Figure 1.

Effect of I_NaL activation on APD, [Ca²⁺]_i transient and cell shortening in canine isolated ventricular myocytes. ATX-II 2 nM significantly enhanced the I_NaL current by apparently slowing its inactivation kinetics (A). As a consequence, APD was lengthened (B) and the amplitude of the [Ca²⁺]_i transient was also increased (C), leading to an enhanced cell shortening (D). Columns and bars represent means ± SEM values; asterisks (*) denote significant differences from control (P < 0.05). AU represents arbitrary units.