The Role of Nitric Oxide and Vasp in Cytokine-Induced Renal Tubule Cell Shedding

2003 ◽  
Vol 104 (s49) ◽  
pp. 55P-55P
Author(s):  
Susan M. Crail ◽  
Thomas J. Evans
1977 ◽  
Vol 233 (4) ◽  
pp. F325-F332
Author(s):  
M. A. Linshaw ◽  
F. B. Stapleton ◽  
F. E. Cuppage ◽  
J. J. Grantham

Renal tubule cell volume is thought to be kept constant by a cation pump. When active transport is blocked, intracellular impermeant solutes cause cells to swell. Cell size is then determined by transmembrane hydrostatic and colloid osmotic forces. We studied the importance of passive transmembrane forces in determining cell size in isolated rabbit proximal straight tubules (PST). We blocked active solute transport with ouabain and evaluated subsequent changes in cell size by measuring outer diameter of nonperfused tubules. Tubules in a ouabain and 6 g/100 ml protein bath swelled only 40% above control. However, removal of the tubule basement membrane with collagenase dissipated a transmembrane hydrostatic pressure and caused more swelling. Final cell volume was determined largely by bath protein concentration. Tubules in ouabain and collagenase swelled enormously in hyponcotic protein, moderately in isoncotic protein, and could be shrunk below control in hyperoncotic protein. Intracellular colloid osmotic pressure was estimated to exceed 38 cmH20. We conclude that hydrostatic and colloid osmotic forces are major determinants of cell size in isolated PST treated with ouabain.


1992 ◽  
Vol 263 (5) ◽  
pp. R1086-R1092 ◽  
Author(s):  
D. A. Terreros ◽  
H. Kanli

Osmoregulatory Ca2+ signaling in hypotonic solutions was studied with videometric techniques in 158 proximal renal tubules isolated from the teleost Carassius auratus. Absence of extracellular Ca2+, hypoxia (23 mmHg), or NaCN (3 mM) did not alter regulatory volume decreases (RVD). Nevertheless, decrements of intracellular Ca2+ via the A23187 ionophore or after intracellular Ca2+ chelation with indo-1/AM (5 microM) inhibited RVD. In tubules depleted of Ca2+, RVD could only be fully elicited when intracellular Ca2+ pulses were given within 1 min after hypotonic stimulation. While inhibition of Ca2+ release from the endoplasmic reticulum (ER) with 8-(diethylamino)octyl 3,4,5-trimethoxybenzoate hydrochloride (TMB-8, 50 microM) blunted RVD, some of its effects could be reversed with the anion carrier tributyltin (1 microM). Dibutyryl adenosine 3',5'-cyclic monophosphate (cAMP, 0.5 and 1.0 mM) and forskolin (0.25 mM) also impeded RVD; however, their effects could be partially reversed with the K+ ionophore gramicidin (0.5 microM). In conclusion, in Carassius auratus proximal renal tubule cells, RVD is activated by an intracellular Ca2+ signal that likely emanates from the ER and not from the extracellular media or the mitochondrial Ca2+ pool. Ca2+ activation of a cAMP-modulated osmoregulatory K+ channel appears to play an important role.


2002 ◽  
Vol 30 (6) ◽  
pp. 681-686 ◽  
Author(s):  
John C. Seely ◽  
Joseph K. Haseman ◽  
Abraham Nyska ◽  
Douglas C. Wolf ◽  
Jeffrey I. Everitt ◽  
...  

1980 ◽  
Vol 239 (6) ◽  
pp. F571-F577 ◽  
Author(s):  
M. A. Linshaw

Renal tubule cell volume is thought to be kept constant by a cation pump. Ouabain, by inhibiting Na+-K+-ATPase, blocks cation transport with resultant cell swelling, but the degree of swelling is less than expected were active cation transport completely inhibited. Although the relatively rigid tubule basement membrane may limit swelling of ouabain-treated tubules, some investigators have alternatively postulated that an energy-dependent ouabain-insensitive cation pump regulates cell size. This notion derives from studies of renal cortical slices in which metabolic inhibitors such as 2,4-dinitrophenol (DNP) cause more swelling than ouabain. We blocked cellular metabolism of isolated rabbit proximal straight tubules by adding metabolic inhibitors to or removing acetate and glucose (energy substrate) from the bathing medium and evaluated subsequent changes in cell size by measuring outer diameter of nonperfused tubules. In isotonic medium, cell volume increased 36% with addition of 10(-4) M ouabain, 40% with 10(-2) M DNP, 46% with 10(-3) M cyanide, 39% with ouabain + DNP + cyanide, and 37% with removal of bath substrate (P = NS). We conclude that renal tubule cell volume is not regulated by a unique-ouabain-insensitive cation pump.


Cryobiology ◽  
2021 ◽  
Vol 103 ◽  
pp. 181
Author(s):  
Heather E. Tomalty ◽  
Virginia K. Walker ◽  
Peter L. Davies

Sign in / Sign up

Export Citation Format

Share Document