Calcium uptake and release through sarcoplasmic reticulum in the inferior oblique muscles of patients with inferior oblique overaction.
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.
Kim
Hee Seon
HS
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.
Chang
Yoon-Hee
YH
Kim
Do Han
DH
Park
So Ra
SR
Han
Sueng-Han
SH
Lee
Jong Bok
JB
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
D002155:Calsequestrin; D010070:Oxalates; D019837:Ryanodine Receptor Calcium Release Channel; D012433:Ryanodine; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D000252:Calcium-Transporting ATPases; D002118:Calcium