Ultrastructure of granule secretion in salivary glands of Argas (Persicargas) arboreus during feeding


The granule secretion process in Argas (Persicargas) arboreus salivary gland alveoli during feeding is described. Cells within an alveolus are not synchronized with respect to secretion. The secretory process is probably under neural control. In type II alveoli, large granules are released by apocrine secretion and small granules by merocrine secretion. Apocrine secretion is divided into three phases for descriptive purposes: (1) crawling of the tick on the host initiates formation of an intracellular membrane system connected to both the apical cell membrane and the membrane surrounding the granule, (2) breakdown of this membrane system releases granule contents and cytoplasm into the alveolar lumen and the salivary duct, and (3) spent secretory cells undergo a reduction in size. This granule secretion process has a significant adaptive value to the rapid repeated feeding of argasid ticks. Pharmacologically active substances are synthesized by secretory cells between feedings and are stored in the cell as granules isolated by a limiting membrane. The process is initiated by the presence of the host. It is rapid; not all of the secretory cells secrete during a single feeding and those that do remain intact enough for synthesis of new granules are used for repeated feedings. © 1981 Springer-Verlag.

Publication Title

Zeitschrift für Parasitenkunde Parasitology Research