Inhibition of elastin synthesis by high potassium salt is mediated by Ca2+ influx in cultured smooth muscle cells in vitro: reciprocal effects of K+ on elastin and collagen synthesis.
Elastin synthesis in cultured smooth muscle cells was inhibited by one fourth in the presence of 0.1 M K+ in the medium. The degree of inhibition paralleled the decrease in the steady-state levels of elastin mRNA. The inhibition of elastin synthesis was blocked by addition of 1 microM nifedipine, a Ca2+ antagonist. Comparable inhibition of elastin synthesis was observed by addition of A23187, a Ca2+ ionophore. In contrast, collagen synthesis and thymidine uptake were stimulated threefold and twofold respectively in the presence of 0.1 M K+ with a concomitant increase in collagen mRNA. The stimulation of collagen synthesis was also blocked by nifedipine. These results indicate that K+ modulates elastin and collagen synthesis and their gene expression reciprocally, and these effects are mediated by Ca2+ influx. Thus K+ exerts profound effects on the composition of extracellular matrices in aorta.
Tokimitsu
I
I
Department of Dermatology, Keio University School of Medicine, Tokyo.
Tajima
S
S
D000199:Actins / Q000096:biosynthesis; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D002642:Chick Embryo; D003094:Collagen / Q000096:biosynthesis*; D004305:Dose-Response Relationship, Drug; D004549:Elastin / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D004591:Electrophoresis, Polyacrylamide Gel; D015151:Immunoblotting; D017136:Ion Transport / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D009543:Nifedipine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology
D000199:Actins; D012333:RNA, Messenger; D012965:Sodium Chloride; D011189:Potassium Chloride; D003094:Collagen; D004549:Elastin; D009543:Nifedipine; D002118:Calcium