Journal of Dental Research, Vol 70, 1456-1461, Copyright © 1991 by International & American Associations for Dental Research Online Journals
A scanning electron microscopic study of the contraction of vascular wall cells in dog dental pulp
T. Iijima, J. Q. Zhang, T. Goto, T. Kondo and T. Tanaka
Department of Oral Anatomy, Faculty of Dentistry, Kyushu University 61, Fukuoka, Japan.
Ultrastructural changes in vascular wall cells in dog dental pulp after
removal of connective tissue components were studied by scanning electron
microscopy following administration of norepinephrine (0.2 mg/kg).
Contracted smooth-muscle cells were frequently seen in arterioles of all
sizes. The surfaces of these cells were highly irregular with numerous
evaginations and invaginations, varying considerably in configuration and
size. Many evaginations ran longitudinally or obliquely to the long axis of
the vessel. Some meandering evaginations were also observed as, rarely,
were small spherical or bulbous projections. Spidery smooth-muscle cells
frequently seen in the tunica media of terminal arterioles and thought to
be primitive smooth-muscle cells exhibited fewer irregularities than the
typical spindle-shaped smooth-muscle cells beneath them. Pericytes in the
larger post-capillary venules (20 microns or larger in diameter) often
showed evaginations and invaginations, mainly running parallel to the
vessel axis. On the other hand, no surface irregularities could be seen in
pericytes of either the smaller post-capillary venules (less than 20
microns in diameter) or the capillaries, although occasional evaginations
running parallel to the vessel axis were noted on the outer surface of the
endothelium.
