ISSN:
0003-276X
Schlagwort(e):
Life and Medical Sciences
;
Cell & Developmental Biology
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Medizin
Notizen:
An intercellular junction known as the nexus has been identified in developing granulosa tissue of rat ovaries. Nexuses are common in Graafian follicles of mature cycling rats and in similar follicles of immature animals stimulated by exogenous gonadotrophins. The angle at which the plane of section intersects a nexus significantly governs its internal appearance. Within obliquely cut nexuses there is often a cross-striated pattern of uniform lines in specimens prepared by conventional fixation and staining procedures. These lines could be significant because they may represent points of continuity between communicating cells.Two forms of nexuses are observed. The abutment form is found at cell surfaces, is continuous with plasma membranes, and is frequently associated with cell processes. The other form of nexus is ring-shaped and appears free within the cytoplasm. These circular profiles probably represent transverse views through nexus-girdled cell processes as well as nexus-bound spheres which may have pinched off the processes. Since the profiles from the two sources are ordinarily indistinguishable, both are designated “annular nexuses” even though some may be cell inclusions. Lanthanum tracer can percolate into the central region of abutment nexuses but is absent from the large majority of annular nexuses, suggesting that many of them are isolated from the extracellular space. Reconstruction of serial sections reveals that some annuli are parts of cell inclusions. Sphere formation could be a means of removing nexuses from cell surfaces.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/ar.1091750110
