Ionic control of locomotion and shape of epithelial cells: II. Role of monovalent cations.
The migration of keratocytes isolated from Xenopus tadpole epidermis has been investigated in vitro. In saline the cells move with a mean speed of 5-6 microns/min. Migration is slowed down in saline with diminished sodium content and ceases in media containing not more than 4 mM sodium. Inhibition of the Na+/K+-2Cl- cotransporter by piretanide reduces the speed of migrating cells to about one-third of the control level, the same accounts to inhibition of the Na+/H+ antiport with amiloride at pH 7.2. At pH 6.6, however, amiloride only slightly influences locomotion. Depolarization of the plasma membrane by increased extracellular K+ concentration or by inhibition of the Na+/K+ pump by ouabain is only of minor influence during more than 1 h. Hyperpolarization of the cells using the sodium ionophore monensin impedes locomotion; this inhibition depends on an active Na+/K+ pump. Ionophore-mediated breakdown of the K+ gradient strictly inhibits locomotion. The experiments have shown that a continuous flux of sodium ions is indispensable for the maintenance of cell locomotion. These ions may exert their action primarily by affecting cytosolic free calcium concentration and pH.
Bereiter-Hahn
J
J
Cinematic Cell Research Group, Johann Wolfgang Goethe-Universität, Frankfurt/M., Federal Republic of Germany.
Vöth
M
M
D000584:Amiloride / Q000494:pharmacology / Q000502:physiology; D000818:Animals; D002414:Cations, Monovalent / Q000494:pharmacology / Q000502:physiology*; D002465:Cell Movement / Q000187:drug effects; D003593:Cytoplasm / Q000187:drug effects; D000078404:Epidermal Cells; D004817:Epidermis / Q000032:analysis / Q000648:ultrastructure; D004847:Epithelial Cells; D004848:Epithelium / Q000187:drug effects / Q000502:physiology; D006859:Hydrogen / Q000493:pharmacokinetics; D007633:Keratins / Q000032:analysis*; D008564:Membrane Potentials / Q000187:drug effects; D008985:Monensin / Q000494:pharmacology / Q000502:physiology; D011188:Potassium / Q000032:analysis / Q000493:pharmacokinetics / Q000494:pharmacology; D012964:Sodium / Q000032:analysis / Q000493:pharmacokinetics / Q000494:pharmacology; D000254:Sodium-Potassium-Exchanging ATPase / Q000494:pharmacology; D013449:Sulfonamides / Q000494:pharmacology / Q000502:physiology; D014634:Valinomycin / Q000494:pharmacology; D014982:Xenopus laevis
D002414:Cations, Monovalent; D013449:Sulfonamides; D014634:Valinomycin; D007633:Keratins; D000584:Amiloride; D006859:Hydrogen; D008985:Monensin; D012964:Sodium; C015451:piretanide; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium