Nonstationary noise analysis and application to patch clamp recordings.

Publisher Summary This chapter discusses studies of nonstationary fluctuations of sodium currents in bovine adrenal chromaffin cells for estimating the temperature and pressure dependence of the conductance of voltage-activated sodium channels as an application of the analysis method. The procedure presented allows a rapid analysis of noise records obtained under nonideal experimental conditions based on objective selection criteria. Although single-channel analysis surpasses noise analysis in many instances, there are still regimes, where it cannot be successfully applied for various reasons. In this regard, nonstationary noise analysis retain its value for electrophysiological research in particular, as ever fainter electrical signals are being investigated in biological membranes. To demonstrate the methods, the temperature and pressure dependence of the sodium channel conductance are measured, and in both respects, the sodium channel shows features similar to other ion channels. Both findings are in accord with the physical picture of a rather free ion diffusion through the channel pore which, unlike the channel gating mechanism, does not involve protein rearrangements associated with measurable activation volumes.