Muscle inactivity reduces the content of parvalbumin in rat thymic myoid cells in vitro.
We investigated the influence of muscle inactivity by the addition of 1 microM tetrodotoxin in culture medium (complete abolishment of spontaneous firings); feeding with 50 mM KCl in the culture medium (inactivation of action potentials by depolarization) and the addition of 50 microM dantrolene sodium in culture medium (excitation-contraction uncoupling) on the content of parvalbumin in a cultured rat thymic myoid cell line (R615B2: M cells) using a highly sensitive enzyme immunoassay for rat parvalbumin. This is the first report of the content of parvalbumin in thymic myoid cells. Our studies clearly show that the content of parvalbumin is significantly decreased in paralyzed M cells compared with controls which had continuous muscle contractions. It is strongly suggested that muscle contractile activity plays an important role on the expression of parvalbumin in thymic myoid cells.
Kobayashi
T
T
Department of Neurology, Tokyo Medical and Dental University, Japan.
Sano
M
M
Tsukagoshi
H
H
Kamo
I
I
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002460:Cell Line; D004797:Enzyme-Linked Immunosorbent Assay; D007124:Immunoenzyme Techniques; D008564:Membrane Potentials / Q000187:drug effects; D009132:Muscles / Q000502:physiology*; D010320:Parvalbumins / Q000378:metabolism*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D013779:Tetrodotoxin / Q000494:pharmacology; D013950:Thymus Gland / Q000166:cytology / Q000378:metabolism*
D010320:Parvalbumins; D013779:Tetrodotoxin; D011189:Potassium Chloride