Electrophysiological characterization of cultured hepatic stellate cells in rats.
This study aimed to examine electrophysiological properties of cultured 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 and inward-rectifying K+ current. The third component was a current flowing outward, which was activated when the cell was depolarized more positively than 0 mV. The channel for this current allowed Na+, K+, and Cl- to pass nonspecifically, suggesting the presence of hemi gap-junctional channel. Furthermore, a laser photobleaching technique revealed the presence of gap junctions between adjacent HSCs. A voltage-gated Ca2+ current, which is known to occur in smooth muscle cells, was searched for but was not detectable. These results suggest that membrane potential of HSCs is determined specifically by the two distinct K+ channels and by an intercellular mechanism involving gap-junctional communication.
Kashiwagi
S
S
Department of Biochemistry, School of Medicine, Keio University, Tokyo, Japan.
Suematsu
M
M
Wakabayashi
Y
Y
Kawada
N
N
Tachibana
M
M
Koizumi
A
A
Inoue
M
M
Ishimura
Y
Y
Kaneko
A
A
D000818:Animals; D015220:Calcium Channels / Q000502:physiology; D002450:Cell Communication; D002478:Cells, Cultured; D004553:Electric Conductivity; D004594:Electrophysiology; D017629:Gap Junctions / Q000502:physiology; D007473:Ion Channels / Q000502:physiology; D008099:Liver / Q000166:cytology* / Q000502:physiology*; D008297:Male; D008564:Membrane Potentials; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar
D015220:Calcium Channels; D007473:Ion Channels; D015221:Potassium Channels