Figure 3
Immunostaining of ChAT in Ixodes salivary gland (SG). Whole-mount immunohistochemistry of I. ricinus (A,B) and I. scapularis (C) unfed female SG. Note that cholinergic axons (green) run along the main salivary duct (arrows) and terminate exclusively within the acini type I (arrowheads). Roman numbers II and III indicate type II and III acini located more distally from the main salivary duct (MD). (D) Detailed view of single type I acinus, highlighting its arborized cholinergic axon terminals (green, arrows). Solid lines indicate acinus boundaries. (E–G) Transmission electron microscopy (TEM) image showing the axons containing electron-dense vesicles (arrows in G) within the type I acinus in SG of five days fed Ixodes female. Insets in E and F are magnified in (F,G) respectively. Note that axons were found in contact with basolateral infoldings (white squares in G) of acinar lamellate cells. (H) TEM image showing immunogold ChAT antibody labeling of the axon within the type I acinus in SG of unfed female. The black arrowheads indicate the 6 nm gold nanoparticles within the axoplasm (inset), while the white arrowheads show the axolemma. Blue in C and D is DAPI staining for nuclei. Scale bar is 50 μm in (A–C), 10 μm in (D, E), 1 μm in (F), 500 nm in (G), and 100 nm in (H).
