Dynamic Interfacial Electrochemical Phenomena at Living Cell Membranes: Application to the Toad Urinary Bladder Membrane System

1977 ◽  
Vol 124 (11) ◽  
pp. 1697-1706 ◽  
Author(s):  
Arthur A. Pilla ◽  
Gary S. Margules
Keyword(s):  
Urinary Bladder ◽  
Living Cell ◽  
Cell Membranes ◽  
Membrane System ◽  
Toad Urinary Bladder ◽  
Electrochemical Phenomena

scholarly journals THE STRUCTURE OF THE ZONULA OCCLUDENS

1974 ◽  
Vol 60 (1) ◽  
pp. 168-180 ◽  
Author(s):  
James B. Wade ◽  
Morris J. Karnovsky
Keyword(s):  
Urinary Bladder ◽  
Tight Junction ◽  
Cell Membranes ◽  
Adjacent Cell ◽  
Toad Urinary Bladder ◽  
Zonula Occludens ◽  
Single Set

Replicas of freeze-fractured toad urinary bladder and gallbladder were analysed in an attempt to determine the fracturing properties and structure of the zonula occludens (tight junction). Chalcroft and Bullivant have proposed that the junction has a double set of fibrils with one set associated with each of the adjacent cell membranes. However, the fracturing pattern that is observed might also result from only a single set of fibrils which is shared by the adjacent membranes if fracturing occurred around either side of the fibrils. These two models predict quite different structures at regions of the junction where tranl sitions are made between face A and face B. The relative heights of face A and face B and the shape of the transition from face A to face B do not agree with that expected according to the two fibril model but agree exactly with that expected if only a single set of fibrils existed. Further evidence for the single fibril model is derived from fractures of the mucosa membrane which cross the junction to the membrane of the adjacent cell without deflection. Such fractures reveal a single ridge which appears to be identical to the juxtaluminal fibril of the junction. In addition, small ridges are occasionally found in place of the grooves on face B which, although not consistent with the double fibril model, is expected if the single fibril model were correct. Although alternative explanations might account for these observations, we believe that the simplest and most consistent explanation is that the zonula occludens fractures as would be expected of a single set of fibrils shared by adjacent cells.

Effect of aldosterone on abundance and phosphorylation kinetics of Na-K-ATPase of toad urinary bladder

1984 ◽  
Vol 246 (4) ◽  
pp. F509-F516
Author(s):  
C. S. Park ◽  
I. S. Edelman
Keyword(s):  
Urinary Bladder ◽  
Cell Membranes ◽  
Specific Activity ◽  
Short Circuit ◽  
Fold Increase ◽  
Sodium Deoxycholate ◽  
Kinetic Properties ◽  
Toad Urinary Bladder ◽  
Bladder Cell ◽  
Phosphorylation Reaction

The possibility was explored that aldosterone-dependent modulation of either the abundance or the kinetic properties of the Na+ pump (Na-K-ATPase) is involved in the mechanism of natriferic action on toad urinary bladder. Cell membranes from the epithelium of urinary bladders of toads were prepared by a sucrose-Ficoll step gradient method, which yielded a 10-fold increase in specific activity of plasma membrane marker enzymes and only minor contamination with other subcellular fractions. Phosphorylation of Na-K-ATPase by gamma-PO4 of [gamma-32P]ATP in the presence of Mg2+ was Na+ dependent, whereas dephosphorylation was K+ dependent. Km for phosphorylation by ATP was 3 X 10(-8) M and K1/2 (half-maximal stimulation) for Na+ was 13 +/- 2 mM. Pretreatment of cell membranes with sodium deoxycholate (DOC) increased the maximal extent of phosphorylation (Nmax) about threefold without changing the Km for ATP. Aldosterone (5 X 10(-8) M) stimulated transepithelial Na+ transport two- to threefold in 5 h but had no significant effect on Km for ATP in the phosphorylation reaction (with or without activation by DOC) or on the abundance of the enzyme inferred from Nmax of phosphorylation in the absence of activation by DOC. After pretreatment with DOC, average Nmax was 13% greater in the aldosterone-treated population. Regression analysis of these responses revealed no significant correlation between increments in short-circuit currents and Nmax values of phosphorylation with or without pretreatment with DOC.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of PKC isozymes in water transport in toad urinary bladder

1991 ◽  
Vol 49 ◽  
pp. 302-303
Author(s):  
A.J. Mia ◽  
L.X. Oakford ◽  
T. Yorio
Keyword(s):  
Urinary Bladder ◽  
Apical Membrane ◽  
Membrane Surface ◽  
Protein A ◽  
Cell Types ◽  
Leukemic Cells ◽  
Toad Urinary Bladder ◽  
Pkc Isozymes ◽  
Antibody Labeling

Protein kinase C (PKC) isozymes, when activated, are translocated to particulate membrane fractions for transport to the apical membrane surface in a variety of cell types. Evidence of PKC translocation was demonstrated in human megakaryoblastic leukemic cells, and in cardiac myocytes and fibroblasts, using FTTC immunofluorescent antibody labeling techniques. Recently, we reported immunogold localizations of PKC subtypes I and II in toad urinary bladder epithelia, following 60 min stimulation with Mezerein (MZ), a PKC activator, or antidiuretic hormone (ADH). Localization of isozyme subtypes I and n was carried out in separate grids using specific monoclonal antibodies with subsequent labeling with 20nm protein A-gold probes. Each PKC subtype was found to be distributed singularly and in discrete isolated patches in the cytosol as well as in the apical membrane domains. To determine if the PKC isozymes co-localized within the cell, a double immunogold labeling technique using single grids was utilized.

OSMOTIC INHIBITION OF THE NATRIFERIC RESPONSE OF THE TOAD URINARY BLADDER TO VASOPRESSIN

1975 ◽  
Vol 67 (1) ◽  
pp. 119-125
Author(s):  
P. J. BENTLEY
Keyword(s):  
Urinary Bladder ◽  
Water Movement ◽  
Short Circuit ◽  
Electrical Potential ◽  
Short Circuit Current ◽  
Toad Bladder ◽  
Toad Urinary Bladder ◽  
Electrical Potential Difference ◽  
Osmotic Gradient

SUMMARY The electrical potential difference and short-circuit current (scc, reflecting active transmural sodium transport) across the toad urinary bladder in vitro was unaffected by the presence of hypo-osmotic solutions bathing the mucosal (urinary) surface, providing that the transmural flow of water was small. Vasopressin increased the scc across the toad bladder (the natriferic response), but this stimulation was considerably reduced in the presence of a hypo-osmotic solution on the mucosal side, conditions under which water transfer across the membrane was also increased. This inhibition of the natriferic response did not depend on the direction of the water movement, for if the osmotic gradient was the opposite way to that which normally occurs, the response to vasopressin was still reduced. The natriferic response to cyclic AMP was also inhibited in the presence of an osmotic gradient. Aldosterone increased the scc and Na+ transport across the toad bladder but this response was not changed when an osmotic gradient was present. The physiological implications of these observations and the possible mechanisms involved are discussed.

Action of steroids on H+ and NH 4 + excretion in the toad urinary bladder

1979 ◽  
Vol 49 (4) ◽  
pp. 297-308 ◽  
Author(s):  
Loy W. Frazier ◽  
N. Y. Zachariah
Keyword(s):  
Urinary Bladder ◽  
Toad Urinary Bladder

scholarly journals Vasopressin-stimulated movement of drugs and uric acid across the toad urinary bladder

1976 ◽  
Vol 9 (1) ◽  
pp. 30-35 ◽  
Author(s):  
Sherman D. Levine ◽  
Nicholas Franki ◽  
Roland Einhorn ◽  
Richard M. Hays
Keyword(s):  
Uric Acid ◽  
Urinary Bladder ◽  
Toad Urinary Bladder
Sign in / Sign up

Export Citation Format

Share Document