Fig. 2.

2-meSATP increases Na⁺/Ca²⁺ exchanger (NCX) current (I_NCX). I_NCX, represented by Ni²⁺-sensitive current, in P2X4R TG ventricular myocytes was determined. A: representive trace showing membrane current when 10 mM Ni²⁺ was applied (time period bracketed by downward and upward arrows) under CTR conditions, during 2-meSATP application, and after WO. B, top: descending voltage ramps from 80 to −100 mV were used to contruct the current-voltage (I–V) relationship. Bottom, typical traces of membrane currents under CTR conditions and in the presence of Ni²⁺. C: mean I–V relationships of Ni²⁺-sensitive current under CTR conditions and in the presence of 2-meSATP. n = 10 myocytes from 8 TG mice. *P < 0.05. D: 2-meSATP increased the Ca²⁺ entry mode of I_NCX. Representative traces are shown for Ni²⁺ -sensitive currents at +30 mV before and after 2-meSATP application in a TG myocyte. E: plot of Ni²⁺-sensitive current at 30 mV under CTR conditions and during 2-meSATP application. n = 7 cells from 5 TG mice. P < 0.05.