Figure 9.
Estimation of INCX as a SEA0400- or ORM10103-sensitive current during an AP. In order to estimate the kinetics of NCX during a representative AP, (A) SEA0400 and ORM10103 were applied, and the NCX current was estimated as a subtracted current. Under control conditions, only negligible (outward) revINCX could be observed during the early phase of the AP. The current rapidly turned into (inward) fwdINCX (see B and C, open squares). Application of 2 nM ATX-II (B and C, filled square) induced an apparent increase in the composite current; thus, after current subtraction, the amplitude of the reverse component was enhanced, the reversal time delayed (see also the bar graphs in D, left for SEA0400 right for ORM10103). The amplitude of the forward component was also enhanced (bar graphs in E, left for SEA0400 right for ORM10103). Note that the net charge carried by a current component may change differently from the amplitude of the respective peak current.