title: Calcium uptake and release through sarcoplasmic reticulum in the inferior oblique muscles of patients with inferior oblique overaction.
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.
authors.affiliation: Department of Ophthalmology, Institute of Vision Research, Eye and ENT Hospital, Yonsei University of College of Medicine, 134 Shinchon-dong, Seodamun-gu, Seoul 120-752, Korea.
authors.forename: Hee Seon
authors.initials: HS
authors.lastname: Kim
authors.forename: Yoon-Hee
authors.initials: YH
authors.lastname: Chang
authors.forename: Do Han
authors.initials: DH
authors.lastname: Kim
authors.forename: So Ra
authors.initials: SR
authors.lastname: Park
authors.forename: Sueng-Han
authors.initials: SH
authors.lastname: Han
authors.forename: Jong Bok
authors.initials: JB
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism / Q000493:pharmacokinetics*; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D002155:Calsequestrin / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009132:Muscles / Q000473:pathology*; D015835:Ocular Motility Disorders / Q000378:metabolism* / Q000473:pathology*; D009801:Oculomotor Muscles; D010070:Oxalates / Q000378:metabolism; D012433:Ryanodine / Q000378:metabolism; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases
chemical_list: D002155:Calsequestrin; D010070:Oxalates; D019837:Ryanodine Receptor Calcium Release Channel; D012433:Ryanodine; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D000252:Calcium-Transporting ATPases; D002118:Calcium