Alterations in sarcoplasmic reticulum function and gene expression in ischemic-reperfused rat heart.
In view of the critical role of sarcoplasmic reticular (SR) Ca(2+) release and the Ca(2+) pump in cardiac contraction-relaxation, this study was undertaken to assess the status of SR function, protein content, and gene expression in isolated rat hearts subjected to global ischemia for 30 min followed by 60 min of reperfusion (I/R). Attenuated recovery of contractile function in the I/R hearts was associated with reduced SR Ca(2+) uptake, Ca(2+) release, and ryanodine-binding activities. mRNA levels and protein contents for SR Ca(2+) pump ATPase and Ca(2+) release channels were markedly depressed in the I/R hearts. Perfusion of hearts with superoxide dismutase plus catalase, well-known scavengers of oxyradicals, prevented the I/R-induced alterations in cardiac function and partially prevented SR Ca(2+) transport activities and mRNA abundance. In hearts perfused with xanthine plus xanthine oxidase or H(2)O(2), changes similar to those in the I/R hearts were observed. These results indicate that oxyradicals may participate in depressing the SR Ca(2+) handling and gene expression in the I/R heart. It is suggested that treatment of hearts with antioxidants may improve the recovery of cardiac function by preserving the SR function and partially protecting the SR gene expression.
Temsah
R M
RM
Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada R2H 2A6.
Netticadan
T
T
Chapman
D
D
Takeda
S
S
Mochizuki
S
S
Dhalla
N S
NS
D000818:Animals; D002118:Calcium / Q000378:metabolism; D015870:Gene Expression; D006321:Heart / Q000503:physiopathology; D066298:In Vitro Techniques; D008297:Male; D017202:Myocardial Ischemia / Q000235:genetics* / Q000503:physiopathology*; D015428:Myocardial Reperfusion Injury / Q000235:genetics* / Q000503:physiopathology*; D009206:Myocardium / Q000378:metabolism; D010477:Perfusion; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D012519:Sarcoplasmic Reticulum / Q000378:metabolism / Q000502:physiology*
D017382:Reactive Oxygen Species; D002118:Calcium