Yonsei Med J.  2006 Apr;47(2):207-213. 10.3349/ymj.2006.47.2.207.

Calcium Uptake and Release through Sarcoplasmic Reticulum in the Inferior Oblique Muscles of Patients with Inferior Oblique Overaction

• Kim HS
• Chang YH
• Kim DH
• Park SR
• Han SH
• Lee JB

• KMID: 1110744
• DOI: http://doi.org/10.3349/ymj.2006.47.2.207

Abstract

We characterized and compared the characteristics of Ca2+ movements through the sarcoplasmic reticulum of inferior oblique muscles in the various conditions including primary inferior oblique overaction (IOOA), secondary IOOA, and controls, so as to further understand the pathogenesis of primary IOOA. Of 15 specimens obtained through inferior oblique myectomy, six were from primary IOOA, 6 from secondary IOOA, and the remaining 3 were controls from enucleated eyes. Ryanodine binding assays were performed, and Ca2+ uptake rates, calsequestrins and SERCA levels were determined. Ryanodine bindings and sarcoplasmic reticulum Ca2+ uptake rates were significantly decreased in primary IOOA (p < 0.05). Western blot analysis conducted to quantify calsequestrins and SERCA, found no significant difference between primary IOOA, secondary IOOA, and the controls. Increased intracellular Ca2+ concentration due to reduced sarcoplasmic reticulum Ca2+ uptake may play a role in primary IOOA.

Keyword

Calcium; calsequestrin; inferior oblique overaction; ryanodine receptor; sarcoplasmic reticulum; sarcoplasmic reticulum Ca2+ - ATPase 1

MeSH Terms

Sarcoplasmic Reticulum Calcium-Transporting ATPases
Sarcoplasmic Reticulum/*metabolism
Ryanodine Receptor Calcium Release Channel/metabolism
Ryanodine/metabolism
Oxalates/metabolism
Oculomotor Muscles
Ocular Motility Disorders/*metabolism/*pathology
Muscles/*pathology
Models, Statistical
Middle Aged
Male
Humans
Female
Child, Preschool
Child
Calsequestrin/metabolism
Calcium-Transporting ATPases/metabolism
Calcium/metabolism/*pharmacokinetics
Blotting, Western
Aged
Adult
Adolescent