Immunohistochemical identification of galanin and leucin-enkephalin in the porcine lacrimal gland.

The presence and distribution of galanin (GAL) and leucine-enkephalin (LEU-ENK) in the pig lacrimal gland was investigated using immunohistochemical techniques. Lacrimal gland segments obtained from the abattoir were fixed in paraformaldehyde-picric acid solution, cut into 40-50 microns thick sections and processed for immunohistochemistry using polyclonal antisera against GAL and LEU-ENK. GAL- and LEU-ENK-immunoreactive intrinsic multipolar neurons were observed in the interacinar and interlobular areas of the pig lacrimal gland. From these regions these intrinsic neurons send branches to the acinar and other tissues of the gland. Immunoreactivity was confined solely to the neural elements. These two potent biologically active neuropeptides may play important roles in the regulation of lacrimal fluid secretion.