Peptidergic Innervation of the Rat Cornea

Jones, Mark; Marfurt, Carl F.

doi:10.1006/exer.1997.0446

Cited by 101 publications

(77 citation statements)

References 75 publications

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“…Elles représenteraient, chez les rongeurs et le chat, environ 10 % des fibres innervant la cornée, mais leur densité serait très faible dans la cornée de primate, y compris celle de l'homme. Les fibres parasympathiques, provenant du ganglion ciliaire, expriment le vasoactive intestinal peptide (VIP), le NPY, la galanine et la Metenképhaline [5,13]. Par des techniques de traçage neuronal, il a été établi que ces fibres parasympathiques sont présentes dans la cornée de rat et de chat.…”

Section: Innervation Cornéenne : Anatomie Et Physiologieunclassified

La douleur oculaire chronique : mieux la comprendre pour mieux la traiter

Goazigo¹,

Labbé²,

Baudouin³

et al. 2017

Med Sci (Paris)

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> La sècheresse oculaire est un des premiers motifs de consultation en ophtalmologie. Sa prévalence varie de 5 à 35 % chez des sujets âgés de plus de 50 ans. Cette pathologie du segment antérieur de l'oeil est caractérisée par des sensations de douleur variables dans leurs intensités, allant du simple inconfort à une douleur oculaire prononcée. Les douleurs oculaires sont très invalidantes et très difficiles à traiter, et leurs mécanismes physiopathologiques demeurent mal connus de nos jours. Ce constat impose un approfondissement de nos connaissances fondamentales sur l'anatomie du système nociceptif cornéen et sur les mécanismes cellulaires impliqués dans l'initiation et la chronicisation de la douleur oculaire. Cette revue présente, dans une première partie, l'anatomie de l'innervation cornéenne et les différentes classes de récepteurs sensitifs cornéens. La seconde partie fait un état des lieux des données précliniques et cliniques portant sur les mécanismes inflammatoires mis en jeu dans cette pathologie. Enfin la dernière partie de cette revue décrit les différents dispositifs actuellement utilisés pour évaluer la douleur et l'inflammation oculaire en clinique humaine. < sulaire présent ou potentiel, ou décrite en terme d'un tel dommage ». Les pathologies de la surface oculaire représentent l'un des principaux motifs de consultation pour douleurs oculaires en ophtalmologie. La douleur oculaire est le plus important signe cardinal d'alerte en réaction à une inflammation ou à un traumatisme des structures du segment antérieur de l'oeil comme la cornée, la conjonctive, la sclère 2 et les structures uvéales. La douleur oculaire chronique est tout à fait remarquable par la variabilité de l'intensité qu'elle peut générer, allant du simple inconfort oculaire à une douleur intense voire insupportable. La douleur chronique consé-cutive à une pathologie de la surface oculaire affecte la qualité de la vie : près de 60 % des patients se déclarent gênés dans leurs activités quotidiennes [1]. En outre, 80 % des patients qui souffrent de douleur oculaire ne l'estiment pas suffisamment prise en considération tant par leur entourage que par leurs médecins. Les douleurs chroniques oculaires sont malheureusement parmi les plus difficiles à traiter et leurs mécanismes physiopathologiques, de nature neurogène et/ou inflammatoire, demeurent de nos jours très mal connus [2,3]. Innervation cornéenne : anatomie et physiologieLa sensibilité somatique de la face, incluant les cavités buccale et nasales, et des méninges, est assurée par les trois branches du ganglion trigéminal : ophtalmique (V1), maxillaire (V2) et mandibulaire (V3). Le nerf ophtalmique V1 se divise en trois branches sensitives : les 2 Enveloppe fibreuse externe du globe oculaire.

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Section: Innervation Cornéenne : Anatomie Et Physiologieunclassified

La douleur oculaire chronique : mieux la comprendre pour mieux la traiter

Goazigo¹,

Labbé²,

Baudouin³

et al. 2017

Med Sci (Paris)

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“…Several biological functions have been attributed to corneal neuropeptides; these include sensory perception and involvement in corneal epithelial regeneration. Additionally, the detection of neuropeptides adjacent to the limbal vasculature has led to the suggestion that they may be vasomodulators (Jones and Marfurt, 1998). The vasostatins represent candidate CgA-derived neuropeptides that may impact the local vasculature (Aardal and Helle, 1992).…”

Section: Discussionmentioning

confidence: 99%

“…Cornea sympathetic innervation contains the classical neurotransmitters noradrenaline and serotonin, and neuropeptide Y (NPY) (Marfurt, 2000). Corneal parasympathetic innervation, which appears limited, contains vasoactive intestinal polypeptide (VIP), met-enkephalin, and NPY (Jones and Marfurt, 1998). Additional neuropeptides and pan-neuronal markers detected include cholecystokinin (CCK) (Palkama et al, 1986), vasopressin (Too et al, 1989), brain natriuretic peptide (Yamamoto et al, 1991), neurotensin (Tinsley et al, 1988), neurone-specific enolase (NSE) (Ueda et al, 1989), and protein gene product (PGP) 9.5 (Marfurt et al, 1993) have been detected in corneal nerves.…”

Section: Introductionmentioning

confidence: 96%

Localisation of WE‐14 immunoreactivity in the developing mouse limbo‐corneal nerve net

Curry¹,

Brockbank²,

McCollum³

et al. 2003

Microscopy Res & Technique

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WE-14 is generated in subpopulations of chromogranin A immunopositive endocrine cells and neurons including those innervating the anterior uvea. This study investigated WE-14 in intact sclero-limbo-corneal tissue from embryonic (E17), neonatal (N0-N16), and adult mice using immunocytochemistry and confocal scanning laser microscopy. Weak WE-14 immunostaining was observed at birth in nerve fibre tracts entering the corneal mid-stroma from the limbo-scleral junction. Immunopositive fibre tracts were evident throughout the cornea at N3; by N5 the mid-stromal plexus had begun to generate fibre populations extending toward the developing corneal epithelium, and some varicose fibres terminated amongst the developing epithelium. Immunostaining was evident at N7 in the developing limbo-scleral nerve net and some fibres exhibited a close association with unidentified vascular elements. By N11 and in subsequent neonates, the cornea had developed a distinct stratified nerve net composed of thick mid-stromal and thinner upper stromal nerve fibre bundles; both possessed populations of varicose WE-14 immunopositive fibres. In the adult, a sub-epithelial network of varicose WE-14 immunopositive fibres were evident at the limbo-scleral junction. Some fibres exhibited a close association with unidentified vascular elements, while others extended into the upper peripheral corneal stroma. WE-14 was evident in leashes throughout the basal corneal epithelium and generated fibres ramifying between the stratified epithelium with some fibres terminating amongst the outermost corneal epithelia. This study has demonstrated that WE-14 was evident in the limbo-corneal nerve net at birth and that its detection parallels corneal development to adulthood, where WE-14 is evident in a subpopulation of nerve fibres.

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“…8,32,33 With respect to opioid peptides, gene expression for preproenkephalin (the precursor of [Met 5 ]-and [Leu 5 ]-enkephalin) has been detected in cornea, limbus, and conjunctiva, 34 and either or both peptides have been reported in tears and the conjunctiva, corneal epithelium, corneal and conjunctival stroma, Harderian gland or lacrimal gland. [34][35][36][37][38][39][40][41][42] At least one opioid receptor, the d opioid receptor, has been reported in monkey cornea and limbus. 43 In the case of the lacrimal gland, enkephalins and enkephalin analogues have been reported to inhibit secretion.…”

Section: Discussionmentioning

confidence: 99%

Spontaneous Episodic Decreased Tear Secretion in Rats Is Related to Opioidergic Signaling Pathways

Zagon¹,

Campbell²,

Sassani

et al. 2012

Invest. Ophthalmol. Vis. Sci.

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PURPOSE.To elucidate the factors in tear production, this study examined the role of endogenous opioids and opioid receptors in spontaneous episodic reduced tear volume. METHODS.A model of spontaneous episodic decreases in the quantity of tears was characterized in otherwise normal Sprague-Dawley rats using Schirmer's test. A single eye drop of 10 -5 M naltrexone (NTX), 10 -5 M [Met 5 ]-enkephalin, or sterile vehicle was administered to one eye. Tear secretion, corneal sensitivity, and corneal morphology were examined in both eyes. RESULTS.At any given time period, otherwise normal rats were found to have Schirmer test scores with a bimodal distribution (6.5 mm or less, or 7.0 mm or greater). Decreased tear production was detected in male and female rats aged 4 to 24 weeks at least once per animal. The episodes of reduced tear volume ranged from 1 to 7 days. No changes in corneal sensitivity or corneal morphology were observed in any rat. One drop of NTX given to rats with a decrease in tear volume raised levels of tears to scores of 7.0 mm or greater within 1 hour, and increased tear production persisted for at least 48 hours. NTX had no effect on rats with Schirmer scores of 7.0 mm or higher. Topical application of [Met 5 ]-enkephalin depressed tear secretion from baseline scores of 9.8 6 0.6 mm to as low as 4.5 6 0.7 mm.CONCLUSIONS. Normal rats experience fluctuations in tear production that can be modulated by opioidergic signaling pathways. (Invest Ophthalmol Vis Sci. 2012;53:3234-3240) DOI:10.1167/iovs.11-9051 T ears are important to the health of the cornea, and function in lubrication, nourishment for the cornea, gas exchange, removal of debris from the corneal surface, and prevention of bacterial and viral infections.1 In addition to maintenance of the surface homeostatic environment, the precorneal tear film serves to maintain an optically uniform corneal surface essential for normal vision. The pathophysiology of reduced tear film may involve tear production deficiency that can increase corneal inflammation, impair vision, and even have complications leading to blindness.2-4 Alternatively, changes in environmental factors such as temperature and humidity may lead to transient increases in tear film evaporation. 5,6 Although the components of tears have been identified and characterized, 2,5-10 the regulation of tear production is multifaceted involving not only physiology but environmental stimuli. 6 Previous studies in our laboratory have established a relationship between opioidergic systems (i.e., endogenous opioid peptides and opioid receptors) and tear production in diabetic rats.11 A decrease in tear volume in animals with type 1 diabetes (T1D) was reversed within 1 hour of administration following the topical administration of the opioid antagonist naltrexone hydrochloride (NTX); the effect persisted for up to 3 days. During these studies we noted that normal rats occasionally had a marked reduction in Schirmer test scores, suggesting that normal tear production may fluctuate. The present inv...

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Peptidergic Innervation of the Rat Cornea

Cited by 101 publications

References 75 publications

La douleur oculaire chronique : mieux la comprendre pour mieux la traiter

La douleur oculaire chronique : mieux la comprendre pour mieux la traiter

Localisation of WE‐14 immunoreactivity in the developing mouse limbo‐corneal nerve net

Spontaneous Episodic Decreased Tear Secretion in Rats Is Related to Opioidergic Signaling Pathways

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Peptidergic Innervation of the Rat Cornea

Cited by 101 publications

References 75 publications

La douleur oculaire chronique : mieux la comprendre pour mieux la traiter

La douleur oculaire chronique : mieux la comprendre pour mieux la traiter

Localisation of WE‐14 immunoreactivity in the developing mouse limbo‐corneal nerve net

Spontaneous Episodic Decreased Tear Secretion in Rats Is Related to Opioidergic Signaling Pathways

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La douleur oculaire chronique : mieux la comprendre pour mieux la traiter

La douleur oculaire chronique : mieux la comprendre pour mieux la traiter