Motilin Receptor Expression Found in the Human Main and Accessory Lacrimal Glands.

Introduction: In this study, we investigated the presence of motilin receptors (MR) in adnexal tissue including the human main lacrimal gland.Method: 17 adnexal human specimens comprising of 11 isolated human main lacrimal gland specimens, four full-thickness human eyelid excisions and two exenterations containing full-thickness eyelid and portions of the main lacrimal gland were immunolabelled with a rabbit polyclonal human MR antibody.Results: Our results demonstrated that all main lacrimal gland specimens (13/13, 100%) were positive for MR expression with a predominance (10/13 (77%) of grade 1+ punctate distribution. Motilin receptors were not found in eccrine glands, cutaneous sebaceous glands, glands of Zeis or glands of Moll (0/6, 0%). We also confirmed MR expression in the accessory lacrimal gland tissue.Conclusion: In summary, we discovered the MR receptor in the lacrimal and accessory lacrimal gland - the significance of which, in the lacrimal gland, remains unclear - but motilin may play a role in the muscarinic control of aqueous tear secretion.