Regulation of swelling-activated chloride channels in embryonic chick heart cells.
Swelling-activated Cl- currents, I(Cl,swell) were measured during hyposmotic shock in white Leghorn embryonic chick heart cells using the whole-cell recording of patch-clamp technique. Genistein, an inhibitor of protein tyrosine kinase (PTK), suppressed I(Cl,swell). Under isosmotic condition phorbol 12-myristate 13-acetate (PMA), an activator of PKC, elicited the Cl- current similar to that in hyposmotic solution, whereas hyposmotic shock did not elicit I(Cl,swell) in chelerythrine chloride(an inhibitor of PKC)-treated cells. Confocal microscopy experiments using FITC-phalloidin as a fluorescent label of F-actin showed that the actin network was moved from cortical region of the cell to the center after hyposmotic shock as compared with the image under isosmotic condition. When the cells were treated with cytochalasin B (CB) or cytochalasin D (CD) under isosmotic condition the disruption of the F-actin integrity was observed, and I(Cl,swell) was not elicited. With combination treatment of CB with PMA, hyposmotic solution could not elicited I(Cl,swell). The results suggested that the role of PTK, probably receptor tyrosine kinase, for regulation of I(Cl,swell) appeared to be at upstream site related to the role of F-actin. Then PKC signal pathway was activated somehow and finally change in the polymerization state of cytoskeleton led to activate the swelling-activated Cl- channels. These results demonstrate clearly that PTK, PKC and F-actin are important factors for regulation of I(Cl,swell), in embryonic chick heart cells as compared with often controversial results reported in different cell types.
Wei
Hua
H
Department of Physiology and Biophysics, Liren Laboratory, School of Life Sciences, Fudan University, Shanghai 200433, China.
Mei
Yan Ai
YA
Sun
Jia Ting
JT
Zhou
Han Qing
HQ
Zhang
Zhi Hong
ZH
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D000199:Actins / Q000378:metabolism; D000818:Animals; D002478:Cells, Cultured; D002642:Chick Embryo; D018118:Chloride Channels / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002746:Chlorpromazine / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019833:Genistein / Q000494:pharmacology; D006321:Heart / Q000196:embryology / Q000502:physiology*; D009206:Myocardium / Q000166:cytology; D009997:Osmotic Pressure; D018408:Patch-Clamp Techniques; D011493:Protein Kinase C / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D000199:Actins; D018118:Chloride Channels; D004791:Enzyme Inhibitors; D019833:Genistein; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D002746:Chlorpromazine