Voltage dependent calcium channel expression in isolated osteoclasts.
In this study the expression of voltage-dependent calcium channels on osteoclast plasma membrane has been investigated. We found that osteoclasts were sensitive to KCl-induced depolarization. In this circumstance a 4 fold transient cytosolic calcium concentration ([Ca2+]i) increase was observed. This increase was dose-dependent. Its half maximal effect was achieved at 30 mM KCl. Voltage sensitive calcium channels in osteoclasts were inhibited by specific antagonists. Nicardipine, a dihydropyridine derivative, was the most effective, inducing complete block of the channels at 10(-6) M. Verapamil (phenylalkylamine) and diltiazem (benzodiazepine) were less effective. These results are consistent with the presence, on the osteoclast membrane, of L-type voltage-sensitive calcium channels.
Teti
A
A
Grano
M
M
Colucci
S
S
Argentino
L
L
Barattolo
R
R
Miyauchi
A
A
Teitelbaum
S L
SL
Hruska
K A
KA
Zambonin Zallone
A
A
D000818:Animals; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology*; D002462:Cell Membrane / Q000502:physiology; D002478:Cells, Cultured; D002645:Chickens; D004110:Diltiazem / Q000494:pharmacology; D004594:Electrophysiology; D005260:Female; D009529:Nicardipine / Q000494:pharmacology; D010010:Osteoclasts / Q000187:drug effects / Q000502:physiology*; D011189:Potassium Chloride / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology
D015220:Calcium Channels; D011189:Potassium Chloride; D014700:Verapamil; D009529:Nicardipine; D004110:Diltiazem