Intracellular free Ca2+ is one of important biological signals regulating a number of cell functions. It has been discussed widely and extensively in several cell types during the past two decades. Attention has been paid to the Ca2+ transportation in mesenchymal stem cells in recent years as mesenchymal stem cells have gained considerable interest due to their potential for cell replacement therapy and tissue engineering. In this paper, roles of intracellular Ca2+ oscillations and its transporters in mesenchymal stem cells have been reviewed., B. Ye., and Obsahuje bibliografii a bibliografické odkazy
We studied the potassium channel in the basolateral membrane of the rat proximal convoluted tubule as affected by cyclosporine A. Proximal convoluted tubules were dissected from the rat kidney under a stereoscopic microscope, without a preliminary enzyme treatment. The standard configuration for single-channel tight seal patch-clamp technique
was used to record channel currents. A small conductance, stretch-sensitive potassium channel could be observed spontaneously in most of the cell-attached patches as the gigaohm seal was formed. In the inside-out configuration, channel activity was diminished. The K+
channel appeared to be an inward rectifier. The limiting inward slope
conductance was 28.3±1.7 pS (Vp was between 40 mV and 80 mV, n=6) and the outward chord conductance was 5.6±0.3 pS (Vp was between -40 and -60 mV, n=5). The open dwell time constants of the potassium channel were 0.524 ms and 5.087 ms, while the closed dwell time constants were 1.029 ms and 16.500 ms. The opening probability of the
channel decreased when the extracellular fluid was acidified. Cyclosporine A had no significant effect on the potassium channel of the proximal tubular cell in the basolateral membrane at concentrations of 10 and 50 μg/ml, while at 100 μg/ml, it decreased the opening probability.