response to hypotension

Haley¹,

Flynn²

2008

American Journal of Physiology-Regulatory, Integrative and Comp

View full text Add to dashboard Cite

Tachykinin neurokinin 3 receptor (NK3R) signaling has a broad role in vasopressin (VP) and oxytocin (OT) release. Hydralazine (HDZ)-induced hypotension activates NK3R expressed by magnocellular neurons, increases plasma VP and OT levels, and induces c-Fos expression in VP and OT neurons. Intraventricular pretreatment with the specific NK3R antagonist, SB-222200, eliminates the HDZ-stimulated VP and OT release. NK3R are distributed in the central pathways conveying hypotension information to the magnocellular neurons, and the NK3R antagonist could act anywhere in the pathways. Alternatively, the antagonist could act at the NK3R expressed by the magnocellular neurons. To determine whether blockade of NK3R on magnocellular neurons impairs VP and OT release to HDZ, rats were pretreated with a unilateral PVN injection of 0.15 M NaCl or SB-222200 prior to an intravenous injection of 0.15 M NaCl or HDZ. Blood samples were taken, and brains were processed for VP/c-Fos and OT/c-Fos immunohistochemistry. Intravenous injection of 0.15 M NaCl did not alter plasma hormone levels, and little c-Fos immunoreactivity was present in the PVN. Conversely, intravenous injection of HDZ increased plasma VP and OT levels and c-Fos expression in VP and OT magnocellular neurons. Intra-PVN injection of SB-222200 prior to an intravenous injection of HDZ significantly decreased c-Fos expression in both VP and OT neurons by approximately 70% and attenuated plasma VP and OT levels by 33% and 35%, respectively. Therefore, NK3R signaling in magnocellular neurons has a critical role for the release of VP and OT in response to hypotension.

show abstract

“…The anti-VP-NP (Rob-VP) and the anti-OT-NP (Rob-OT) antiserum used for double labeling with MR antibody were provided by Alan Robinson (UCLA). Rob-VP and -OT antisera (53) were raised in rabbit against VP-NP or OT-NP, respectively, and used at 1:20,000 and 1:10,000 dilutions, respectively.…”

Section: Double Immunolabelingmentioning

confidence: 99%

Epithelial Na⁺ sodium channels in magnocellular cells of the rat supraoptic and paraventricular nuclei

Teruyama

Sakuraba

Wilson

et al. 2012

American Journal of Physiology-Endocrinology and Metabolism

View full text Add to dashboard Cite

Teruyama R, Sakuraba M, Wilson LL, Wandrey NE, Armstrong WE. Epithelial Na ϩ sodium channels in magnocellular cells of the rat supraoptic and paraventricular nuclei. Am J Physiol Endocrinol Metab 302: E273-E285, 2012. First published November 1, 2011; doi:10.1152/ajpendo.00407.2011.-The epithelial Na ϩ channels (ENaCs) are present in kidney and contribute to Na ϩ and water homeostasis. All three ENaC subunits (␣, ␤, and ␥) were demonstrated in the cardiovascular regulatory centers of the rat brain, including the magnocellular neurons (MNCs) in the supraoptic nucleus (SON) and the paraventricular nucleus (PVN). However, the functional significance of ENaCs in vasopressin (VP) and oxytocin (OT) synthesizing MNCs is completely unknown. In this study, we show with immunocytochemical double-labeling that the ␣-ENaC is colocalized with either VP or OT in MNCs in the SON and PVN. In addition, parvocellular neurons in the dorsal, ventrolateral, and posterior subregions of the PVN (not immunoreactive to VP or OT) are also immunoreactive for ␣-ENaC. In contrast, immunoreactivity to ␤-and ␥-ENaC is colocalized with VP alone within the MNCs. Furthermore, immunoreactivity for a known target for ENaC expression, the mineralcorticoid receptor (MR), is colocalized with both VP and OT in MNCs. Using single-cell RT-PCR, we detected mRNA for all three ENaC subunits and MR in cDNA libraries derived from single MNCs. In whole cell voltage clamp recordings, application of the ENaC blocker benzamil reversibly reduced a steady-state inward current and decreased cell membrane conductance approximately twofold. Finally, benzamil caused membrane hyperpolarization in a majority of VP and about one-half of OT neurons in both spontaneously firing and quiet cells. These results strongly suggest the presence of functional ENaCs that may affect the firing patterns of MNCs, which ultimately control the secretion of VP and OT. aldodsterone; vasopressin; oxytocin THE NEUROHYPOPHYSIAL HORMONES vasopressin (VP) and oxytocin (OT) are synthesized in the magnocellular neurons (MNCs) located within the paraventricular nucleus (PVN) and the supraoptic nucleus (SON) of the hypothalamus and released from the neurohypophysis into the general circulation in response to physiological demands. The secretion of VP increases in response to hyperosmolality, hypovolemia, and hypotension and produces antidiuretic and pressor effects (59). In addition to the well-known effects of OT during parturition and lactation, plasma OT also increases with hyperosmolality and hypernatremia (32) and induces natriuresis (13, 31).The non-voltage-dependent, amiloride-sensitive epithelial Na ϩ channels (ENaCs) are present in the apical membrane of epithelial cells in a variety of tissues, such as urinary bladder, renal collecting duct, distal colon, sweat and salivary glands, lung, and taste buds, and are known to mediate the transport of Na ϩ across epithelia (7, 21). Thus, together with the Na ϩ /K ϩ -ATPase present in the basal membrane of epithelial cells, ENaCs regulate transe...

show abstract

c-<i>fos</i> Expression in Vasopressin and Oxytocin Neurons Reveals Functional Heterogeneity within Magnocellular Neurons

Cited by 87 publications

References 23 publications

Delineation of responsive AVP-containing neurons to running stress in the hypothalamus

Delineation of responsive AVP-containing neurons to running stress in the hypothalamus

Blockade of NK3R signaling in the PVN decreases vasopressin and oxytocin release and c-Fos expression in the magnocellular neurons in response to hypotension

Epithelial Na⁺ sodium channels in magnocellular cells of the rat supraoptic and paraventricular nuclei

Contact Info

Product

Resources

About

c-<i>fos</i> Expression in Vasopressin and Oxytocin Neurons Reveals Functional Heterogeneity within Magnocellular Neurons

Cited by 87 publications

References 23 publications

Delineation of responsive AVP-containing neurons to running stress in the hypothalamus

Delineation of responsive AVP-containing neurons to running stress in the hypothalamus

Blockade of NK3R signaling in the PVN decreases vasopressin and oxytocin release and c-Fos expression in the magnocellular neurons in response to hypotension

Epithelial Na+ sodium channels in magnocellular cells of the rat supraoptic and paraventricular nuclei

Contact Info

Product

Resources

About

Epithelial Na⁺ sodium channels in magnocellular cells of the rat supraoptic and paraventricular nuclei