Abstract
Purpose:
In ARVO 2009, we showed that these ducts bind the common C-terminal pentapeptide of both Gastrin and Cholecystokinin, indicating that lacrimal ducts bind one or both of them. This abstract reports that they bind gastrin. The possibility that they also bind cholecystokinin has not yet been studied.
Methods:
One exorbital lacrimal gland was excised from four female adult rats and fixed in buffered formalin. Immunohistochemistry was performed using a rabbit polyclonal antibody against the gastrin receptor, CCKBR. This demonstrated reactivity against rat tissues. A 1:500 dilution in phosphate buffered saline, pH 7.4 with 1% bovine serum albumin and 0.025% sodium azide, was made.The antibody was by Alamone Labs in Jerusalem. The positive control was the rat stomach whose HCl producing parietal cells were stained. The negative control omitted the primary antibody.
Results:
In all specimens essentially all nuclei of the intercalated, intra- and interlobular, and collecting ducts were strongly positive. Their cytoplasm was negative. The nuclei and cytoplasms of acinar and myoepithelial cells were negative. The lumens of some of the larger ducts had nuclear and cytoplasmic debris originating from ductal cytoplasmic blebs and the turnover of duct nuclei. This material enters the tears and passes through the nasolacrimal ducts to mix with nasopharyngeal secretions to enter the alimentary tract.
Conclusions:
The duct nuclei of rat exorbital lacrimal glands contain the specific receptor for gastrin. Just as gastrin affects gastric secretion might it affect how the llacrimal ducts modify the acinar secretions they receive?
Keywords: 576 lacrimal gland •
554 immunohistochemistry