Abstract
Abstract: :
Purpose: To determine the presence and distribution in the human lacrimal gland of the neuropeptide, somatostatin. Methods: Orbital lobe tissue was removed from one lacrimal gland of each of four embalmed cadavers in the medical school gross anatomy laboratory. Subjects were elderly individuals of both sexes. Formalin-fixed sections were boiled in citrate buffer, pH 6 for 10 minutes. Endogenous peroxidase was blocked by 3% H2O2. Normal goat serum was the protein block to reduce nonspecific binding. The primary antibody was very dilute rabbit polyclonal anti-human somatostatin tetradecapeptide (DAKO Corp.). As the negative control, corresponding sections were treated with the primary antibody following its absorption with somatostatin having a 3-14 disulfide bridge. The link was biotinylated anti-immunoglobulins and the label horseradish peroxidase-labeled streptavidin. DAB was the chromogen and Mayer's hematoxylin the counterstain. Results: There was patchy distribution and intensity of somatostatin-like immunoreactivity (SLIR). Whether these findings are inherent or due to the preceding embalming is unknown. Nevertheless, various areas exhibited SLIR ranging from apparently none to appreciable. Where it was present, usually all cells of an acinus appeared to contain the neuropeptide throughout their cytoplasm. However, at times, only some did. SLIR was also present throughout the cytoplasm of the epithelial cells of the duct system. Nonspecific staining was common in the control slides but its intensity was usually less than in the primary sections. Conclusions: Somatostatin-like immunoreactivity exists both in the acinar cells and the epithelial cells of the duct system. It is likely that the use of embalmed tissues has affected its appearance both in the primary and control sections. Therefore, similar studies on routine autopsy specimens would be preferable. The role this inhibitory neuropeptide might play in normal human lacrimal physiology, and perhaps in disorders having a diminution of tear volume, remains to be elucidated.
Keywords: 452 lacrimal gland • 474 microscopy: light/fluorescence/immunohistochemistry • 488 neuropeptides