ELECTROPHYSIOLOGICAL CHARACTERIZATION OF CULTURED HEPATIC STELLATE CELLS IN RATS

This study aimed to examine electrophysiological properties of culture d rat hepatic stellate cells (HSCs) using the whole cell configuration of patch-clamp technique. At least three different current components were identified. First, when the membrane was depolarized to voltages more positive than -40 mV, a transient outward K+ current was evoked. Second, membrane hyperpolarization below -60 mV evoked a sustained an d inward-rectifying K+ current. The third component was a current flow ing outward, which was activated when the cell was depolarized more po sitively than 0 mV. The channel for this current allowed Na+, K+, and Cl- to pass nonspecifically, suggesting the presence of hemi gap-junct ional channel. Furthermore, a laser photobleaching technique revealed the presence of gap junctions between adjacent HSCs. A voltage-gated C a2+ current, which is known to occur in smooth muscle cells, was searc hed for but was not detectable. These results suggest that membrane po tential of HSCs is determined specifically by the two distinct K+ chan nels and by an intercellular mechanism involving gap-junctional commun ication.