Krumschnabel 2003 J Exp Biol

From Bioblast
Jump to: navigation, search
Publications in the MiPMap
Krumschnabel G, Gstir R, Manzl C, Prem C, Pafundo D, Schwarzbaum PJ (2003) Metabolic and ionic responses of trout hepatocytes to anisosmotic exposure. J Exp Biol 206:1799-1808.

» PMID:12728001 Open Access

Krumschnabel G, Gstir R, Manzl C, Prem C, Pafundo D, Schwarzbaum PJ (2003) J Exp Biol

Abstract: Trout hepatocytes exposed to hypo- or hyperosmotic conditions respond by swelling and shrinking, respectively, followed by regulatory volume changes that almost, although not completely, restore cell volume. These anisosmotic conditions have a significant impact on metabolic functions. In hyposmotic medium, oxygen consumption (.VO2) and glucose production rates were significantly reduced, whereas lactate accumulation was not significantly affected. By contrast, hyperosmotic conditions did not affect VO2 and lactate production but caused a sustained reduction in glucose production. Volume changes were also accompanied by alterations in intracellular free calcium ([Ca2+](i)). At the cell population level, hyposmotic exposure evoked a moderate and slowly developing increase in [Ca2+](i), whereas hyperosmolarity caused a pronounced and sustained increase, which peaked at the time of maximum cell shrinkage but clearly exceeded a mere concentration effect due to volume reduction. Responses of individual cells were highly variable in hyposmotic medium, with only 60% showing a clear increase in [Ca2+](i), while in hyperosmotic conditions all cells displayed elevated [Ca2+](i) levels. A decrease in intracellular pH (pHi) observed in hyposmotic medium was insensitive to EIPA, an inhibitor of Na(+)/H(+) exchange, and SITS, an inhibitor of Cl(-)/HCO(3)(-) exchange, but was prevented in Cl(-)-free medium. In hyperosmotic medium, pHi increased. This alkalinization did not occur under conditions of blocked Na(+)/H(+) exchange and was significantly diminished upon inhibition of Cl(-)/HCO(3)(-) exchange, suggesting an important role of these ion transporters in regulatory volume increase of trout hepatocytes

Keywords: rainbow trout, Oncorhynchus mykiss, hepatocyte, cell volume, oxygen consumption, intracellular free calcium, intracellular pH

O2k-Network Lab: AT Innsbruck Oroboros


Labels:


Organism: Fishes  Tissue;cell: Liver  Preparation: Intact cells 


Coupling state: ROUTINE 

HRR: Oxygraph-2k 

Environmental Physiology