Hypertonic activation of phospholemman in solitary rat hepatocytes in primary culture.
Under hypertonic conditions, solitary rat hepatocytes in primary culture shrink and subsequently exhibit a distinct regulatory volume increase (RVI). Reverse-transcribed polymerase chain reaction and 5' and 3' RACE (rapid amplification of cDNA ends) techniques reveal that these cells express phospholemman (PLM). In whole-cell recordings, the hypertonic activation of a channel is observed that resembles PLM with respect to unitary conductance (600-700 pS), gating pattern, and non-selectivity for Na(+) over K(+). In Xenopus oocytes expressing hepatocyte PLM, hypertonic stress induces a non-selective cation conductance and noise analysis reveals the activation of a channel with a unitary conductance of approximately 700 pS. These results suggest a role of PLM in the RVI of rat hepatocytes.
Kirschner
Udo
U
Max-Planck-Institut für molekulare Physiologie, Abteilung Epithelphysiologie, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany.
Van Driessche
Willy
W
Werner
Andreas
A
Wehner
Frank
F
D000818:Animals; D002478:Cells, Cultured; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology*; D022781:Hepatocytes / Q000502:physiology*; D006982:Hypertonic Solutions; D007700:Kinetics; D008564:Membrane Potentials / Q000502:physiology; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D009865:Oocytes / Q000502:physiology; D018408:Patch-Clamp Techniques; D010750:Phosphoproteins / Q000235:genetics* / Q000378:metabolism; D018075:RNA, Complementary / Q000235:genetics; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014982:Xenopus laevis
D006982:Hypertonic Solutions; D008565:Membrane Proteins; D010750:Phosphoproteins; D018075:RNA, Complementary; C069141:phospholemman