Fig. 5.

Ni²⁺ and KB-R7943: NCX-blockers significantly decreased the stress-induced Ca²⁺ signal amplitude. (A) and (B) Time-courses of normalized fluorescence intensity in mdx cardiomyocytes (black circles) and in mdx cardiomyocytes pretreated with an NCX inhibitor (white circles). (A) Presence of 5 mM Ni²⁺ or (B) 20 µM KB-R7943 during the stress. (C) Mean normalized fluorescence intensity after the stress in mdx myocytes under control conditions (black bar) and in the presence of an inhibitor (white bar; number of cells was n=5 and 15 for controls, n=11, 15 for Ni²⁺ and KB-R7943, respectively). (D) Sample traces of normalized Ca²⁺ signals appearing after the washout of 5 mM Ni²⁺ or 20 µM KB-R7943 as indicated by line bars.