Citations : pCLAMP™

By means of data sampling interface and analysis software of PCLAMP microcomputer processing system, Neural discharge signal was sampled and analyzed． Xetting some parameters of sampling parameter＇s table and analysis parameter＇s table of FETCHEX,neural discharge signal was Xampled,and analyzed the signal automatically．Using this method ,the neural discharge in rostral ventrolateral medulla in rat was analyzed, the result was satisfactory．

Using blind whole cell recording technique on rat hippocampal slices, the function and mechanisms of P/N leak subtraction of Clampex program in pClamp acquisition software were studied. The ways of picking up sub-pulse current and properly selecting parameters, including time course, polarization, sub-holding potential, numbers and location of P/N sub-pulse were analyzed in detail. Our results indicate that voltage-gated ion channel currents recorded by Clampex will be more accurate and reproducible by properly using P/N leak subtraction.

The patch-clamp technique has been used to investigate single-channel and whole cell conductances in freshly isolated rat hepatocytes. Whole cell experiments, with high (144 mM) intracellular and extracellular potassium as the principal conductive species, show some variation between cells in the current-voltage relationship (mean whole-cell conductance at physiological potentials being 2.7 nS). This may suggest functional heterogeneity of cells. The most common finding is that the current-voltage relationship shows inward rectification. This is reflected in cell-attached single-channel recordings in which channels displaying strong inward rectification and K+ selectivity are seen. The channels show a mean inward conductance (with 144 mM potassium in the pipette) of 44 pS and an outward conductance of 23 pS. The open probability is not voltage dependent, and the channels do not exhibit calcium dependence. The channels are quite different from others described in hepatocytes, but they show marked similarities to channels recently described in renal epithelial cells. Current-voltage relationships in the whole cell mode exhibit an increase in slope conductance at large hyperpolarizing and depolarizing potentials.