Fig. 5.
Coexpression of both Kv1.5W461F and Kv4.2W362F eliminates IAf. Isolated SCG neurons were transfected with Kv1.5W461F, Kv4.2W362F, and EGFP using the Biolistic Gene Gun (as described in Materials and Methods), and outward K+ currents were recorded from EGFP-positive cells as described in the legend to Figure 1. Two distinct current waveforms were evident in these recordings: the vast majority (76%) of cells were found to express only IK andISS and were classified as type III (B); the remaining cells (24%) expressIAs,IK, andISS, and, therefore, are type II cells lacking IAf (A). The fast transient current IAf was not detected in any of these cells (n = 15). Analysis of the decay phases of the currents revealed that the densities ofIAs,IK, andISS in Kv1.5W461F + Kv4.2W362F-expressing type II and III cells are indistinguishable from the currents in wild-type II and III cells (Table 1).