Computer programs to facilitate the estimation of time-dependent drug effects on ion channels

The programs I_VOC and I_ROC have been designed to facilitate the analysis of drug effects on currents through ion channels in the cell membrane, measured by means of voltage-clamp. They are written in Igor Pro (WaveMetrics) and read exported files or raw data files generated by the Pulse (HEKA Electronic) or pClamp (Axon Instruments) programs. With I_VOC, the sweeps of current through voltage-operated ion channels can be quantified within six time ranges, and current run-down can be corrected for after the currents are fitted during the control period. Linear leak current can be subtracted even when the P/n method is not used. The results are plotted and tabulated. With I_ROC, an analogous program, receptor-operated currents can be quantified, the peak current or rate of desensitization can be fitted and run-down corrected for. Chart-like data can be converted to a sweep-like format. Several procedures are incorporated for rapid graphical data presentation. These programs accelerate and improve the estimation of drug effects on ion channels. (C) 2003 Elsevier Ireland Ltd. All rights reserved.