Osmosensitivity of prolactin cells is enhanced by the water channel aquaporin-3 in a euryhaline Mozambique tilapia (Oreochromis mossambicus)

2009 ◽  
Vol 296 (2) ◽  
pp. R446-R453 ◽  
Author(s):  
Soichi Watanabe ◽  
Tetsuya Hirano ◽  
E. Gordon Grau ◽  
Toyoji Kaneko
Keyword(s):  
Cell Volume ◽  
Significant Contribution ◽  
Water Channel ◽  
Inhibitory Effect ◽  
Prolactin Cells ◽  
Volume Increase ◽  
Aquaporin 3 ◽  
Mozambique Tilapia ◽  
Immunohistochemical Studies ◽  
Rostral Pars Distalis

In teleost fish, prolactin (PRL) has important actions in the regulation of salt and water balances in freshwater (FW) fish. Consistent with this role, the release of PRL from the pituitary of the Mozambique tilapia is stimulated as extracellular osmolality is reduced. Stretch-activated calcium-permeant ion channels appear to be responsible for the initiation of the signal transduction that leads to increased PRL release when PRL cells are exposed to reductions in extracellular osmolality. In this study, we examined a possible involvement of the aquaporin-3 (AQP3) water channel in this osmoreceptive mechanism in PRL cells of the tilapia. AQP3 expression levels in the rostral pars distalis of the pituitary, consisting predominantly of PRL cells, were higher in fish adapted to FW than in seawater (SW)-adapted fish. Immunohistochemical studies revealed that AQP3 is located in the cell membrane and perinuclear region of PRL cells, with more intense immunosignals in PRL cells of FW-adapted fish than in those of SW fish. In FW PRL cells, the magnitude of hyposmoticity-induced cell volume increase was greater than that seen in SW PRL cells. Mercury, a potent inhibitor of AQP3, inhibited hyposmoticity-induced cell volume increase and PRL release from FW PRL cells. The inhibitory effect of mercury was partially restored by β-mercaptoethanol, whereas no effect of mercury was observed on PRL release stimulated by a depolarizing concentration of KCl, which induces Ca2+ influx and stimulates the subsequent Ca2+-signaling pathway. These results indicate significant contribution of AQP3 to osmoreception in PRL cells in FW-adapted tilapia.

scholarly journals Tilapia Prolactin Cells are Thermosensitive Osmoreceptors

2021 ◽  
Author(s):  
Daniel W. Woo ◽  
G.H.T. Malintha ◽  
Fritzie T. Celino-Brady ◽  
Yoko Yamaguchi ◽  
Jason P. Breves ◽  
...  
Keyword(s):  
Channel Blocker ◽  
Water Channel ◽  
Oreochromis Mossambicus ◽  
Mrna Levels ◽  
Pars Distalis ◽  
Prolactin Cells ◽  
A Cell ◽  
Euryhaline Teleost ◽  
Dependent Pathway ◽  
Rostral Pars Distalis

Abstract Prolactin (PRL) cells within the rostral pars distalis (RPD) of the euryhaline teleost tilapia, Oreochromis mossambicus, rapidly respond to a hyposmotic stimulus by releasing two distinct PRL isoforms, PRL188 and PRL177. Here, we describe how environmentally relevant temperatures affect the release and mRNA levels of PRL188 and PRL177 from RPDs and dispersed PRL cells. When applied under isosmotic conditions (330 mOsm/kg), a 6 °C rise in temperature stimulated the release of PRL188 and PRL177 from both RPDs and dispersed PRL cells under perifusion. When exposed to this same change in temperature, ~50% of dispersed PRL cells gradually increased in volume by ~8%, a response partially inhibited by the water channel blocker, HgCl2. Following their response to increased temperature, PRL cells remained responsive to a hyposmotic stimulus (280 mOsm/kg). The mRNA expression of transient potential vanilloid 4, a Ca2+-channel involved in hyposomotically-induced PRL release, was elevated in response to a rise in temperature in dispersed PRL cells and RPDs at 6 and 24 h, respectively; prl188 and prl177 mRNAs were unaffected. Our findings indicate that thermosensitive PRL release is mediated, at least partially, through a cell-volume dependent pathway similar to how osmoreceptive PRL release is achieved.

scholarly journals Regulation of Plasma Membrane Nanodomains of the Water Channel Aquaporin-3 Revealed by Fixed and Live Photoactivated Localization Microscopy

Nano Letters ◽  
2018 ◽  
Vol 19 (2) ◽  
pp. 699-707 ◽  
Author(s):  
Eva C. Arnspang ◽  
Prabuddha Sengupta ◽  
Kim I. Mortensen ◽  
Helene H. Jensen ◽  
Ute Hahn ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Water Channel ◽  
Localization Microscopy ◽  
Aquaporin 3 ◽  
Photoactivated Localization Microscopy

Diffusion of Carbon into RE2Fe17(RE=RARE Earth) Lattice: A High Temperature Approach

1998 ◽  
Vol 527 ◽  
Author(s):  
M. Venkatesan ◽  
U.V. Varadaraju ◽  
K.V.S. Rama Rao
Keyword(s):  
Curie Temperature ◽  
Cell Volume ◽  
Unit Cell Volume ◽  
Uniaxial Anisotropy ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Volume Increase ◽  
Melting Technique ◽  
Interstitial Carbides ◽  
Ga Substitution

ABSTRACTThe interstitial carbides HoErFe15Ga2Cy (y=0,0.5,1.0,1.5,2.0) were synthesized by are melting technique and characterized by X-ray diffraction and magnetization measurements. The hexagonal Th2Ni17 type structure persisted in all compounds. Both the Curie temperature TC and unit cell volume v are found to increase monotonically with increasing carbon concentration. The unit cell volume increase of Ga substituted carbide HoErFe15Ga2C2.0 is around 6.1% compared to HoErFe17. The Curie temperature increase is mainly due to the strengthening of exchange interaction. The Ga substitution is found to not only help the formation of single phase but also enhance the uniaxial anisotropy.

Effect of isosmotic removal of extracellular Ca2+ and of membrane potential on cell volume in muscle cells

1994 ◽  
Vol 267 (3) ◽  
pp. C768-C775 ◽  
Author(s):  
C. Pena-Rasgado ◽  
K. D. McGruder ◽  
J. C. Summers ◽  
H. Rasgado-Flores
Keyword(s):  
Membrane Potential ◽  
Sarcoplasmic Reticulum ◽  
Cell Volume ◽  
Muscle Cells ◽  
Membrane Depolarization ◽  
Volume Reduction ◽  
Sensitive Volume ◽  
Volume Increase ◽  
Dependent Cell ◽  
In Cells

Isosmotic removal of extracellular Ca2+ (Cao) and changes in membrane potential (Vm) are frequently performed manipulations. Using isolated voltage-clamped barnacle muscle cells, we studied the effect of these manipulations on isosmotic cell volume. Replacing Cao by Mg2+ induced 1) verapamil-sensitive extracellular Na(+)-dependent membrane depolarization, 2) membrane depolarization-dependent cell volume reduction in cells whose sarcoplasmic reticulum (SR) was presumably loaded with Ca2+ [intracellular Ca2+ (Cai)-loaded cells], and 3) cell volume increase in cells whose SR was presumably depleted of Ca2+ (Cai-depleted cells) or in Cai-loaded cells whose Vm was held constant. Membrane depolarization induced 1) volume reduction in Cai-loaded cells or 2) verapamil-sensitive volume increase in Cai-depleted cells. This suggests tha, in Cai-loaded cells, membrane depolarization induces SR Ca2+ release, which in turn promotes volume reduction. Conversely, in Cai-depleted cells, the depolarization activates Na+ influx through a verapamil-sensitive pathway leading to the volume increase. This pathway is also revealed when Cao is removed in either Cai-depleted cells or in cells whose Vm is held constant.

scholarly journals Inhibition of Aquaporin-3 Water Channel in the Colon Induces Diarrhea

2012 ◽  
Vol 35 (6) ◽  
pp. 957-962 ◽  
Author(s):  
Nobutomo Ikarashi ◽  
Risako Kon ◽  
Tomohiko Iizasa ◽  
Noriko Suzuki ◽  
Reiko Hiruma ◽  
...  
Keyword(s):  
Water Channel ◽  
Aquaporin 3

The role of water channel aquaporin 3 in the mechanism of TNF-α-mediated proinflammatory events: Implication in periodontal inflammation

2008 ◽  
Vol 217 (2) ◽  
pp. 338-349 ◽  
Author(s):  
S. Tancharoen ◽  
T. Matsuyama ◽  
K. Abeyama ◽  
K. Matsushita ◽  
K. Kawahara ◽  
...  
Keyword(s):  
Water Channel ◽  
Aquaporin 3 ◽  
Periodontal Inflammation ◽  
Tnf Α

Cell volume increase and extracellular Ca2+ are needed for hyposmotically induced prolactin release in tilapia

2003 ◽  
Vol 284 (5) ◽  
pp. C1280-C1289 ◽  
Author(s):  
A. P. Seale ◽  
N. H. Richman ◽  
T. Hirano ◽  
I. Cooke ◽  
E. G. Grau
Keyword(s):  
Cell Volume ◽  
Regulatory Volume Decrease ◽  
Volume Increase ◽  
Solute Retention ◽  
Intracellular Ca ◽  
Freshwater Adaptation ◽  
Euryhaline Teleost ◽  
Volume Decrease

In the tilapia ( Oreochromis mossambicus), as in many euryhaline teleost fish, prolactin (PRL) plays a central role in freshwater adaptation, acting on osmoregulatory surfaces to reduce ion and water permeability and increase solute retention. Consistent with these actions, PRL release is stimulated as extracellular osmolality is reduced both in vivo and in vitro. In the current experiments, a perfusion system utilizing dispersed PRL cells was developed for permitting the simultaneous measurement of cell volume and PRL release. Intracellular Ca2+ was monitored using fura 2-loaded cells under the same conditions. When PRL cells were exposed to hyposmotic medium, an increase in PRL cell volume preceded the increase in PRL release. Cell volume increased in proportion to decreases of 15 and 30% in osmolality. However, regulatory volume decrease was clearly seen only after a 30% reduction. The hyposmotically induced PRL release was sharply reduced in Ca2+-deleted hyposmotic medium, although cell volume changes were identical to those observed in normal hyposmotic medium. In most cells, a rise in intracellular Ca2+ concentration ([Ca2+]i) during hyposmotic stimulation was dependent on the availability of extracellular Ca2+, although small transient increases in [Ca2+]i were sometimes observed upon introduction of Ca2+-deleted media of the same or reduced osmolality. These results indicate that an increase in cell size is a critical step in the transduction of an osmotic signal into PRL release and that the hyposmotically induced increase in PRL release is greatly dependent on extracellular Ca2+.

scholarly journals Biostimulants isolated or integrated with paclobutrazol as tomato development triggering factors

2020 ◽  
pp. 255
Author(s):  
Talles Victor Silva ◽  
Hyrandir Cabral de Melo ◽  
Monita Fiori de Abreu Tarazi ◽  
Luis Carlos Cunha Junior ◽  
Luiz Fernandes Cardoso Campos ◽  
...  
Keyword(s):  
Plant Growth ◽  
Plant Growth Regulator ◽  
Dry Mass ◽  
Inhibitory Effect ◽  
Volume Increase ◽  
Solanum Lycopersicum L ◽  
Leaf Dry Mass ◽  
Crop Field ◽  
Hormonal Balance ◽  
Number Of Leaves

Plant biostimulants are substances with different chemistry or biological composition whose, when applied to plants, can favour their development mainly by enhance nutrient uptake or nutrition efficiency and also can alter plant hormonal balance. Paclobutrazol (PBZ) is a retardant plant growth regulator which promotes reduction on stem internodes culminating in shorter plants. The integration of both, biostimulants and PBZ, can lead better development of plants by at same time favour the nutrition performance of shorter plants. Although some farmers already have used these substances in crop field, alone or in combination, there is a great lack of scientific studies to verify the real efficiency of the biostimulants available in market. The aim of this study was to study the effect of different biostimulants on the morphometrical and physiological aspects of tomato when applied in combination or not with paclobutrazol in Solanum lycopersicum L., hybrid H9553. The biostimulants used were Stimulate®, Serenade®, EnerVig®, Px-Fertil®, Vorax®, Liqui-plex® and DuoOrgano+®. PBZ reduced plant height and, unlike expected, no one of the biostimulants favoured volume increase or dry mass of roots. However, all biostimulants favoured the accumulation of leaf dry mass, with no increase in the number of leaves or net photosynthetic rate per specific leaf area. When isolated, or in interaction with biostimulants, the PBZ generated stimulatory or inhibitory effect on expression of the parameters evaluated, depending on the organ and its age, and acted in synergism or antagonism with the biostimulants, depending on the substance in question.

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