Osmotic shock
5386941
215715662
2008-05-29T11:40:17Z
DOI bot
6652755
Citation maintenance. Initiated by [[User:Tarun2k|Tarun2k]]. You can [[WP:DOI|use this bot]] yourself! Please [[User:DOI_bot/bugs|report any bugs]].
{{Mergeto|Osmosis|date=December 2007}}
'''Osmotic shock''' or '''osmotic stress''' is a sudden change in the [[Solution|solute]] concentration around a [[Cell (biology)|cell]], causing a rapid change in the movement of water across its [[cell membrane]]. Under conditions of high concentrations of either [[salt]]s, [[substrate (biology)|substrates]] or any solute in the [[supernatant]] water is drawn out of the cells through [[osmosis]]. This also inhibits the transport of substrates and cofactors into the cell thus “shocking” the cell. Alternatively, at low concentrations of solutes, water enters the cell in large amounts, causing it to swell and either burst or undergo [[apoptosis]].<ref>{{cite journal |author=Lang KS, Lang PA, Bauer C, ''et al'' |title=Mechanisms of suicidal erythrocyte death |journal=Cell. Physiol. Biochem. |volume=15 |issue=5 |pages=195–202 |year=2005 |pmid=15956782 |doi=10.1159/000086406}}</ref>
All organisms have mechanisms to respond to osmotic shock, with sensors and [[signal transduction]] networks providing information to the cell about the [[Osmole (unit)|osmolarity]] of its surroundings,<ref>{{cite journal |author=Kültz D, Burg M |title=Evolution of osmotic stress signaling via MAP kinase cascades |journal=J. Exp. Biol. |volume=201 |issue=Pt 22 |pages=3015–21 |year=1998 |pmid=9787121 |url=http://jeb.biologists.org/cgi/reprint/201/22/3015}}</ref> these signals activate responses to deal with extreme conditions.<ref>{{cite journal |author=Kültz D |title=Osmotic stress sensing and signaling in animals |journal=FEBS journal |volume=274 |issue=22 |pages=5781–5781 |year=2007 |pmid=17944944 |doi=10.1111/j.1742-4658.2007.06097.x}}</ref> Although single-celled organisms are more vulnerable to osmotic shock, since they are directly exposed to their environment, cells in large animals such as [[mammals]] still suffer these stresses under some conditions.<ref>{{cite journal |author=Ho SN |title=Intracellular water homeostasis and the mammalian cellular osmotic stress response |journal=J. Cell. Physiol. |volume=206 |issue=1 |pages=9–15 |year=2006 |pmid=15965902 |doi=10.1002/jcp.20445}}</ref>
Calcium acts as one of the primary regulators of osmotic stress. Intracellular calcium levels rise during hypo-osmotic and hyper-osmotic stresses. During hyper-osmotic stress extracellular [[albumin]] binds calcium.
===Recovery and Tolerance Mechanisms for Hyper-osmotic Stress===
Extracellular sequestering of [[Calcium]] by blood [[Albumin]]
Transient intracellular Ca<sup>2+</sup> increase.
===Recovery and Tolerance Mechanisms for Hypo-osmotic Stress===
Intracellular Ca<sup>2+</sup> increase and Extracellular ATP Release<ref>{{cite journal |author=Hélène Ollivier, Karine Pichavant-Rafini, Eneour Puill-Stephan, Patrick Calvès, Liliane Nonnotte and Guy Nonnotte |title=Effects of hypo-osmotic stress on ATP release in isolated turbot (Scophthalmus maximus) hepatocytes |journal=Biol. Cell |volume=98 |issue=7 |pages=427–437 |year=2006 |pmid=16519627 |doi=10.1042/BC20050077}}</ref>
Calcium dependent efflux of the osmolyte [[Taurine]]. Extracellular calcium removal was found to prevent Taurine efflux by 50%, and removal of extracellular Ca<sup>2+</sup> and simultaneous depletion of intracellular Ca<sup>2+</sup> stores with [[thapsigargin]] decreased it by 85%.<ref>{{cite journal |author=Olivero P, Stutzin A. |title=Calcium modulates osmosensitive taurine efflux in HeLa cells. |journal=Neurochem Res. |volume=29 |issue=1 |pages=169–76 |year=2004 |pmid=14992276 |doi=10.1023/B:NERE.0000010446.50158.8d}}</ref>.
===Osmotic Damage in Humans===
See [[Osmotic_demyelination_syndrome]]
==References==
{{reflist}}
==See also==
* [[Osmolyte]]
* Myo-[[Inositol]]
* [[Taurine]] and [[Taurine-transporting ATPase]]
* [[Creatine]]
* [[Betaines]]
* [[Trimethylglycine]] - A Betaine and metabolite of [[Choline]]
* [[Sorbitol]]
* Glycerophosphocholine
{{biology-stub}}