1,4-Dihydropyridine receptor associated with Ca2+ channels in human embryonic fibroblasts.
By using the radioactively labeled 1,4-dihydropyridine (DHP) probe, [3H]PMD, we have demonstrated that cultured human embryonic fibroblasts grown at a low density in Eagle's medium supplemented with serum contain a single class of non-interacting DHP binding sites (Bmax, 1.2 +/- 0.3 pmol/10(6) cells; Kd, 3.9 nM). After inhibition of the DHP receptor biosynthesis by cycloheximide, the number of [3H]PMD binding sites is reduced with a half-time of 12 h, which implies a turnover rate of 30,000 +/- 7500 receptors/h per cell. With progression to confluency, the Bmax value decreased up to 0.28 +/- 0.08 pmol/10(6) cells without significant change in Kd value. When cells were grown at a low density in serum-free conditions, the number of [3H]PMD binding sites gradually increased 1.9-fold within 3 days. Addition of serum reversed this effect with the same time course. These results imply that the DHP-sensitive Ca2+ channels are involved in the control of the proliferation of human embryonic fibroblasts.
Dudkin
S M
SM
Institute of Biomedical Technology, USSR Ministry of Public Health, Moscow.
Gnedoj
S N
SN
Chernyuk
N N
NN
Soldatov
N M
NM
D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000378:metabolism; D015220:Calcium Channels; D004095:Dihydropyridines / Q000378:metabolism*; D004622:Embryo, Mammalian; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D007473:Ion Channels / Q000378:metabolism*; D007700:Kinetics; D011978:Receptors, Nicotinic / Q000378:metabolism*
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D004095:Dihydropyridines; D007473:Ion Channels; D011978:Receptors, Nicotinic; C038806:1,4-dihydropyridine; D002118:Calcium