Contractile Properties of Extraocular Muscle in Siamese Cat

Lennerstrand, Gunnar

doi:10.1111/j.1755-3768.1979.tb00534.x

Cited by 12 publications

(7 citation statements)

References 19 publications

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“…The contractile properties were the same in extraocular muscle of normally pigmented and albino guinea pig. This is in marked contrast to the conditions in the cat, where albino (Siamese) cats showed slower contraction and less fatigue resistance than normally pigmented cats (Lennerstrand 1979). The results of the present study speak strongly in favour of the idea that differences found between normal and Siamese cats depend on functional and not on genetic differences and that they are related to the lack of binocular vision in the Siamese cat.…”

Section: Discussioncontrasting

confidence: 87%

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Contractile properties and histochemistry of extraocular muscle in the pigmented and the albino guinea pig

Lennerstrand

1985

Acta Ophthalmologica

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The inferior oblique muscles of pigmented and albino guinea pigs were compared with respect to contractile and histochemical properties. No differences were found between the 2 kinds of animal in twitch and tetanic response or in fatigue properties. They also had the same fiber composition and fiber and capillary densities of their inferior obliques. These findings indicate that differences in eye muscle previously demonstrated and Siamese (albino) cats are related to the state of binocular vision and not to genetic variations between pigmented and albino animals.

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Section: Discussioncontrasting

confidence: 87%

“…The functional characteristics of eye muscle in albino (Siamese) cats and pigmented domestic cats have been shown to differ markedly (Lennerstrand 1979). Siamese extraocular muscle contracted slower and fatigued more easily than muscles of pigmented cats.…”

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confidence: 99%

Contractile properties and histochemistry of extraocular muscle in the pigmented and the albino guinea pig

Lennerstrand

1985

Acta Ophthalmologica

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“…GDNF was substantially downregulated in strabismic muscles, consistent with the report of a significantly slower contraction speed of strabismic muscle. 48 …”

Section: Discussionmentioning

confidence: 99%

“…59 VEGFA appeared slightly downregulated (but in our data set statistically insignificant) in strabismic EOMs, consistent with a known decreased capillary density in strabismic EOMs. 10,48 …”

Section: Discussionmentioning

confidence: 99%

Altered Protein Composition and Gene Expression in Strabismic Human Extraocular Muscles and Tendons

Agarwal

Feng

Altick

et al. 2016

Invest. Ophthalmol. Vis. Sci.

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PurposeTo determine whether structural protein composition and expression of key regulatory genes are altered in strabismic human extraocular muscles.MethodsSamples from strabismic horizontal extraocular muscles were obtained during strabismus surgery and compared with normal muscles from organ donors. We used proteomics, standard and customized PCR arrays, and microarrays to identify changes in major structural proteins and changes in gene expression. We focused on muscle and connective tissue and its control by enzymes, growth factors, and cytokines.ResultsStrabismic muscles showed downregulation of myosins, tropomyosins, troponins, and titin. Expression of collagens and regulators of collagen synthesis and degradation, the collagenase matrix metalloproteinase (MMP)2 and its inhibitors, tissue inhibitor of metalloproteinase (TIMP)1 and TIMP2, was upregulated, along with tumor necrosis factor (TNF), TNF receptors, and connective tissue growth factor (CTGF), as well as proteoglycans. Growth factors controlling extracellular matrix (ECM) were also upregulated. Among 410 signaling genes examined by PCR arrays, molecules with downregulation in the strabismic phenotype included GDNF, NRG1, and PAX7; CTGF, CXCR4, NPY1R, TNF, NTRK1, and NTRK2 were upregulated. Signaling molecules known to control extraocular muscle plasticity were predominantly expressed in the tendon rather than the muscle component. The two horizontal muscles, medial and lateral rectus, displayed similar changes in protein and gene expression, and no obvious effect of age.ConclusionsQuantification of proteins and gene expression showed significant differences in the composition of extraocular muscles of strabismic patients with respect to important motor proteins, elements of the ECM, and connective tissue. Therefore, our study supports the emerging view that the molecular composition of strabismic muscles is substantially altered.

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“…The motivation for this study was further derived from the fact that the speed of contraction is slowed in strabismic EOMs [34, 35]. The growth factors we examined here, as well as others, may be of clinical relevance in the context of strabismus and other disorders of EOMs [45, 66].…”

Section: Introductionmentioning

confidence: 99%

How to make rapid eye movements “rapid”: the role of growth factors for muscle contractile properties

Feng

Bartheld

2011

Pflugers Arch - Eur J Physiol

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Different muscle functions require different muscle contraction properties. Saccade-generating extraocular muscles (EOMs) are the fastest muscles in the human body, significantly faster than limb skeletal muscles. Muscle contraction speed is subjected to plasticity, i.e., contraction speed can be adjusted to serve different demands, but little is known about the molecular mechanisms that control contraction speed. Therefore, we examined whether myogenic growth factors modulate contractile properties, including twitch contraction time (onset of force to peak force) and half relaxation time (peak force to half relaxation). We examined effects of three musclederived growth factors: insulin-like growth factor 1 (IGF1), cardiotrophin-1 (CT1), and glial cell line-derived neurotrophic factor (GDNF). In gain-of-function experiments, CT1 or GDNF injected into the orbit shortened contraction time, and IGF1 or CT1 shortened half relaxation time. In lossof-function experiments with binding proteins or neutralizing antibodies, elimination of endogenous IGFs prolonged both contraction time and half relaxation time, while eliminating endogenous GDNF prolonged contraction time, with no effect on half relaxation time. Elimination of endogenous IGFs or CT1, but not GDNF, significantly reduced contractile force. Thus, IGF1, CT1, and GDNF have partially overlapping but not identical effects on muscle contractile properties. Expression of these three growth factors was measured in chicken and/or rat EOMs by real-time PCR. The "fast" EOMs express significantly more message encoding these growth factors and their receptors than skeletal muscles with slower contractile properties. Taken together, these findings indicate that EOM contractile kinetics is regulated by the amount of myogenic growth factors available to the muscle.

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Contractile Properties of Extraocular Muscle in Siamese Cat

Cited by 12 publications

References 19 publications

Contractile properties and histochemistry of extraocular muscle in the pigmented and the albino guinea pig

Contractile properties and histochemistry of extraocular muscle in the pigmented and the albino guinea pig

Altered Protein Composition and Gene Expression in Strabismic Human Extraocular Muscles and Tendons

How to make rapid eye movements “rapid”: the role of growth factors for muscle contractile properties

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