Nerve growth factor and fibroblast growth factor influence post-fusion expression of Na-channels in cultured rat skeletal muscle

✍ Scribed by Chaya Brodie; S. R. Sampson

• Publisher: John Wiley and Sons
• Year: 1990
• Tongue: English
• Weight: 702 KB
• Volume: 144
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.1041440317

✦ Synopsis

We have examined effects of nerve growth factor (NGF) and fibroblast growth factor (FCI) on the density of tetrodotoxin 1TTX)-sensitive Na-channels in cultured rat skeletal muscle. Measurements were made of specific binding of ['Hlsaxitoxin (STX) and the frequency and rate of rise of spontaneously occurring action potentials, the physiological expression of Na-channel density. Cells were transferred to various growth conditions at 6 days in vitro, and measurements were made beginning 24 hr later. Both growth factors (GF) caused dose-related increases in Na-channels compared with myotubes maintained in normal, serumsupplemented growth medium. Maximum effects occurred with a concentration of NLF of 50 n d m l and F G I of 15 nginil. Scatchard analysis of specific STX binding showed an increase in B , , , , with no significdnt change in K, . Similar increases occurred on rate of rise and frequency spontaneous action potentials. Treatment of culture5 with cycloheximide or actinomycin D, inhibitors of protein and RNA synthesis, completely prevented the increase in STX-binding induced by CF treatment. The re5ults indicate that NGF and F L F have important effects on regulation of excitable cell gene products after differentiation.