Evidence of a myoepithelial cell in tick salivary glands

Receptors for the neuropeptides, myoinhibitory peptide and SIFamide, in control of the salivary glands of the blacklegged tick Ixodes scapularis

“…The immunohistochemistry of SIFa-R in this study, along with the ultrastructure of SG acini described in previous studies (Binnington, 1978; Coons et al, 1994; Coons and Roshdy, 1973; Fawcett et al, 1986; Krolak et al, 1982; Meredith and Kaufman, 1973; Roshdy and Coons, 1975), suggests that there are at least three different target cell types that exhibit different functions in the control of the SGs. Although previous descriptions of these cell types and the number of the basally located acini cells have varied depending on the tick species, feeding phases, and methods of investigation, three commonly described cell types were identified in the basal region of the acini, specifically myoepithelial cells, basal granular cells, and neck cells.…”

“…Although previous descriptions of these cell types and the number of the basally located acini cells have varied depending on the tick species, feeding phases, and methods of investigation, three commonly described cell types were identified in the basal region of the acini, specifically myoepithelial cells, basal granular cells, and neck cells. The myoepithelial cell (Coons et al, 1994), also known as the Cap cell (Krolak et al, 1982; Meredith and Kaufman, 1973) or adluminal cell (Fawcett et al, 1986; Sauer et al, 1995), has narrow cellular branches lining the acini luminal surface and extends to the upper lip region of the acinar valve. The myoepithelial cell was proposed to function in the contraction of the acini (Coons et al, 1994; Coons and Roshdy, 1973), but also may function in the control of the acinar valve.…”

Orchestration of salivary secretion mediated by two different dopamine receptors in the blacklegged tickIxodes scapularis

“…These were difficult to distinguish when the acini were fully expanded because rapid size reduction could be partly caused by release of high internal pressure in the absence of the contraction. Summing up the observations, two components of salivary secretion are epithelial cell fluid transport for water-solute influx and myoepithelial cell contraction (Coons et al, 1994) for generating internal pressure with valve opening allowing saliva efflux through the acinar duct. The full salivary secretion rate required both processes based on the experiment using pharmacological tools ( Fig.…”

“…5B). Typical pumping is shown by rapid reduction of the acini size that appeared, such as a squeezing muscular contraction of the acini (supplementary material Movie 2) (Coons et al, 1994). In some cases, slow reduction in size occurred over a relatively long duration.…”

The Essential Role of Tick Salivary Glands and Saliva in Tick Feeding and Pathogen Transmission

“…In type II and III acini, in addition to various agranular cell types (such as epithelial, adlumenal, ablumenal interstitial, and neck cells), 7–9 various glandular cells (divided into the a-f types depending on tick species), enclosing the secretory granules have generally been recognized (Fawcett et al, 1986; Sonenshine, 1991). The single adlumenal cell, also called the Cap or myoepithelial cell (Meredith and Kaufman, 1973; Krolak et al, 1982), lines the luminal surface of the type II and III acini in web-like fashion, and its contractions facilitate expulsion of the acinar contents into the connecting ducts during tick feeding (Krolak et al, 1982; Coons et al, 1994; Šimo et al, 2014b). During feeding of Ixodid females, the majority of the acinar cells of both type II and III acini undergo marked hypertrophy, resulting in overall increase in the mass of the SG (Binnington, 1978; Fawcett et al, 1986; Šimo et al, 2013).…”