Wallerian degeneration of the myelinated nerves of cat iris after denervation of the ophthalmic division of the trigeminal nerve: an electron microscopic study

Saari, Mohd Yusof; Kiviniemi, Pekka; Johansson, Gunnar; Huhtala, Antero

doi:10.1016/0014-4835(73)90179-6

Cited by 16 publications

(4 citation statements)

References 8 publications

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“…Sensory and autonomic fibres are not readily distinguished in the eye and there may be species differences, but the current consensus of opinion is that autonomic fibres are non-myelinated and that the myelinated fibres are all sensory [Saari, 1971;Huhtala, Johansson and Saari, 1975]. The myelinated fibres are all believed to be derived from the ophthalmic branch of the trigeminal nerve [Saari, Kiviniemi, Johansson and Huhtala, 1973;Huhtala, 1976] and our observations of degenerating myelinated bundles in iris-ciliary body tissue 6 days after coagulation of the Vth nerve are in accordance with this.…”

Section: Discussionsupporting

confidence: 77%

Axon Reflex in Ocular Injury: Sensory Mediation of the Response of the Rabbit Eye to Laser Irradiation of the Iris

Butler¹,

Unger²,

Cole³

1980

Exp Physiol

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Laser irradiation of the rabbit iris produces an injury response consisting of prolonged miosis, uveal vasodilation and a transient rise of intraocular pressure (IOP) accompanied by a breakdown of the blood-aqueous barrier. This response has hitherto been attributed partly to prostaglandin (PG) mediation and partly to mediation by a non-cholinergic nervous pathway thought to be sensory in function. Responses of the rabbit eye to laser irritation were examined at specified intervals after diathermic coagulation of the epigasserian nerve tract. Both the intensity of the pupillary constriction and the increase in IOP were almost unaltered at 90 minutes but progressively decreased until at 4 days there was essentially no response to high energy laser irradiation in the denervated eye. It was evident that manifestation of the response is largely dependent upon the presence of intact and functional sensory nerves, and it is proposed that endogenous PGs exert some, if not all of their effects via sensory nerve endings. It is suggested that those terminals which are directly stimulated, whether by laser irradiation or by PGs formed during the injury, release some mediator to cause pupillary constriction. From these terminals impulses pass orthodromically and antidromically by axon reflex to release further mediator from terminals in the region of the ciliary vessels or the major arterial circle. In this way the response is propagated and augmented.The response of the rabbit eye to injury consists of a miosis, anterior uveal vasodilation, a rise in the intraocular pressure (IOP) and a breakdown of the blood-aqueous barrier, leading to a rapid infiltration of plasma protein into the aqueous humour. To some extent, the mechanism would seem to depend upon the nature of the stimulus. The response to mechanical trauma, e.g. scratching the iris, appears to be mediated mainly by prostaglandins (PG) whereas that to chemical irritation involves a non-cholinergic nervous component believed to be identical to that with sensory function [

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Section: Discussionsupporting

confidence: 77%

Axon Reflex in Ocular Injury: Sensory Mediation of the Response of the Rabbit Eye to Laser Irradiation of the Iris

Butler¹,

Unger²,

Cole³

1980

Exp Physiol

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“…The autonomic ground plexus of the iris consists of a network of Schwann cells which supports bundles of non-myelinated axons [Richardson, 1964]. Electron microscopical studies have shown that in the cat iris the sympathetic and parasympathetic nerves are non-myelinated [Geltzer, 1969] and the myelina ted nerves are sensory [Saari et al, 1973].In this study we report ultrastructural changes in the non-myelinated nerves of the cat iris after denervation of the ophthalmic division of the trigeminal nerve. …”

mentioning

confidence: 72%

“…The ophthalmic division of the left trigeminal nerve was sectioned immediately peripheral to the Gasserian ganglion by electrocoagulation. The selective stereotactic method, described in more detail previously [Saari et at., 1973], was used. The contralateral eye served as control.…”

Section: Methodsmentioning

confidence: 99%

Observations on the Nerves of the Cat Iris after Denervation of the Ophthalmic Division of the Trigeminal Nerve

Johansson¹,

Huhtala²,

Saari³

1975

Ophthalmic Res

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The ophthalmic division of the trigeminal nerve was denervated stereotactically by electrocoagulation. Damage to the third nerve was avoided. Four days after denervation the homolateral iris was studied electron microscopically. There was Wallerian degeneration in the myelinated and also in part of the non-myelinated nerves of the iris. The ultrastructure of the iris nerves in the contralateral eye was normal. It is suggested that denervation of the ophthalmic division of the trigeminal nerve had caused interruption of the sympathetic nerves accompanying the trigeminal sensory nerves, and that the degenerated non-myelinated nerves of the iris are sympathetic in origin.

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“…The myelinated nerve fibres of the iris in mammals are considered to be sensory in character [ K r a p p , 1962;Saari, 1972, 1974: Saari and J ohansson, 1973Saari et «/., 1973c|. The mvelinated nerve fibres enter the pig iris along the long posterior ciliary nerve accom panying the long posterior ciliary artery [Saari, 19711)].…”

Section: Discussionmentioning

confidence: 99%

Organization of the myelinated nerve fibres in the iris of the White Leghorn hen

Saari¹,

Johansson²,

Huhtala³

1974

Cells Tissues Organs

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Wallerian degeneration of the myelinated nerves of cat iris after denervation of the ophthalmic division of the trigeminal nerve: an electron microscopic study

Cited by 16 publications

References 8 publications

Axon Reflex in Ocular Injury: Sensory Mediation of the Response of the Rabbit Eye to Laser Irradiation of the Iris

Axon Reflex in Ocular Injury: Sensory Mediation of the Response of the Rabbit Eye to Laser Irradiation of the Iris

Observations on the Nerves of the Cat Iris after Denervation of the Ophthalmic Division of the Trigeminal Nerve

Organization of the myelinated nerve fibres in the iris of the White Leghorn hen

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