| Nonequilibrium Response Spectroscopy (NRS), the technique of using rapidly fluctuating voltage pulses in the study of ion channels is applied here. NRS is known to drive an ensemble of ion channels far from equilibrium where it has been argued that new details of ion channel kinetics can be studied under nonequilibrium conditions. In this study, single pulse NRS technique with custom designed waveforms built from wavelets are used. Two series of experiments were implemented using custom designed pulses, which were obtained using a pulse search algorithm with suitable ‘cost functionals’ as constraints in the design of the pulse. The use of NRS pulses in model selection was investigated, as well as an in the analysis of model topology through parametric optimization. Electrophysiological recordings (whole cell ionic current measurements) were made from mammalian cells (HEK 293) which stably expressed the sodium ion channel. Wavelet analysis of the model response and the experimental data is introduced. Its effectiveness in the data analysis is demonstrated in the unique plots of the wavelet transforms. The results show how these new NRS pulses can be applied in a systematic way to study ion channels gating kinetics. |
