Visualization of periendothelial cells in arterioles and capillaries by scanning electron microscopy of ultrasound treated and plastoid injected brains in rats.

The periendothelial cells of small arterioles and capillaries - smooth muscle cells and pericytes - are represented in the SEM after ultrasound treatment and by microcorrosion resin casts of the rat brain. The morphological appearance of the periendothelial cells revealed by both methods is nearly identical. In ultrasound treated tissue the cells of the medial tunic themselves become apparent as the adventitial material of the vascular wall is removed. Predominantly the pattern of arteriolar smooth muscles occurs in this manner. In casts the cells are represented and replaced by corresponding plastic structures. The pericytes of the capillaries and even the precapillary sphincters can be demonstrated in these preparations. SEM in conjunction with the applied techniques gives new knowledge of the cytoarchitecture and function of the vascular wall in microvessels.