Potassium channel-dependent changes in the volume of developing mouse Schwann cells.
Physiological roles of voltage-gated K+ channels in developing mouse Schwann cells were investigated using whole-cell variation of the patch-clamp technique. In neonatal myelin-associated Schwann cells, local cytoplasmic swellings were induced when membrane potential (MP) was kept more negative than zero-current potential (membrane hyperpolarization) and they decreased in sizes when MP was kept positive. A lack of changes of cytoplasmic volume in Schwann cells of 17- to 18-day-old embryos or in neonatal myelin-associated cells in a solution containing Ba2+ suggested that activation of Ba(2+)-sensitive K+ channels caused cytoplasmic volume changes. Significant increase in magnitudes of Ba(2+)-sensitive K+ currents in neonatal myelin-associated cells after membrane hyperpolarization suggested that these K+ channels locate in adaxonal Schwann cell membrane and probably determine the sites of Schmidt-Lanterman incisures.
Konishi
T
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Department of Neurology, Utano National Hospital, Kyoto, Japan.
D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D001369:Axons / Q000502:physiology; D001464:Barium / Q000494:pharmacology; D017609:Barium Compounds; D002462:Cell Membrane / Q000502:physiology; D002712:Chlorides; D004553:Electric Conductivity; D004594:Electrophysiology; D004622:Embryo, Mammalian; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D011803:Quinine / Q000494:pharmacology; D012583:Schwann Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D012584:Sciatic Nerve / Q000196:embryology / Q000254:growth & development / Q000502:physiology*
D017609:Barium Compounds; D002712:Chlorides; D015221:Potassium Channels; C024986:barium chloride; D001464:Barium; D011803:Quinine