Potassium as a signal for both proliferation and differentiation of rabbit retinal (Müller) glia growing in cell culture.
Retinal glial (Müller) cells were grown from explants of early postnatal rabbit retinae. The resulting monolayers of flat cells were exposed to control media (containing 5.85 mM K+), and to media with enhanced K+ concentrations (10 and 20 mM) or arginine-vasopressin (AVP, 20 micrograms/ml) or epithelial growth factor (EGF, 10 ng/ml). Autoradiographically, protein synthesis was quantified as L-[3H]-lysine incorporation, and DNA synthesis as [3H]-thymidine incorporation. Furthermore, the activity of Na+,K(+)-ATPase was measured radiochemically. Short exposure to either moderately enhanced K+ concentrations (10 mM) or to AVP, stimulated L-[3H]-lysine incorporation into the cells. Long-lasting exposure to either high K+ concentrations (20 mM) or to EGF stimulated [3H]-uptake. The Na+,K(+)-ATPase activity of cell cultures increased with increasing K+ concentration of the media. It is suggested that release of K+ by active neuronal compartments stimulates local protein synthesis of glial cells, resulting in the formation of glial sheaths with active K+ uptake capacity. Strong K+ release may even induce glial proliferation.
Reichelt
W
W
Carl Ludwig Institute of Physiology, Karl Marx University, DDR, Leipzig.
Dettmer
D
D
Brückner
G
G
Brust
P
P
Eberhardt
W
W
Reichenbach
A
A
D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology; D002454:Cell Differentiation; D002455:Cell Division; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D008239:Lysine / Q000378:metabolism; D009457:Neuroglia / Q000166:cytology* / Q000378:metabolism; D011188:Potassium / Q000378:metabolism*; D011817:Rabbits; D012160:Retina / Q000166:cytology* / Q000378:metabolism; D015398:Signal Transduction; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013936:Thymidine / Q000378:metabolism
D001127:Arginine Vasopressin; D004247:DNA; D000254:Sodium-Potassium-Exchanging ATPase; D008239:Lysine; D011188:Potassium; D013936:Thymidine