Cardiac dysfunction induced by oxidants: Alteration of β-adrenergic stimulation


TURAN B. , Hotomaroglu O., DEMİREL YILMAZ E., Vassort G.

FASEB Journal, vol.11, no.3, 1997 (Journal Indexed in SCI Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 11 Issue: 3
  • Publication Date: 1997
  • Title of Journal : FASEB Journal

Abstract

The present study was designed to investigate and compare the effects of dietary antioxidants on the mechanical and electrophysiological characteristics of the rat heart. Both sex weanling rats were fed a standardized selenium (Se) and vitamin E deficient diet (GI). or a Se excess diet (GII), or a control diet (GIII). In vitro papillary muscle and Langendorff perfused heart functions of GI and GII did reveal impaired contractile performance and increased heart rate and coronary perfussion pressure. The L-type calcium current (ICa) was investigated in GI, GII and GIII rat ventricular myocytes as a possible cause of cardiac dysfunction. The ICa and current densities measured in GI and GII heart cells (1.4±0.6nA and 8.9±2.8pA/pF; 1.6±.7nA and 8.6±3.2pA/pF) were not significantly different from the values of GIII cells (1.3±0.5nA and 7.0±2.5pA/pF). When expressed as a %, the maximal increase in the peak contractile force of papillary muscle and ICa amplitude that was obtained with 1 mM isoproterenol (ISO) were less in GI and GII (26% and 20%; 34% and 30%) than in GIII (80% and 90%). The voltage and time dependence of ICa in GI and GII showed some significant alterations. Stimulation of ICa, by ISO was decreased in agreement with a reduced number of binding sites of β-agonists and/or an altered secondary intracellular mechanisms. In conclusion, our data has shown that the diet antioxidants levels are important for maintenance of cardiac functions.