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Biomedical subjects

Y KANNO

Publications and source records attributed to Y KANNO.

12 recordsLinked to original sources
PubMed1964

INTERCELLULAR ELECTRICAL COUPLING AT A FORMING MEMBRANE JUNCTION IN A DIVIDING CELL.

Ion communication between the halves (blastomere) of a dividing cell (Asterias forbesi egg), as determined electrically, diminishes progressively during division as a cell membrane junction forms at the plane of cleavage. Virtually all communication is lost towards the end of division by the time the first intercellular space becomes continuous with the exterior. Resting membrane potentials in both cell halves are essentially equal and constant throughout division.

Animals↗
PubMed1964

INTERCELLULAR DIFFUSION.

Fluorescein-sodium, a fluorescent tracer whose molecular weight is 376, diffuses rather freely from the interior of one cell to another in a gland epithelium (Drosophila) but does not diffuse along the intercellular space to the exterior. The permeability of the junctional surfaces of the cell membranes appears to be high, in contrast to the nonjunctional surfaces and intercellular spaces which represent strong diffusion barriers.

Animals↗
PubMed1964

STUDIES ON AN EPITHELIAL (GLAND) CELL JUNCTION. I. MODIFICATIONS OF SURFACE MEMBRANE PERMEABILITY.

Membrane permeability of an epithelial cell junction (Drosophila salivary gland) was examined with intracellular microelectrodes and with fluorescent tracers. In contrast to the non-junctional cell membrane surface, which has a low permeability to ions (10(-4) mho/cm(2)), the junctional membrane surface is highly permeable. In fact, it introduces no substantial restriction to ion flow beyond that in the cytoplasm; the resistance through a chain of cells (150 ohm cm) is only slightly greater than in extruded cytoplasm (100 ohm cm). The diffusion resistance along the intercellular space to the exterior, on the other hand, is very high. Here, there exists an ion barrier of, at least, 10(4) ohm cm(2). As a result, small ions and fluorescein move rather freely from one cell to the next, but do not leak appreciably through the intercellular space to the exterior. The organ here, rather than the single cell, appears to be the unit of ion environment. The possible underlying structural aspects are discussed.

Animals↗
PubMed1963

SOME ELECTRICAL PROPERTIES OF A NUCLEAR MEMBRANE EXAMINED WITH A MICROELECTRODE.

Electrical potential and resistance were measured with microelectrodes in in situ and isolated nuclei of gland cells of Drosophila flavorepleta. The nucleus-cytoplasm boundary was found to be rather impermeable to ion diffusion. It presents a resistance of the order of 1 ohm cm(2) and sustains a "resting" potential, the nucleoplasm being about 15 mv negative with respect to the cytoplasm. Both the resistance and potential appear to be associated with the nuclear membrane: the potential declines to zero and the resistance to a fraction of its original value, when the membrane is perforated experimentally.

Animals↗