Journal of Dental Research, Vol 66, 1303-1309, Copyright © 1987 by International & American Associations for Dental Research Online Journals
Morphological changes of intercellular junctions in the rat submandibular gland treated by long-term repeated administration of isoproterenol
T. Inoue, H. Yamane, T. Yamamura and M. Shimono
Long-term repeated administration of isoproterenol (IPR) 2 mg/100 g bw,
once daily for ten days, resulted in morphological changes in the
intercellular junctions of rat submandibular glands, which were
investigated by means of the freeze-fracture technique. A significantly
increased number of tight-junctional strands was present. These junctional
strands extended much deeper toward the basal membrane than those in normal
acinar cells. The basal frontier strands that branched from the networks of
tight junctions were elongated and had either free-endings or terminal
loops, which were more frequently observed in the IPR-treated acinar cells
than in untreated acinar cells. Some of the strands of tight junctions were
connected to small gap junctions. The diameters of gap junctions were not
significantly different from those of control acinar cells. However, smooth
areas devoid of particles were found intermingling with the usual packed
particles in irregularly shaped small gap junctions. There was no
significant difference between the desmosomes of IPR-treated and untreated
acinar cells, in terms of either morphology or distribution. These changes
in junctional morphology in the IPR-treated acinar cells resemble those
seen in salivary glands during development, and in some experimental
conditions including tumorous changes.
