[Effect of interleukin-2 on the activity of Ca2+ ATPase and Na+/K+ ATPase of sarcoplasmic reticulum and sarcolemma].
The purpose of the present study was to investigate whether interleukin-2 (IL-2) changes the activity of sarcoplasmic reticulum (SR) Ca(2+) ATPase, sarcolemmal Ca(2+)ATPase and Na(+)/K(+) ATPase by measuring the Pi liberated from ATP hydrolysis with colorimetrical methods. It was shown that the activity of Ca(2+)ATPase in SR from IL-2-perfused (10, 40, 200, 800 U/ml) rat heart increased dose-dependently. After incubation of the SR with ATP (0.1 approximately 4 mmol/L), the activity of SR Ca(2+)ATPase increased dose-dependently in the control group. In the SR from 200 U/ml IL-2-perfused hearts, the activity of Ca(2+)ATPase was much higher than that in the control group. On the other hand, incubation of the SR with Ca(2+) (1 approximately 40 micromol/L) increased the activity of SR Ca(2+) ATPase in the control group. The activity of SR Ca(2+)ATPase of IL-2-perfused hearts was inhibited as the function to Ca(2+). Pretreatment with specific kappa-opioid receptor antagonist nor-BNI (10 nmol/L) for 5 min attenuated the effect of IL-2 (200 U/ml) on the activity of SR Ca(2+) ATPase. After pretreatment with pertussis toxin (PTX, 5 mg/L) or U73122 (5 micromol/L), IL-2 failed to increase SR Ca(2+)ATPase activity. The activity of SR Ca(2+)ATPase was not changed by incubation of SR isolated from normal hearts with IL-2. Perfusion of rat heart with IL-2 did not affect the activity of sarcolemmal Ca(2+)ATPase and Na(+)/K(+)ATPase. It is concluded that perfusion of rat heart with IL-2 increases the activity of SR Ca(2+)ATPase dose-dependently, which is mainly mediated by cardiac kappa-opioid receptor pathway including a PTX sensitive Gi-protein and phospholipase C. IL-2 increases the activity of SR Ca(2+)ATPase as the function to ATP, but inhibits the activity of SR Ca(2+)ATPase as the function to Ca(2+). IL-2 has no effect on the activity of sarcolemmal Ca(2+)ATPase and Na(+)/K(+)ATPase.
Cao
Chun-Mei
CM
Department of Physiology, Department of Cardiology of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310031.
Xia
Qiang
Q
Fu
Chen
C
Jiang
Hui-Di
HD
Ye
Zhi-Guo
ZG
Shan
Yue-Liang
YL
Chan
Jun-Zhu
JZ
D000818:Animals; D007376:Interleukin-2 / Q000494:pharmacology*; D008297:Male; D009206:Myocardium / Q000201:enzymology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012508:Sarcolemma / Q000201:enzymology*; D012519:Sarcoplasmic Reticulum / Q000201:enzymology; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D007376:Interleukin-2; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase