Scanning electron microscopy of nasal arterioles effected by vasoactive agents.

Morphological changes in nasal blood vessels induced by alpha- and beta-adrenergic and cholinergic agonists were studied under a scanning electron microscope after removal of extracellular connective tissue and the basal lamina. Arterioles were constricted and dilatated following topical application of alpha-adrenergic and cholinergic agonists. Distinctive morphological changes were observed on their smooth muscle cells. Smooth muscle cells of constricted arterioles had a rugged surface with numerous fine invaginations. However, in dilatated arterioles the cells had a smooth surface and intercellular spaces were clearly revealed. No remarkable changes were produced in smooth muscle cells by the beta-adrenergic agonist. It is concluded that nasal arterioles are sensitive to alpha-adrenergic and cholinergic stimulation but not to beta-adrenergic stimulation.