Experimental production of longitudinal smooth muscle cells in the intima of muscular arteries.

Longitudinal smooth muscle cells were produced in the intima of muscular arteries in order to determine their method of development. Longitudinally arranged smooth muscle cells are present regularly in the intima of muscular arteries in man. Although absent in mesenteric arteries of the rat, layers of these cells were formed in these arteries after the insertion of a ligature through the mesentery. The resulting damage to, and subsequent repair of the arteries in the fibrotic area around the ligature apparently induced the development of longitudinal, intimal smooth muscle cells. When the mesentery was fixed to the diaphragm in such a way that it followd its respiratory movements with intermittent stretching of the mesenteric arteries, intimal smooth muscle cells developed only when the ligature through the mesentery caused local damage. Intermittent stretching as such had no effect.