Palisade Endings: Cholinergic Sensory Organs or Effector Organs?

Blumer, Roland; Konakci, Kadriye Zeynep; Pomikal, Christine; Wieczorek, Grazyna; Lukas, Julius-Robert; Streicher, Johannes

doi:10.1167/iovs.08-2748

Cited by 35 publications

(69 citation statements)

References 18 publications

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“…In later studies of other species, the same authors ascertained that the structures in question are pure cholinergic motor organs arising from axons that also supply the associated MIF. [27][28][29][30] They hence argued, in contrast to previous studies, 31 that surgical strabismus procedures should have no side effects with respect to eye-position signals. 30 Other studies, using central tracer injections in non-human primates, also support a motor function, but suggest that tendon endings and 'en grappe' terminals arise from separate neurons located around the periphery of the motor nuclei of EOMs.…”

Section: Myotendinous Nerve Endingsmentioning

confidence: 89%

“…[27][28][29][30] They hence argued, in contrast to previous studies, 31 that surgical strabismus procedures should have no side effects with respect to eye-position signals. 30 Other studies, using central tracer injections in non-human primates, also support a motor function, but suggest that tendon endings and 'en grappe' terminals arise from separate neurons located around the periphery of the motor nuclei of EOMs. 32,33 Even though it cannot be precluded that myotendinous nerve endings have a sensory function, 2,34 the notion that muscle spindles represents the only structures with proprioceptive potency seem to gain growing support.…”

Section: Myotendinous Nerve Endingsmentioning

confidence: 89%

“…While a small percentage of the nerve terminals make contact with contractile material and putative postsynaptic acetylcholine receptors in EOMs of some species, 30 attempts to confirm these findings in other species have failed. 50 Animal studies may hence not always be directly applicable as models for human oculomotor control.…”

Section: Discussionmentioning

confidence: 99%

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How does the structure of extraocular muscles and their nerves affect their function?

Bruenech

Haugen²

2014

Eye

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The sensory and motor control of human extraocular muscles (EOMs) have been subjected to considerable speculation in ophthalmic literature, often related to infranuclear structures such as the unique complement of muscle fibres and their associated sensory organs. The intrafusal fibres do not resemble their somatic counterparts and their peculiar morphology has raised questions about their proprioceptive capacity. No Golgi tendon organs have so far been observed and the myotendinous nerve endings, previously assumed to convey sensory information, have recently been argued to merely represent constituents of the efferent innervation serving the multiply innervated muscles fibres. These observations raise questions about the overall capacity to monitor the activity created by the generous efferent nerve supply observed in these muscles. Furthermore, the argued independent activity of muscular layers and compartments suggest that the required feedback must be highly structured and more specific than previously assumed. Yet, uncertainty about the source of such information remains. The purpose of this paper is to provide a short review of neuromuscular properties of human extraocular muscles. Their functional implications and the most reputable sources of proprioception will also be discussed. The promoted views are based on pertinent literature and previous research undertaken by the authors.

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Section: Myotendinous Nerve Endingsmentioning

confidence: 89%

Section: Myotendinous Nerve Endingsmentioning

confidence: 89%

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How does the structure of extraocular muscles and their nerves affect their function?

Bruenech

Haugen²

2014

Eye

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“…Investigation of molecular phenotypes revealed that palisade endings are cholinergic structures (Blumer et al, 2009), and tracing studies located their cell body in close proximity to oculomotor nuclei (Lienbacher et al, 2011a;Zimmermann et al, 2011). In addition, immunoreactivity of nicotinic acetylcholine receptors by ␣-bungarotoxin has shown that a substantial minority of palisade ending axons form sequential motor terminals along the muscle body before establishing tendinous terminations (Blumer et al, 2009).…”

Section: Review Of Zimmermann Et Almentioning

confidence: 99%

Proprioceptive Eye Position Signals Are Still Missing a Sensory Receptor

Rao¹,

Prevosto

2013

Journal of Neuroscience

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“…Observations of nerve terminals with efferent features have led some authorities to promote that these structures form part of the conventional motor innervations of the MIFs (Blumer et al, 2009). An alternative view is that the efferent innervations may tune the sensitivity of the receptor in a similar manner as the efferent innervations adjusting the intrafusal fibres in spindles.…”

Section: Sensory Receptorsmentioning

confidence: 99%

The Oculomotor Systems Ability to Adapt to Structural Changes Caused by the Process of Senescence: A Review

Bruenech

Haugen

Bak³

et al. 2012

Scand J Optom Vis Sci

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Age-related binocular vision anomalies are frequently encountered during clinical examination of mature patients. Observations of both concomitant and incomitant restrictions in eye motility indicate that all oculomotor system levels are implicated, from cortical neurons down to extraocular muscles. The system can make adaptations in response to changes induced by growth and ageing, which it does by monitoring and adjusting its own performance. This adaptive mechanism, which is important for maintaining motility, spatial orientation, and perceptual stability, seems to rely on extra-retinal information about eye position in relation to the head and trunk. Receptors in the extraocular muscles and the vestibular system, assumed to contribute to this type of information, also undergo age-related changes. This may compromise their ability to assist in the adaptive process and in potential calibrations of other neural systems. Furthermore, recent observations of a dual, common, final pathway and double insertions of distal extraocular muscles suggest that muscle and tendon receptors may facilitate other, still unresolved, functions in the visual system. Consequently, age-related changes in certain mechanoreceptors may have more severe implications for ocular motility and visual functions than previously assumed.This review aims to detail some of the most frequent neurogenic and myogenic age-related changes that take place in the human oculomotor system and relevant pre-motor structures. It will also address clinical implications of these changes and the potential adaptive mechanism they initiate.

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Palisade Endings: Cholinergic Sensory Organs or Effector Organs?

Abstract: The present study ascertained that palisade endings are cholinergic motor organs. Therefore, it was concluded that palisade endings are not candidates to provide eye-position signals.

Cited by 35 publications

References 18 publications

How does the structure of extraocular muscles and their nerves affect their function?

How does the structure of extraocular muscles and their nerves affect their function?

Proprioceptive Eye Position Signals Are Still Missing a Sensory Receptor

The Oculomotor Systems Ability to Adapt to Structural Changes Caused by the Process of Senescence: A Review

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