The in vitro swelling action of L-thyroxine on rat liver mitochondria as examined photometrically represents an acceleration of a process which the mitochondria are already inherently capable of undergoing spontaneously, as indicated by the identical kinetic characteristics and the extent of thyroxine-induced and spontaneous swelling, the nearly identical pH dependence, and the fact that sucros...

Triethyltin induces swelling of isolated rat liver mitochondria suspended in sucrose or KC1 media. This effect is not seen with brain mitochondria. Triethyltin swelling is only minimally reduced by EDTA or amytal but is prevented by 2 :Cdinitrophenol, cyanide or salicylate. The addition of adenosine trior diphosphate causes reversal of the swelling; this effect is potentiated by Mn2+ but not by...

Osmotic swelling of NIH3T3 mouse fibroblasts activates a bromoenol lactone (BEL)-sensitive taurine efflux, pointing to the involvement of a Ca(2+)-independent phospholipase A(2) (iPLA(2)) (Lambert IH. J Membr Biol 192: 19-32, 2003). We report that taurine efflux from NIH3T3 cells was not only increased by cell swelling but also decreased by cell shrinkage. Arachidonic acid release to the cell e...

During periods of high activity neurons are expected to swell due to the uptake of Cl(-). To find out whether leech Retzius neurons possess swelling-activated Cl(-) channels that facilitate Cl(-) efflux and, hence, volume recovery, we exposed the cells to hypotonic solutions. In hypotonic solutions, the cells slowly swelled but did not undergo a regulatory volume decrease. However, the cell vol...

The ion physiology of osmotic swelling and a consequent loss of epithelial patency was examined in the ovaries of the moth Hyalophora cecropia. After 30 min in the presence of an activator of cyclic-AMP-dependent protein kinase (PKA), the membrane potentials of both oocyte and follicle cells had hyperpolarized by approximately 30 %, cytoplasmic pH had dropped from 7.26 to 7.06, a normally low C...

Intestinal epithelial cells (IECs) play an indispensable role in maintaining body fluid balance partly through their ability to regulate anion/fluid secretion. Yet in various inflammatory gastrointestinal diseases, over-secretion of anions results in symptoms such as severe diarrhoea. Endogenous mediators, such as vasoactive intestinal peptide or prostaglandin E2 (PGE2), regulate intestinal ani...

In secretory cells, osmotic swelling of secretory granules is proposed to be an intermediate step in exocytic fusion of the granules with the plasma membrane. For osmotic swelling of the granule, a H (+) gradient generated by vacuolar-type H (+) -ATPase (V-ATPase) may be a driving force for accumulation of K (+) via its exchange with H (+) , concurrent with accumulation of Cl (-) and H(2)O. Her...

To elucidate the molecular mechanisms of the protective action of stigmatellin (an inhibitor of complex III of mitochondrial electron transport chain, mtETC) against the heavy metal-induced cytotoxicity, we tested its effectiveness against mitochondrial membrane permeabilization produced by heavy metal ions Cd²(+), Hg²(+), Cu²(+) and Zn²(+), as well as by Ca²(+) (in the presence of P(i)) or Se ...

The mechanism of activation of KCl cotransport has been examined in rabbit red blood cells. Previous work has provided evidence that a net dephosphorylation is required for activation of transport by cell swelling. In the present study okadaic acid, an inhibitor of protein phosphatases, was used to test this idea in more detail. We find that okadaic acid strongly inhibits swelling-stimulated KC...