Abstract
We investigated the effect of external Cd2+ on the Na/Ca exchange and the L-type Ca channel current (ICa,L) in whole cell patch-clamped rabbit ventricular myocytes at 36 degrees C. After the interfering ion channels and the Na/K pump were blocked, the exchange current was measured as the membrane current that was inhibited by 5 mM nickel. External Cd2+ inhibited Na/Ca exchange with a dissociation constant (KD) of 320.6 +/- 12.4 microM and a Hill coefficient of 1.5 +/- 0.09 (n = 13 cells) and ICa,L with a KD of 2.14 +/- 0.15 microM and a Hill coefficient of 0.74 +/- 0.03 (n = 11 cells). We observed some overlap in the Cd2+ concentration that blocked each mechanism. Cd2+ (100-500 microM) is used commonly to block ICa,L completely. However, 100 microM Cd2+ also inhibits 20% of the Na/Ca exchange activity, whereas 500 microM Cd2+ inhibits 60%.
Citations
Jan 11, 2005·Journal of Applied Physiology·Janny BøkenesOle M Sejersted
Oct 4, 2011·High Altitude Medicine & Biology·Demosthenes G PapamatheakisSean M Wilson
Mar 15, 2001·Journal of Applied Physiology·K N JewR L Moore
May 30, 2014·Journal of Neurophysiology·Jian-Rong ZhouKazuo Takahama
Sep 20, 2000·American Journal of Physiology. Heart and Circulatory Physiology·Y KusakaI Kifor
Nov 6, 2004·The Journal of Physiology·Asunción RocherLaura Almaraz
Feb 1, 2005·American Journal of Physiology. Heart and Circulatory Physiology·Zuojun Ren, Clive M Baumgarten
Mar 30, 2001·The Journal of Biological Chemistry·Z WangJ A Hill
Oct 22, 2002·American Journal of Physiology. Regulatory, Integrative and Comparative Physiology·Kyung Hwan SeulSuhn Hee Kim
Sep 16, 2011·American Journal of Physiology. Regulatory, Integrative and Comparative Physiology·Danielle F FelicianoJosé W M Bassani
Sep 25, 2007·American Journal of Physiology. Heart and Circulatory Physiology·Uwe KirchheferJoachim Neumann
Feb 9, 2021·ELife·Carlos Manlio Díaz-GarcíaGary Yellen
Aug 8, 2020·Food and Chemical Toxicology : an International Journal Published for the British Industrial Biological Research Association·Boris A KatsnelsonYuri L Protsenko