Localization of nerves adjacent to goblet cells in rat conjunctiva

Abstract

Neural stimulation of the cornea induces conjunctival goblet cell mucous secretion. Immunofluorescence microscopy was used to determine if nerves are present near conjunctival goblet cells and what types of nerves are present. In euthanized rats, the local anesthetic lidocaine (1%) was placed topically on the ocular surface for 10 min to prevent goblet cell mucous secretion. The ocular surface tissues were removed and either fixed in formaldehyde and then frozen, or frozen first and then post-fixed in formaldehyde. Tissue was sectioned and nerves localized by indirect immunofluorescence microscopy, using antibodies to synaptophysin (indicates nerve, independent of type), vasoactive intestinal peptide (VIP, indicates parasympathetic nerves), tyrosine hydroxylase (TH, indicates sympathetic nerves), dopamine beta-hydroxylase (DBH, indicates sympathetic nerves), phenylethanolamine-N-methyltransferase (PNMT, indicates sympathetic nerves), and calcitonin gene-related peptide (CGRP, indicates sensory nerves). Goblet cells were identified by phase-contrast microscopy. Synpatophysin-containing nerves were present in the basolateral region of conjunctival goblet cells clusters. Nerve fibers immunoreactive to VIP were found in the conjunctiva along the epithelial-stromal junction and around the basolateral aspect of goblet cell clusters. Nerve fibers immunoreactive to TH and DBH were detected surrounding goblet cells and in the conjunctival stroma. Nerve fibers immunoreactive to CGRP were detected in the epithelium and at the epithelial stromal junction, but were not localized near goblet cell clusters. CGRP-containing nerve fibers were also detected in the conjunctival stroma under the epithelium. We conclude that efferent parasympathetic and sympathetic, but not afferent sensory, nerves appear to be located adjacent to conjunctival goblet cell clusters. Activation of efferent parasympathetic and sympathetic nerves could directly stimulate conjunctival goblet cell mucous secretion. Antidromic activation of afferent sensory nerves releasing neurotransmitters could stimulate goblet cell secretion by a paracrine mechanism.

Vasoactive Intestinal Polypeptide (VIP) Innervation of the Human Eyelid Glands

“…Likewise, an intercellular communication could be transmitted via gap junctions from directly innervated cells of the basal cell layer, as demonstrated experimentally in the corneal epithelium of rabbits (Williams and Watsky, 1997). In contrast to the present findings, other authors (Dartt et al, 1995(Dartt et al, , 1996 have described VIPimmunoreactive, nerve-like structures associated with goblet cells of the bulbar conjunctiva of the rat, however, no electron microscopic evidence was given. Conversely the possibility cannot be excluded that differences between two species exist.…”

Changes in Corneal Sensation and Ocular Surface in Patients With Asymmetrical Keratoconus

“…Our data suggest that decreased corneal sensation is associated with tear deficiency, abnormal impression cytologic results, and thinning of the cornea in KC. Dartt et al 22 showed that the nerves appear to be located around conjunctival goblet cells and could stimulate mucous secretion directly. Sensory neurotransmitters in the limbus or conjunctiva can be released antidromically by depolarization from activated sensory nerves in the central cornea in a process known as neurogenic irritation.…”

Herpes Simplex Virus 1 Reactivates from Autonomic Ciliary Ganglia Independently from Sensory Trigeminal Ganglia To Cause Recurrent Ocular Disease

“…HSV-1 and HSV-2 demonstrate neuronal specificity for A5ϩ and IB4ϩ neurons, respectively, regardless of the route of infection. One-half of the LAT-positive latent HSV-1 reservoir is found in A5ϩ neurons, and one-half of the LAT-positive latent HSV-2 reservoir is found in IB4ϩ neurons, in the TG after ocular infection or in the DRG after genital infection (5)(6)(7)(8)(9). Thus, different patterns of HSV-1 and HSV-2 recurrence cannot be adequately explained by preferential establishment of latency in different types of sensory neurons.…”

“…Sympathetic neurons of the superior cervical ganglia (SCG) and parasympathetic neurons in the ciliary ganglia (CG) innervate the conjunctival epithelium and stroma (6), and mixed autonomic neurons in the major pelvic ganglia (MPG) innervate the genitourinary tract. In both humans and animal models, HSV-1 and HSV-2 latent viral DNA has been detected in autonomic ganglia, including the SCG, CG, pterygopalatine ganglia (PTG), and MPG (also referred to as the paracervical ganglia) (7)(8)(9)(10)(11)(12).…”