Ultrastructure of the Epithelium of Terminal Bronchioles in Rabbits after the Administration of Acetylcholine
Abstract
In this experiment, the ultrastructure of the the epithelium of terminal terminal bronchioles was studied 5 and 20 minutes after intravenous administration of two different doses of acetylcholine. The administration of 0.5 me acetylcholine resulted in pathological alteration of the cytoplasm of epithelial cells recorded 5 and 20 minutes post exposure.
In the first phase, the secretion of Clara cells was inhibited. Twenty minutes after the acetylcholine administration, a mild stimulation of these cells to discharge the content of their secretory granules was observed.
After the administration of 0.1 mg acetylcholine, the signs of pathological alteration of the epithelial cell cytoplasm were mild. Twenty minutes post exposure, the findings did almost not differ from those in the epithelium of healthy control rabbits.
After an initial inhibition, the secretory activity of Clara cells was resumed and did not differ from that found in controls. No increased proliferation of epithelial cells was recorded in any experimental group.