Hypertonic Stress Increases the Na + Conductance of Rat Hepatocytes in Primary Culture

摘要: We studied the ionic mechanisms underlying regulatory volume increase of rat hepatocytes in primary culture by use confocal laser scanning microscopy, conventional and ion-sensitive microelectrodes, cable analysis, microfluorometry, measurements 86Rb+ uptake. Increasing osmolarity from 300 to 400 mosm/liter addition sucrose decreased cell volumes 88.6% within 1 min; thereafter, increased 94.1% control 10 min, equivalent a (RVI) 44.5%. This RVI was paralleled decrease input resistance specific membrane 88 60%, respectively. Ion substitution experiments (high K+, low Na+, Cl-) revealed that these effects are due an hepatocyte Na+ conductance. During RVI, ouabain-sensitive uptake augmented 141% control, K+ 148 180%, The increases conductance as well activation Na+/K(+)-ATPase were completely blocked 10(-5) mol/liter amiloride. At this concentration, amiloride had no effect on osmotically induced alkalinization via Na+/H+ exchange. When 220 (by readdition after preperiod 15 min which cells underwent decrease, RVD) initially 81.5%; thereafter 90.8% control. post-RVD-RVI 55.0% is also mediated conclude confluent capable post-RVD-RVI. In system, hypertonic stress leads considerable concert with conductive influx, then Na+/K(+)-ATPase. An additional role exchange regulation remains be defined.