Neural regulation of lacrimal gland secretory processes: Relevance in dry eye diseases

Abstract

The lacrimal gland is the major contributor to the aqueous layer of the tear film which consists of water, electrolytes and proteins. The amount and composition of this layer is critical for the health, maintenance, and protection of the cells of the cornea and conjunctiva (the ocular surface). Small changes in the concentration of tear electrolytes have been correlated with dry eye syndrome. While the mechanisms of secretion of water, electrolytes and proteins from the lacrimal gland differ, all three are under tight neural control. This allows for a rapid response to meet the needs of the cells of the ocular surface in response to environmental conditions. The neural response consists of the activation of the afferent sensory nerves in the cornea and conjunctiva to stimulate efferent parasympathetic and sympathetic nerves that innervate the lacrimal gland. Neurotransmitters are released from the stimulated parasympathetic and sympathetic nerves that cause secretion of water, electrolytes, and proteins from the lacrimal gland and onto the ocular surface. This review focuses on the neural regulation of lacrimal gland secretion under normal and dry eye conditions.

Histological, histochemical and ultrastructural studies on Harderian and lacrimal glands of the Capercaillie (Tetrao urogallus majorL.)

“…In birds, numerous studies concentrated on the HG [2,29,31] and just a few on the LG [7,10,14]. In our study, the HG of the Capercaillies was located ventromedially, near the inter-orbital septum of the orbit, between the medial straight muscle, pyramidal third eyelid muscle and ventral oblique muscle.…”

Histological, histochemical and fine structure studies of the lacrimal gland and superficial gland of the third eyelid and their significance on the proper function of the eyeball in alpaca (Vicugna pacos)

“…Lymphoid cells which were found in the LG are very important in the creation of local immunity in the eye and, due to their ability to secrete immunoglobulins, are also the important protecting factor within the nasopharynx. The activated plasma cells are the source of plasma immunoglobulins protecting the sensitive mucosa and the ocular surface of the eye against diseases, including many upper respiratory diseases in ruminants [7,31,38]. Based on Franklin et al [15] study, the human LG plasma cells are predominantly IgA type and are responsible for the local production of the IgA that is the prevalent immunoglobulin in tears.…”

Adult Gland Derived Stem Cells (Gdscs); Potentials, Hurdles and Expectations

“…Approximately 80%, of the gland are the acinar cells, which secrete electrolytes, water, and proteins [96].…”