Interpretation of relevance of sodium-calcium exchange in action potential of diabetic rat heart by mathematical model

YARAŞ N., Turan B.

MOLECULAR AND CELLULAR BIOCHEMISTRY, vol.269, no.1-2, pp.121-129, 2005 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 269 Issue: 1-2
  • Publication Date: 2005
  • Doi Number: 10.1007/s11010-005-3439-8
  • Journal Name: MOLECULAR AND CELLULAR BIOCHEMISTRY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.121-129
  • Keywords: sodium selenite, action potential, calcium current, potassium current, sodium-calcium exchanger, diabetes, NA-CA-EXCHANGE, VENTRICULAR MYOCYTES, INTRACELLULAR CA2+, POTASSIUM CURRENTS, K+ CURRENTS, SELENIUM, INSULIN, CA-2+, CARDIOMYOPATHY, CONTRACTILITY
  • Ankara University Affiliated: No

Abstract

Sarcolemmal Na+-Ca2+ exchange plays a central role in ion transport of the myocardium and the current carried with it contributes to the late phase of the action potential (AP) besides the contribution of outward K+-currents. In this study, the mathematical model for AP of the diabetic rat ventricular myocytes [34] was modified and used for the diabetic rat papillary muscle. We used our experimentally measured values of two K+-currents; transient outward current, I-to and steady-state outward current, I-ss, as well as L-type Ca2+-current, I-CaL, then compared with the simulated values. We have demonstrated that the prolongation in the AP of the papillary muscle of the diabetic rats are not due to the alteration of I-CaL but mainly due to the inhibition of the K+-currents and also the Na+-Ca2+ exchanger current, INa-Ca. In combination with our experimental data on sodium-selenite-treated diabetic rats, our simulation results provide new information concerning plausible ionic mechanisms, and second a possible positive effect of selenium treatment on the altered INa-Ca for the observed changes in the AP duration of streptozotocin-induced diabetic rat heart.