Stimulation of goblet cell mucous secretion by activation of nerves in rat conjunctiva

Abstract

An epithelial debridement wound, as a stimulus to the cornea, causes conjunctival goblet cell mucous secretion in that eye. To determine if this stimulation of secretion is neurally mediated, rats were anesthetized and the local anesthetic lidocaine (1%) or buffer alone was administered topically and/or subconjunctivally for 15 min. A corneal epithelial debridement wound was made in one eye. The contralateral eye served as the control. After 5-120 min, animals were sacrificed and inferior bulbar conjunctival buttons removed. Mucus in the goblet cells was stained with Alcian blue and periodic acid-Schiff's reagent to indicate mucin-containing goblet cells. The number of mucin-containing goblet cells/0.16 mm2 was determined by light microscopy; a decrease in number indicated an increase in mucous secretion. Stimulation by corneal wounding induced goblet cell mucous secretion in that eye. Secretion was observed as rapidly as 5 min after stimulus and for as long as 120 min. Topical application of lidocaine, subconjunctival injection of lidocaine, or a combination of both inhibited wound-induced stimulation of mucous secretion. We conclude that conjunctival goblet cell mucous secretion can be neurally mediated and could serve as an immediate response to protect the ocular surface.

Effect of Proparacaine in a Mouse Model of Allergic Rhinitis

“…This finding was in concordance with a recent study which found that a lidocaine analog significantly inhibited OVAinduced mucus secretion in mice [18]. A different study found that topical application of lidocaine inhibited mucous secretion [19]. Our finding further supports previous findings in which lidocaine suppressed goblet cells.…”

Regulation of Conjunctival Goblet Cell Secretion by Ca2+and Protein Kinase C

“…It is worth noting that the number of mucin-containing goblet cells varies considerably between individuals and areas of the conjunctiva. Thus, to minimize variability, the same area of the conjunctiva was removed each time and for each experiment a basal and all concentrations of agonist were evaluated from each animal (Kessler et al, 1995;Dartt et al, 1996). Therefore, this limits the number of concentrations of agonists and antagonists that can be used.…”

“…Immediately after the rats were killed, the globes of both eyes were removed with the lids intact as previously described (Kessler et al, 1995). The globe was ®xed for 4 hr at 48C in 4 % formaldehyde in phosphate buffered saline (PBS, which contained 145 mM NaCl, 7 .…”

“…Upon stimulation, the secretory granules fuse with one another and with the apical membrane releasing mucins and other secretory proteins onto the ocular surface (Forstner, 1995). Previously we showed that conjunctival goblet cell mucin secretion is under neural control as activation of afferent sensory nerves in the cornea stimulates mucin secretion (Kessler et al, 1995;Dartt et al, 1996). This neural re¯ex is mediated either by the parasympathetic and sympathetic nerves that surround the goblet cells or by antidromic stimulation of the sensory nerves in the conjunctiva and collateral sensory nerves from the cornea (Kessler et al, 1995;Dartt et al, 1996).…”

“…Previously we showed that conjunctival goblet cell mucin secretion is under neural control as activation of afferent sensory nerves in the cornea stimulates mucin secretion (Kessler et al, 1995;Dartt et al, 1996). This neural re¯ex is mediated either by the parasympathetic and sympathetic nerves that surround the goblet cells or by antidromic stimulation of the sensory nerves in the conjunctiva and collateral sensory nerves from the cornea (Kessler et al, 1995;Dartt et al, 1996). Exogenous addition of the parasympathetic agonist carbachol or the parasympathetic neuropeptide VIP stimulated conjunctival goblet cell secretion (Dartt et al, 1996).…”