Communicating junctions and calmodulin: Inhibition of electrical uncoupling inXenopus embryo by calmidazolium

1984 ◽  
Vol 81 (1) ◽  
pp. 49-58 ◽  
Author(s):  
Camillo Peracchia
Keyword(s):  
Electrical Uncoupling ◽  
Communicating Junctions

Calmodulin-mediated gating of lens gap junction channels in vesicles

1984 ◽  
Vol 42 ◽  
pp. 134-137
Author(s):  
Camillo Peracchia ◽  
Stephen J. Girsch
Keyword(s):  
Gap Junctions ◽  
Freeze Fracture ◽  
Orthogonal Arrays ◽  
Eye Lens ◽  
Lens Fiber ◽  
Cell Coupling ◽  
Particle Spacing ◽  
Fiber Cells ◽  
Gap Junction Channels ◽  
Communicating Junctions

The fiber cells of eye lens communicate directly with each other by exchanging ions, dyes and metabolites. In most tissues this type of communication (cell coupling) is mediated by gap junctions. In the lens, the fiber cells are extensively interconnected by junctions. However, lens junctions, although morphologically similar to gap junctions, differ from them in a number of structural, biochemical and immunological features. Like gap junctions, lens junctions are regions of close cell-to-cell apposition. Unlike gap junctions, however, the extracellular gap is apparently absent in lens junctions, such that their thickness is approximately 2 nm smaller than that of typical gap junctions (Fig. 1,c). In freeze-fracture replicas, the particles of control lens junctions are more loosely packed than those of typical gap junctions (Fig. 1,a) and crystallize, when exposed to uncoupling agents such as Ca++, or H+, into pseudo-hexagonal, rhombic (Fig. 1,b) and orthogonal arrays with a particle-to-particle spacing of 6.5 nm. Because of these differences, questions have been raised about the interpretation of the lens junctions as communicating junctions, in spite of the fact that they are the only junctions interlinking lens fiber cells.

Electrogastrography can recognize gastric electrical uncoupling in dogs

1997 ◽  
Vol 112 (6) ◽  
pp. 2006-2011 ◽  
Author(s):  
MP Mintchev ◽  
SJ Otto ◽  
KL Bowes
Keyword(s):  
Electrical Uncoupling ◽  
Gastric Electrical Uncoupling

The mechanism of T cell mediated cytotoxicity IV. Studies on communicating junctions between cells in contact

1977 ◽  
Vol 196 (1122) ◽  
pp. 73-84 ◽  
Keyword(s):  
T Cell ◽  
Mammalian Cells ◽  
Cytotoxic T Cells ◽  
Diploid Cell ◽  
Target Cells ◽  
Cytotoxic Lymphocytes ◽  
Communicating Junctions ◽  
Unique System ◽  
Pass Through ◽  
Autoradiographic Technique

A modified autoradiographic technique has been developed which makes it possible to demonstrate the intercellular transfer of diffusible molecules through communicating junctions. This technique has been used to decide whether or not there is a cytoplasmic union between cytotoxic lymphocytes and the target cells they destroy. The transfer of 51 Cr, [ 3 H]uridine and [ 3 H]choline has been demonstrated between human diploid cell line cells (MRC 5) in contact. This has provided a system in which the techniques could be assessed. The demonstration that 51 Cr can pass through communicating junctions provides a unique system for the investigations of these structures. Despite the fact that all three labels could transfer between MRC 5 cells in contact, no transfer between cytotoxic T cells and P815 target cells could be demonstrated during a cytotoxic reaction. The reported transfer of fluorescein can probably be attributed to the transfer of fluorescein ester via the extracellular space. It is concluded, therefore, that communicating junctions of the type that can form between certain mammalian cells in contact do not contribute to the mechanism of T cell cytotoxicity.

Electrical properties of the gap junctional membrane studied in rat liver cell pairs

1988 ◽  
Vol 254 (2) ◽  
pp. C226-C234 ◽  
Author(s):  
E. C. Reverdin ◽  
R. Weingart
Keyword(s):  
Electrical Properties ◽  
Gap Junction ◽  
Rat Liver ◽  
Time Range ◽  
Voltage Gradient ◽  
Voltage Range ◽  
Cell Pair ◽  
Adult Rat ◽  
Electrical Uncoupling ◽  
Gap Junctional

Cell pairs isolated from adult rat liver were used to study the electrical properties of gap junctions. Each cell of a cell pair was connected to a suction pipette so as to enable whole cell tight-seal recording. A double voltage-clamp approach was adopted to control the voltage gradient across the gap junction and measure the transjunctional current. The current-voltage relationship of the gap junctional membrane was linear over the voltage range tested (+/- 50 m V). Under control conditions, the resistance of the gap junction, rj, was 15 M omega (n = 27; range, 4.6 to 45.8 M omega), corresponding to a conductance gj of 67 nS. rj was insensitive to the nonjunctional membrane potential, Vm (voltage range,-90 m V to + 40 m V). There was no indication of a time-dependent gating of rj (time range, 20 ms to 10 s). Dialysis with 1 mM CaCl2 produced irreversible electrical uncoupling without affecting the linearity of the relationship Vj/Ij.

R 56865 Delays Cellular Electrical Uncoupling in Ischemic Rabbit Papillary Muscle

1993 ◽  
Vol 25 (9) ◽  
pp. 1059-1066 ◽  
Author(s):  
Hanno L. Tan ◽  
Alexandra O. Netea ◽  
Mengalvio E. Sleeswijk ◽  
Pilar Mazón ◽  
Ruben Coronel ◽  
...  
Keyword(s):  
Papillary Muscle ◽  
Rabbit Papillary Muscle ◽  
Electrical Uncoupling ◽  
R 56865

A correlative freeze-etch and electrophysiological study of communicating junctions in crystalline lenses

1985 ◽  
Vol 4 (11) ◽  
pp. 1145-1153 ◽  
Author(s):  
J. R. Kuszak ◽  
Y. H. Shek ◽  
K. C. Carney ◽  
J. L. Rae
Keyword(s):  
Electrophysiological Study ◽  
Communicating Junctions
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