The Role of Gap Junctions in Lacrimal Acinar Cells: The Formation of Tears

Water movement in the lacrimal gland is a consequence of ion channel and transporter activity. The production of tears is a consequence of acetylcholine (Ach) stimulation of acinar and duct cells, which produce a transepithelial flux of ions resulting in fluid movement. Ach acts through phospholipase C via Gq/11 and subsequently results in elevation of intracellular IP3 and DAG. The former raises intracellular calcium while the latter activates many PKC isoforms (Walcott, 1998; Dartt et al., 1998). In lacrimal gland K+, chloride and cation channels are activated by elevated intracellular calcium (Marty et al., 1984; Begenisich and Melvin, 1998).