The vacuoles may reflect excretory function or
pinocytotic vesicles; in other molluscs, these are thought to be involved in glucose resorption (Taylor & Andrews 1987, Andrews 1988).
These cells were flattened with long branching cytoplasmic processes that contained, in many cases,
pinocytotic vesicles with areas of contacts in between.
Weiss and Enzinger (2) identified multiple endothelial structures on electron microscopy, including elaborate junctional attachments,
pinocytotic vesicles, investing basal lamina, and Weibel-Palade bodies.
Cytoplasm contained abundant mitochondria and
pinocytotic vesicles.
In addition, type II epithelial microvilli were missing or shortened, lamellar bodies were empty, chromatin was found at the periphery of nuclei, vascular endothelial cells were swollen and there were more
pinocytotic vesicles.
FSBM induces significantly lower morphological changes such as disintegration of microvilli, absence of granulated
pinocytotic vacuoles, etc in fingerling rainbow trouts (Yamamoto et al., 2010).
Hence, most promising drug delivery through brain capillaries is possible by augmentation of
pinocytotic vesicles.
The ultrastructure of fully developed lymphatic endothelium is characterized by the presence of many cisternae of Golgi complexes,
pinocytotic vesicles, vacuoles, cytoplasmic microfilaments and anchoring filaments, and the lack of basement membrane [52, 53].
Electron microscopy findings suggest tumour cells with well-defined basement membrane, scattered electron dense condensations in the plasma membrane, abundant glycogen, and
pinocytotic vesicles and cytoplasmic filaments [24].