[Evolution of the structural and cytochemical organization of the taste buds in vertebrates]

Ultrastructural and cytochemical organization of the receptors, supporting and basal cells of vertebrate taste buds are described. The receptor cells of all the vertebrates are characterized by single large microvillar process, well developed smooth endoplasmic reticulum and synaptic contacts with afferent and efferent nerve endings. A number of enzymes and acid mucopolysaccharides were demonstrated on the membrane of the microvillar process. At the synaptic area, AChE activity and monoamines are revealed. Besides, less numerous type of the receptor cells with several smaller microvillar processes are described in the taste buds. The supporting cells are characterized by numerous secretory granules and bundles of longitudinally oriented tonofibrils. The basal cells lie on the basal membrane and have no contact with the environment. Possible contribution of each type of the taste bud cells into gustation is discussed.